Cardiology

Catherine B. Gretchen, MD, and Arpana S. Rayannavar, MD

I. Websites

http://www.pted.org

http://www.murmurlab.org

II. The Cardiac Cycle (Fig. 7-1)

III. Physical Examination

A. Heart Rate

Refer to Table 7-4 for normal heart rate (HR) by age.

B. Blood Pressure

1. Blood pressure:

a. Blood pressure norms (systolic blood pressure [SBP], diastolic blood pressure [DBP]) by age 1,2: Tables 7-1 and 7-2; Figs. 7-2, 7-3, and 7-4

For blood pressure norms for preterm infants, see Expert Consult: Table EC 7-A

2. Pulse pressure = systolic pressure − diastolic pressure.

a. Wide pulse pressure (>40 mmHg): Differential diagnosis includes aortic insufficiency, arteriovenous fistula, patent ductus arteriosus, thyrotoxicosis, warm shock.

b. Narrow pulse pressure (<25 mmHg): Differential diagnosis includes aortic stenosis, pericardial effusion, pericardial tamponade, pericarditis, significant tachycardia, cold shock.

3. Mean arterial pressure (MAP)

a. MAP = diastolic pressure + (pulse pressure/3) OR 1/3 systolic pressure + 2/3 diastolic pressure.

b. Preterm infants and newborns: Normal MAP = gestational age in weeks + 5.

4. Abnormalities in blood pressure

a. Four-limb blood pressure measurements can be used to assess for coarctation of the aorta; pressure must be measured in both the right and left arms because of the possibility of an aberrant right subclavian artery.

b. Pulsus paradoxus: Exaggeration of the normal drop in SBP seen with inspiration. Determine SBP at the end of exhalation and then during inhalation; if the difference is > 10 mmHg, consider pericardial effusion, tamponade, pericarditis, severe asthma, or restrictive cardiomyopathies.

C. Heart Sounds

1. S₁: Associated with closure of mitral and tricuspid valves; heard best at the apex or left lower sternal border (LLSB).

2. S₂: Associated with closure of pulmonary and aortic valves; heard best at the left upper sternal border (LUSB) and has normal physiologic splitting that increases with inspiration.

3. S₃: Heard best at the apex or LLSB.

4. S₄: Heard at the apex.

D. Systolic and Diastolic Sounds

See Box 7-1 for abnormal heart sounds.³

E. Murmurs⁴

More information at http://www.murmurlab.org. Clinical characteristics summarized in Table 7-3.³

TABLE EC7-A

BLOOD PRESSURES AFTER 2 WEEKS OF AGE IN INFANTS FROM 26–44 WEEKS POSTCONCEPTIONAL AGE

Postconceptional Age	50th Percentile	95th Percentile	99th Percentile
44 WEEKS
SBP	88	105	110
DBP	50	68	73
MAP	63	80	85
42 WEEKS
SBP	85	98	102
DBP	50	65	70
MAP	62	76	81
40 WEEKS
SBP	80	95	100
DBP	50	65	70
MAP	60	75	80
38 WEEKS
SBP	77	92	97
DBP	50	65	70
MAP	59	74	79
36 WEEKS
SBP	72	87	92
DBP	50	65	70
MAP	57	72	71
34 WEEKS
SBP	70	85	90
DBP	40	55	60
MAP	50	65	70
32 WEEKS
SBP	68	83	88
DBP	40	55	60
MAP	48	62	69
30 WEEKS
SBP	65	80	85
DBP	40	55	60
MAP	48	65	68
28 WEEKS
SBP	60	75	80
DBP	38	50	54
MAP	45	58	63
26 WEEKS
SBP	55	72	77
DBP	30	50	56
MAP	38	57	63

DBP, Diastolic blood pressure; MAP, mean arterial pressure; SBP, systolic blood pressure.

Data from Dionne J et al. Hypertension in infancy: diagnosis, management, and outcome. Pediatr Nephrol. 2012;27:17-32.

FIGURE 7-2 Age-specific percentiles of blood pressure (BP) measurements in boys from birth to 12 months of age; Korotkoff phase IV (K4) used for diastolic BP. (From Task Force on Blood Pressure Control in Children. Report of the Second Task Force on Blood Pressure Control in Children. Pediatrics. 1987;79:1-25.)

TABLE 7-1

BLOOD PRESSURE LEVELS FOR THE 50TH, 90TH, 95TH, AND 99TH PERCENTILES OF BLOOD PRESSURE FOR GIRLS AGE 1–17 YEARS BY PERCENTILES OF HEIGHT ²

Age, yr	BP Percentile^†	SBP, mmHg							DBP, mmHg
		Percentile of Height^∗							Percentile of Height^∗
		5th	10th	25th	50th	75th	90th	95th	5th	10th	25th	50th	75th	90th	95th
1	50th	83	84	85	86	88	89	90	38	39	39	40	41	41	42
	90th	97	97	98	100	101	102	103	52	53	53	54	55	55	56
	95th	100	101	102	104	105	106	107	56	57	57	58	59	59	60
	99th	108	108	109	111	112	113	114	64	64	65	65	66	67	67
2	50th	85	85	87	88	89	91	91	43	44	44	45	46	46	47
	90th	98	99	100	101	103	104	105	57	58	58	59	60	61	61
	95th	102	103	104	105	107	108	109	61	62	62	63	64	65	65
	99th	109	110	111	112	114	115	116	69	69	70	70	71	72	72
3	50th	86	87	88	89	91	92	93	47	48	48	49	50	50	51
	90th	100	100	102	103	104	106	106	61	62	62	63	64	64	65
	95th	104	104	105	107	108	109	110	65	66	66	67	68	68	69
	99th	111	111	113	114	115	116	117	73	73	74	74	75	76	76
4	50th	88	88	90	91	92	94	94	50	50	51	52	52	53	54
	90th	101	102	103	104	106	107	108	64	64	65	66	67	67	68
	95th	105	106	107	108	110	111	112	68	68	69	70	71	71	72
	99th	112	113	114	115	117	118	119	76	76	76	77	78	79	79
5	50th	89	90	91	93	94	95	96	52	53	53	54	55	55	56
	90th	103	103	105	106	107	109	109	66	67	67	68	69	69	70
	95th	107	107	108	110	111	112	113	70	71	71	72	73	73	74
	99th	114	114	116	117	118	120	120	78	78	79	79	80	81	81
Table Continued

Age, yr	BP Percentile^†	SBP, mmHg							DBP, mmHg
		Percentile of Height^∗							Percentile of Height^∗
		5th	10th	25th	50th	75th	90th	95th	5th	10th	25th	50th	75th	90th	95th
6	50th	91	92	93	94	96	97	98	54	54	55	56	56	57	58
	90th	104	105	106	108	109	110	111	68	68	69	70	70	71	72
	95th	108	109	110	111	113	114	115	72	72	73	74	74	75	76
	99th	115	116	117	119	120	121	122	80	80	80	81	82	83	83
7	50th	93	93	95	96	97	99	99	55	56	56	57	58	58	59
	90th	106	107	108	109	111	112	113	69	70	70	71	72	72	73
	95th	110	111	112	113	115	116	116	73	74	74	75	76	76	77
	99th	117	118	119	120	122	123	124	81	81	82	82	83	84	84
8	50th	95	95	96	98	99	100	101	57	57	57	58	59	60	60
	90th	108	109	110	111	113	114	114	71	71	71	72	73	74	74
	95th	112	112	114	115	116	118	118	75	75	75	76	77	78	78
	99th	119	120	121	122	123	125	125	82	82	83	83	84	85	86
9	50th	96	97	98	100	101	102	103	58	58	58	59	60	61	61
	90th	110	110	112	113	114	116	116	72	72	72	73	74	75	75
	95th	114	114	115	117	118	119	120	76	76	76	77	78	79	79
	99th	121	121	123	124	125	127	127	83	83	84	84	85	86	87
10	50th	98	99	100	102	103	104	105	59	59	59	60	61	62	62
	90th	112	112	114	115	116	118	118	73	73	73	74	75	76	76
	95th	116	116	117	119	120	121	122	77	77	77	78	79	80	80
Table Continued

Age, yr	BP Percentile^†	SBP, mmHg							DBP, mmHg
		Percentile of Height^∗							Percentile of Height^∗
		5th	10th	25th	50th	75th	90th	95th	5th	10th	25th	50th	75th	90th	95th
	99th	123	123	125	126	127	129	129	84	84	85	86	86	87	88
11	50th	100	101	102	103	105	106	107	60	60	60	61	62	63	63
	90th	114	114	116	117	118	119	120	74	74	74	75	76	77	77
	95th	118	118	119	121	122	123	124	78	78	78	79	80	81	81
	99th	125	125	126	128	129	130	131	85	85	86	87	87	88	89
12	50th	102	103	104	105	107	108	109	61	61	61	62	b3	64	64
	90th	116	116	117	119	120	121	122	75	75	75	76	77	78	78
	95th	119	120	121	123	124	125	126	79	79	79	80	81	82	82
	99th	127	127	128	130	131	132	133	86	86	87	88	88	89	90
13	50th	104	105	106	107	109	110	110	62	62	62	63	64	65	65
	90th	117	118	119	121	122	123	124	76	76	76	77	78	79	79
	95th	121	122	123	124	126	127	128	80	80	80	81	82	83	83
	99th	128	129	130	132	133	134	135	87	87	88	89	89	90	91
14	50th	106	106	107	109	110	111	112	63	63	63	64	65	66	66
	90th	119	120	121	122	124	125	125	77	77	77	78	79	80	80
	95th	123	123	125	126	127	129	129	81	81	81	82	83	84	84
	99th	130	131	132	133	135	136	136	88	88	89	90	90	91	92
15	50th	107	108	109	110	111	113	113	64	64	64	65	66	67	67
	90th	120	121	122	123	125	126	127	78	78	78	79	80	81	81
	95th	124	125	126	127	129	130	131	82	82	82	83	84	85	85
Table Continued

Age, yr	BP Percentile^†	SBP, mmHg							DBP, mmHg
		Percentile of Height^∗							Percentile of Height^∗
		5th	10th	25th	50th	75th	90th	95th	5th	10th	25th	50th	75th	90th	95th
	99th	131	132	133	134	136	137	138	89	89	90	91	91	92	93
16	50th	108	108	110	111	112	114	114	64	64	65	66	66	67	68
	90th	121	122	123	124	126	127	128	78	78	79	80	81	81	82
	95th	125	126	127	128	130	131	132	82	82	83	84	85	85	86
	99th	132	133	134	135	137	138	139	90	90	90	91	92	93	93
17	50th	108	109	110	111	113	114	115	64	65	65	66	67	67	68
	90th	122	122	123	125	126	127	128	78	79	79	80	81	81	82
	95th	125	126	127	129	130	131	132	82	83	83	84	85	85	86
	99th	133	133	134	136	137	138	139	90	90	91	91	92	93	93

^∗ Height percentile determined by standard growth curves.

† Blood pressure percentile determined by a single measurement.

Adapted from National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents. The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. Pediatrics. 2004;114(2 Suppl):555-576.

TABLE 7-2

BLOOD PRESSURE LEVELS FOR THE 50TH, 90TH, 95TH, AND 99TH PERCENTILES OF BLOOD PRESSURE FOR BOYS AGE 1–17 YEARS BY PERCENTILES OF HEIGHT ²

Age, yr	BP Percentile^†	SBP, mmHg							DBP, mmHg
		Percentile of Height^∗							Percentile of Height^∗
		5th	10th	25th	50th	75th	90th	95th	5th	10th	25th	50th	75th	90th	95th
1	50th	80	81	83	85	87	88	89	34	35	36	37	38	39	39
	90th	94	95	97	99	100	102	103	49	50	51	52	53	53	54
	95th	98	99	101	103	104	106	106	54	54	55	56	57	58	58
	99th	105	106	108	110	112	113	114	61	62	63	64	65	66	66
2	50th	84	85	87	88	90	92	92	39	40	41	42	43	44	44
	90th	97	99	100	102	104	105	106	54	55	56	57	58	58	59
	95th	101	102	104	106	108	109	110	59	59	60	61	62	63	63
	99th	109	110	111	113	115	117	117	66	67	68	69	70	71	71
3	50th	86	87	89	91	93	94	95	44	44	45	46	47	48	48
	90th	100	101	103	105	107	108	109	59	59	60	61	62	63	63
	95th	104	105	107	109	110	112	113	63	63	64	65	66	67	67
	99th	111	112	114	116	118	119	120	71	71	72	73	74	75	75
4	50th	88	89	91	93	95	96	97	47	48	49	50	51	51	52
	90th	102	103	105	107	109	110	111	62	63	64	65	66	66	67
	95th	106	107	109	111	112	114	115	66	67	68	69	70	71	71
	99th	113	114	116	118	120	121	122	74	75	76	77	78	78	79
5	50th	90	91	93	95	96	98	98	50	51	52	53	54	55	55
	90th	104	105	106	108	110	111	112	65	66	67	68	69	69	70
	95th	108	109	110	112	114	115	116	69	70	71	72	73	74	74
	99th	115	116	118	120	121	123	123	77	78	79	80	81	81	82
6	50th	91	92	94	96	98	99	100	53	53	54	55	56	57	57
	90th	105	166	108	110	111	113	113	68	68	69	70	71	72	72
	95th	109	110	112	114	115	117	117	72	72	73	74	75	76	76
	99th	116	117	119	121	123	124	125	80	80	81	82	83	84	84
Table Continued

Age, yr	BP Percentile^†	SBP, mmHg							DBP, mmHg
		Percentile of Height^∗							Percentile of Height^∗
		5th	10th	25th	50th	75th	90th	95th	5th	10th	25th	50th	75th	90th	95th
7	50th	92	94	95	97	99	100	101	55	55	56	57	58	59	59
	90th	106	107	109	111	113	114	115	70	70	71	72	73	74	74
	95th	110	111	113	115	117	118	119	74	74	75	76	77	78	78
	99th	117	118	120	122	124	125	126	82	82	83	84	85	86	86
8	50th	94	95	97	99	100	102	102	56	57	58	59	60	60	61
	90th	107	109	110	112	114	115	116	71	72	72	73	74	75	76
	95th	111	112	114	116	118	119	120	75	76	77	78	79	79	80
	99th	119	120	122	123	125	127	127	83	84	85	86	87	87	88
9	50th	95	96	98	100	102	103	104	57	58	59	60	61	61	62
	90th	109	110	112	114	115	117	118	72	73	74	75	76	76	77
	95th	113	114	116	118	119	121	121	76	77	78	79	80	81	81
	99th	120	121	123	125	127	128	129	84	85	86	87	88	88	89
10	50th	97	98	100	102	103	105	106	58	59	60	61	61	62	63
	90th	111	112	114	115	117	119	119	73	73	74	75	76	77	78
	95th	115	116	117	119	121	122	123	77	78	79	80	81	81	82
	99th	122	123	125	127	128	130	130	85	86	86	88	88	89	90
11	50th	99	100	102	104	105	107	107	59	59	60	61	62	63	63
	90th	113	114	115	117	119	120	121	74	74	75	76	77	78	78
	95th	117	118	119	121	123	124	125	78	78	79	80	81	82	82
	99th	124	125	127	129	130	132	132	86	86	87	88	89	90	90
12	50th	101	102	104	106	108	109	110	59	60	61	62	63	63	64
	90th	115	116	118	120	121	123	123	74	75	75	76	77	78	79
	95th	119	120	122	123	125	127	127	78	79	80	81	82	82	83
	99th	126	127	129	131	133	134	135	86	87	88	89	90	90	91
Table Continued

Age, yr	BP Percentile^†	SBP, mmHg							DBP, mmHg
		Percentile of Height^∗							Percentile of Height^∗
		5th	10th	25th	50th	75th	90th	95th	5th	10th	25th	50th	75th	90th	95th
13	50th	104	105	106	108	110	111	112	60	60	61	62	63	64	64
	90th	117	118	120	122	124	125	126	75	75	76	77	78	79	79
	95th	121	122	124	126	128	129	130	79	79	80	81	82	83	83
	99th	128	130	131	133	135	136	137	87	87	88	89	90	91	91
14	50th	106	107	109	111	113	114	115	60	61	62	63	64	65	65
	90th	120	121	123	125	126	128	128	75	76	77	78	79	79	80
	95th	124	125	127	128	130	132	132	80	80	81	82	83	84	84
	99th	131	132	134	136	138	139	140	87	88	89	90	91	92	92
15	50th	109	110	112	113	115	117	117	61	62	63	64	65	66	66
	90th	122	124	125	127	129	130	131	76	77	78	79	80	80	81
	95th	126	127	129	131	133	134	135	81	81	82	83	84	85	85
	99th	134	135	136	138	140	142	142	88	89	90	91	92	93	93
16	50th	111	112	114	116	118	119	120	63	63	64	65	66	67	67
	90th	125	126	128	130	131	133	134	78	78	79	80	81	82	82
	95th	129	130	132	134	135	137	137	82	83	83	84	85	86	87
	99th	136	137	139	141	143	144	145	90	90	91	92	93	94	94
17	50th	114	115	116	118	120	121	122	65	66	66	67	68	69	70
	90th	127	128	130	132	134	135	136	80	80	81	82	83	84	84
	95th	131	232	134	136	138	139	140	84	85	86	87	87	88	89
	99th	139	140	141	143	145	146	147	92	93	93	94	95	96	97

^∗ Height percentile determined by standard growth curves.

† Blood pressure percentile determined by a single measurement.

Adapted from National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents: The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. Pediatrics 2004;114(2 Suppl):555–576.

1. Grading of heart murmurs: Intensified by states of higher cardiac output (e.g., anemia, anxiety, fever, exercise)³

a. Grade I: Barely audible

b. Grade II: Soft but easily audible

c. Grade III: Moderately loud but not accompanied by a thrill

d. Grade IV: Louder, associated with a thrill

e. Grade V: Audible with a stethoscope barely on the chest

f. Grade VI: Audible with a stethoscope off the chest

FIGURE 7-3 Age-specific percentile of blood pressure (BP) measurements in girls from birth to 12 months of age; Korotkoff phase IV (K4) used for diastolic BP. (From Task Force on Blood Pressure Control in Children. Report of the Second Task Force on Blood Pressure Control in Children. Pediatrics. 1987;79:1-25.)

2. Benign heart murmurs:

a. Caused by a disturbance of the laminar flow of blood; frequently produced as the diameter of the blood's pathway decreases and velocity increases.

b. Present in > 80% of children sometime during childhood, most commonly beginning at age 3 to 4 years.

c. Accentuated in high-output states, especially with fever and anemia.

d. Normal electrocardiogram (ECG) and radiographic findings.

NOTE: ECG and chest radiograph are not routinely useful or cost-effective screening tools for distinguishing benign from pathologic murmurs.

FIGURE 7-4 Linear regression of mean systolic blood pressure on postconceptional age (gestational age in weeks plus weeks after delivery). CL, Confidence limit. (Data from Zubrow AB, Hulman S, Kushner H, et al. Determinants of blood pressure in infants admitted to neonatal intensive care units: a prospective multicenter study. Philadelphia Neonatal Blood Pressure Study Group. J Perinatol. 1995;15:470-479.)

BOX 7-1 SUMMARY OF ABNORMAL HEART SOUNDS

• Widely split S₁: Ebstein anomaly, RBBB

• Widely split and fixed S₂: Right ventricular volume overload (e.g., ASD, PAPVR), pressure overload (e.g., PS), electrical delay in RV contraction (e.g., RBBB), early aortic closure (e.g., MR), occasionally heard in normal child

• Narrowly split S₂: Pulmonary hypertension, AS, delay in LV contraction (e.g., LBBB), occasionally heard in normal child

• Single S₂: Pulmonary hypertension, one semilunar valve (e.g., pulmonary atresia, aortic atresia, truncus arteriosus), P2 not audible (e.g., TGA, TOF, severe PS), severe AS, occasionally heard in normal child

• Paradoxically split S₂: Severe AS, LBBB, Wolff-Parkinson-White syndrome (type B)

• Abnormal intensity of P2: Increased P2 (e.g., pulmonary hypertension), decreased P2 (e.g., severe PS, TOF, TS)

• S₃: Occasionally heard in healthy children or adults or may indicate dilated ventricles (e.g., large VSD, CHF)

• S₄: Always pathologic; decreased ventricular compliance

• Ejection click: Heard with stenosis of the semilunar valves, dilated great arteries in the setting of pulmonary or systemic hypertension, idiopathic dilation of the PA, TOF, persistent truncus arteriosus

• Midsystolic click: Heard at the apex in mitral valve prolapse

• Diastolic opening snap: Rare in children; associated with TS/MS

AS, Aortic stenosis; ASD, atrial septal defect; CHF, congestive heart failure; LBBB, left bundle-branch block; MR, mitral regurgitation; MS, mitral stenosis; PA, pulmonary artery; PAPVR, partial anomalous pulmonary venous return; PS, pulmonary stenosis; RBBB, right bundle-branch block; RV, right ventricular; TGA, transposition of the great arteries; TOF, tetralogy of Fallot; TS, tricuspid stenosis; VSD, ventricular septal defect.

Modified from Park MK. Pediatric Cardiology for Practitioners. 5th ed. St Louis: Mosby; 2008:25.

3. Likely pathologic murmur when one or more of the following are present: Symptoms; cyanosis; systolic murmur that is loud (grade ≥3/6), harsh, pansystolic, or long in duration; diastolic murmur; abnormal heart sounds; presence of a click; abnormally strong or weak pulses.

4. Systolic and diastolic heart murmurs (Box 7-2)

TABLE 7-3

COMMON INNOCENT HEART MURMURS

Type (Timing)	Description of Murmur	Age Group
Classic vibratory murmur (Still's murmur; systolic)	Maximal at LMSB or between LLSB and apex Grade 2–3/6 in intensity Low-frequency vibratory, twanging string, groaning, squeaking, or musical	3–6 yr; occasionally in infancy
Pulmonary ejection murmur (systolic)	Maximal at LUSB Early to midsystolic Grade 1–3/6 in intensity Blowing in quality	8–14 yr
Pulmonary flow murmur of newborn (systolic)	Maximal at LUSB Transmits well to left and right chest, axilla, and back Grade 1–2/6 in intensity	Premature and full-term newborns Usually disappears by 3–6 mo
Venous hum (continuous)	Maximal at right (or left) supraclavicular and infraclavicular areas Grade 1–3/6 in intensity Inaudible in supine position Intensity changes with rotation of head and disappears with compression of jugular vein.	3–6 yr
Carotid bruit (systolic)	Right supraclavicular area over carotids Grade 2–3/6 in intensity Occasional thrill over carotid	Any age

LLSB, Left lower sternal border; LMSB, left middle sternal border; LUSB, left upper sternal border.

From Park MK. Pediatric Cardiology for Practitioners. 5th ed. St Louis: Mosby; 2008:36.

BOX 7-2 SYSTOLIC AND DIASTOLIC HEART MURMURS

I. RUSB

Aortic valve stenosis (supravalvar, subvalvar)

Aortic regurgitation

II. LUSB

Pulmonary valve stenosis

Atrial septal defect

Pulmonary ejection murmur, innocent

Pulmonary flow murmur of newborn

Pulmonary artery stenosis

Aortic stenosis

Coarctation of the aorta

Patent ductus arteriosus

Partial anomalous pulmonary venous return (PAPVR)

Total anomalous pulmonary venous return (TAPVR)

Pulmonary regurgitation

III. LLSB

Ventricular septal defect, including atrioventricular septal defect

Vibratory innocent murmur (Still's murmur)

HOCM (IHSS)

Tricuspid regurgitation

Vibratory innocent murmur (Still's murmur)

Mitral valve prolapse

Aortic stenosis

HOCM (IHSS)

Mitral stenosis

The location at which various murmurs may be heard. Diastolic murmurs are in italics. HOCM, Hypertrophic obstructive cardiomyopathy; IHSS, idiopathic hypertrophic subaortic stenosis; LLSB, left lower sternal border; LUSB, left upper sternal border; RUSB, right upper sternal border.

From Park MK. Pediatric Cardiology for Practitioners. 5th ed. St Louis: Mosby; 2008:30.

IV. Electrocardiography

A. Basic Electrocardiography Principles

1. Lead placement (Fig. 7-5)

2. ECG complexes (see Fig. 7-1)

a. P wave: Represents atrial depolarization

b. QRS complex: Represents ventricular depolarization

c. T wave: Represents ventricular repolarization

d. U wave: May follow T wave, representing late phases of ventricular repolarization

3. Systematic approach for evaluating ECGs (Table 7-4 shows normal ECG parameters)^3,5:

a. Rate

(1) Standardization: Paper speed is 25 mm/sec. One small square = 1 mm = 0.04 sec. One large square = 5 mm = 0.2 sec. Amplitude standard: 10 mm = 1 mV

(2) Calculation: HR (beats per minute) = 60 divided by the average R-R interval in seconds, or 1500 divided by the R-R interval in millimeters

b. Rhythm

(1) Sinus rhythm: Every QRS complex is preceded by a P wave, normal PR interval (although PR interval may be prolonged, as in first-degree atrioventricular [AV] block), and normal P-wave axis (upright P in lead I and aVF).

FIGURE 7-5 A, Hexaxial reference system. B, Horizontal reference system. (Modified from Park MK, Guntheroth WG. How to Read Pediatric ECGs. 4th ed. Philadelphia: Mosby; 2006:3.)

(2) There is normal respiratory variation of the R-R interval without morphologic changes of the P wave or QRS complex.

c. Axis: Look at the direction of the QRS in leads I and aVF. Determine quadrant and compare with age-matched normal values (Fig. 7-6; see Table 7-4).

d. Intervals (PR, QRS, QTc): See Table 7-4 for normal PR and QRS intervals. The QTc is calculated using the Bazett formula:

QTc=QT (sec) measured/√R-R

(average 3 measurements taken from same lead)

R-R interval should extend from the R wave in the QRS complex where you are measuring QT to the preceding R wave. Normal values for QTc are:

(1) 0.44 sec is 97th percentile for infants 3–4 days old⁶

(2) ≤0.45 sec in all males >1 week of age and prepubescent females

(3) ≤0.46 sec for postpubescent females

e. P-wave size and shape: Normal P wave should be <0.10 sec in children, <0.08 sec in infants, with amplitude <0.3 mV (3 mm in height, with normal standardization)

f. R-wave progression: Generally a normal increase in R-wave size and decrease in S-wave size from leads V₁ to V₆ (with dominant S waves in right precordial leads and dominant R waves in left precordial leads), representing dominance of left ventricular forces. However, newborns and infants have a normal dominance of the right ventricle.

g. Q waves: Normal Q waves usually <0.04 sec in duration and <25% of total QRS amplitude. Q waves are <5 mm deep in left precordial leads and aVF and ≤8 mm deep in lead III for children <3 years of age.

FIGURE 7-6 Locating quadrants of mean QRS axis from leads I and aVF. (From Park MK, Guntheroth WG. How to Read Pediatric ECGs. 4th ed. Philadelphia: Mosby; 2006:17.)

TABLE 7-4

NORMAL PEDIATRIC ELECTROCARDIOGRAM (ECG) PARAMETERS

Age	Heart Rate (bpm)	QRS Axis^∗	PR Interval (sec)^∗	QRS Duration (sec)^†	Lead V₁			Lead V₆
Age	Heart Rate (bpm)	QRS Axis^∗	PR Interval (sec)^∗	QRS Duration (sec)^†	R-Wave Amplitude (mm)^†	S-Wave Amplitude (mm)^†	R/S Ratio	R-Wave Amplitude (mm)^†	S-Wave Amplitude (mm)^†	R/S Ratio
0–7 days	95–160 (125)	+30 to 180 (110)	0.08–0.12 (0.10)	0.05 (0.07)	13.3 (25.5)	7.7 (18.8)	2.5	4.8 (11.8)	3.2 (9.6)	2.2
1–3 wk	105–180 (145)	+30 to 180 (110)	0.08–0.12 (0.10)	0.05 (0.07)	10.6 (20.8)	4.2 (10.8)	2.9	7.6 (16.4)	3.4 (9.8)	3.3
1–6 mo	110–180 (145)	+10 to +125 (+70)	0.08–0.13 (0.11)	0.05 (0.07)	9.7 (19)	5.4 (15)	2.3	12.4 (22)	2.8 (8.3)	5.6
6–12 mo	110–170 (135)	+10 to +125 (+60)	0.10–0.14 (0.12)	0.05 (0.07)	9.4 (20.3)	6.4 (18.1)	1.6	12.6 (22.7)	2.1 (7.2)	7.6
1–3 yr	90–150 (120)	+10 to +125 (+60)	0.10–0.14 (0.12)	0.06 (0.07)	8.5 (18)	9 (21)	1.2	14 (23.3)	1.7 (6)	10
4–5 yr	65–135 (110)	0 to +110 (+60)	0.11–0.15 (0.13)	0.07 (0.08)	7.6 (16)	11 (22.5)	0.8	15.6 (25)	1.4 (4.7)	11.2
6–8 yr	60–130 (100)	−15 to +110 (+60)	0.12–0.16 (0.14)	0.07 (0.08)	6 (13)	12 (24.5)	0.6	16.3 (26)	1.1 (3.9)	13
9–11 yr	60–110 (85)	−15 to +110 (+60)	0.12–0.17 (0.14)	0.07 (0.09)	5.4 (12.1)	11.9 (25.4)	0.5	16.3 (25.4)	1.0 (3.9)	14.3
12–16 yr	60–110 (85)	−15 to +110 (+60)	0.12–0.17 (0.15)	0.07 (0.10)	4.1 (9.9)	10.8 (21.2)	0.5	14.3 (23)	0.8 (3.7)	14.7
>16 yr	60–100 (80)	−15 to +110 (+60)	0.12–0.20 (0.15)	0.08 (0.10)	3 (9)	10 (20)	0.3	10 (20)	0.8 (3.7)	12

∗ Normal range and (mean).

† Mean and (98th percentile).

Adapted from Park MK. Pediatric Cardiology for Practitioners. 5th ed. St Louis: Mosby; 2008; and Davignon A et al. Normal ECG standards for infants and children. Pediatr Cardiol. 1979;1:123-131.

TABLE 7-5

NORMAL T-WAVE AXIS

Age	V₁, V₂	AVF	I, V₅, V₆
Birth–1 day	±	+	±
1–4 days	±	+	+
4 days to adolescent	−	+	+
Adolescent to adult	+	+	+

+, T wave positive; −, T wave negative; ±, T wave normally either positive or negative.

h. ST-segment (Fig. 7-7): ST-segment elevation or depression >1 mm in limb leads and >2 mm in precordial leads is consistent with myocardial ischemia or injury. Note: J-depression is an upsloping of the ST segment and a normal variant.

i. T wave:

(1) Inverted T waves in V₁ and V₂ can be normal in children up to adolescence (Table 7-5).

(2) Tall, peaked T waves may be seen in hyperkalemia.

(3) Flat or low T waves may be seen in hypokalemia, hypothyroidism, normal newborns, and myocardial/pericardial ischemia and inflammation.

FIGURE 7-7 Nonpathologic (nonischemic) and pathologic (ischemic) ST and T changes. A, Characteristic nonischemic ST-segment alteration called J-depression; note that ST slope is upward. B–C, Ischemic or pathologic ST-segment alterations. B, Downward slope of ST segment. C, Horizontal segment is sustained. (From Park MK, Guntheroth WG. How to Read Pediatric ECGs. 4th ed. Philadelphia: Mosby; 2006:107.)

FIGURE 7-8 Criteria for atrial enlargement. CAE, Combined atrial enlargement; LAE, left atrial enlargement; RAE, right atrial enlargement. (From Park MK. Pediatric Cardiology for Practitioners. 5th ed. St Louis: Mosby; 2008:53.)

j. Hypertrophy/enlargement

(1) Atrial enlargement (Fig. 7-8)

(2) Ventricular hypertrophy: Diagnosed by QRS axis, voltage, and R/S ratio (Box 7-3; see also Table 7-4)

B. ECG Abnormalities

1. Nonventricular arrhythmias (Table 7-6; Figs. 7-9 and 7-10)⁷

2. Ventricular arrhythmias (Table 7-7; Fig. 7-11)

3. Nonventricular conduction disturbances (Fig. 7-12 and Table 7-8)⁸

4. Ventricular conduction disturbances (Table 7-9)

FIGURE 7-9 Supraventricular arrhythmias. p¹, Premature atrial contraction. (From Park MK, Guntheroth WG. How to Read Pediatric ECGs. 4th ed. Philadelphia: Mosby; 2006:129.)

FIGURE 7-10 Supraventricular tachycardia pathway: Mechanism for orthodromic reentry tract (ORT), (i.e., Wolff-Parkinson-White [WPW]). Diagram shows sinoatrial (SA) node (upper left circle), with atrioventricular (AV) node (above horizontal line) and bundle branches crossing to ventricle (below horizontal line). (Adapted from Walsh EP. Cardiac arrhythmias. In: Fyler DC,ed. Nadas’ Pediatric Cardiology. Philadelphia: Hanley & Belfus; 1992:384.)

FIGURE 7-11 Ventricular arrhythmias. p, p wave, RR, R-R interval. (From Park MK, Guntheroth WG. How to Read Pediatric ECGs. 4th ed. Philadelphia: Mosby; 2006:138.)

FIGURE 7-12 Conduction blocks. p, p wave; R, QRS complex. (From Park MK, Guntheroth WG. How to Read Pediatric ECGs. 4th ed. Philadelphia: Mosby; 2006:141.)

TABLE 7-6

NONVENTRICULAR ARRHYTHMIAS

Name/Description	Cause	Treatment
SINUS
TACHYCARDIA
Normal sinus rhythm with HR >95th percentile for age (usually infants: <220 beats/min and children: <180 beats/min)	Hypovolemia, shock, anemia, sepsis, fever, anxiety, CHF, PE, myocardial disease, drugs (e.g., β-agonists, albuterol, caffeine, atropine)	Address underlying cause
BRADYCARDIA
Normal sinus rhythm with HR <5th percentile for age	Normal (especially in athletic individuals), increased ICP, hypoxia, hyperkalemia, hypercalcemia, vagal stimulation, hypothyroidism, hypothermia, drugs (e.g., opioids, digoxin, β-blockers), long QT	Address underlying cause; if symptomatic, refer to inside back cover for bradycardia algorithm
SUPRAVENTRICULAR^∗
PREMATURE ATRIAL CONTRACTION (PAC)
Narrow QRS complex; ectopic focus in atria with abnormal P-wave morphology	Digitalis toxicity, medications (e.g., caffeine, theophylline, sympathomimetics), normal variant	Treat digitalis toxicity; otherwise no treatment needed
ATRIAL FLUTTER
Atrial rate 250–350 beats/min; characteristic sawtooth or flutter pattern with variable ventricular response rate and normal QRS complex	Dilated atria, previous intra-atrial surgery, valvular or ischemic heart disease, idiopathic in newborns	Synchronized cardioversion or overdrive pacing; treat underlying cause
Table Continued

Name/Description	Cause	Treatment
ATRIAL FIBRILLATION
Irregular; atrial rate 350–600 beats/min, yielding characteristic fibrillatory pattern (no discrete P waves) and irregular ventricular response rate of about 110–150 beats/min with normal QRS complex	Wolff-Parkinson-White syndrome and those listed previously for atrial flutter (except not idiopathic), alcohol exposure, familial	Synchronized cardioversion; then may need anticoagulation pretreatment
SVT
Sudden run of three or more consecutive premature supraventricular beats at >220 beats/min(infant) or >180 beats/min (child), with narrow QRS complex and absent/abnormal P wave; either sustained (>30 sec) or nonsustained	Most commonly idiopathic but may be seen in congenital heart disease (e.g., Ebstein anomaly, transposition)	Vagal maneuvers, adenosine; if unstable, need immediate synchronized cardioversion (0.5 J/kg up to 1 J/kg). Consult cardiologist. See “Tachycardia with Poor Perfusion” or “Tachycardia with Adequate Perfusion” algorithms in back of handbook.
I. AV Reentrant: Presence of accessory bypass pathway, in conjunction with AV node, establishes cyclic pattern of reentry independent of SA node; most common cause of nonsinus tachycardia in children (see Wolff-Parkinson-White syndrome, Table 7-9 and Fig. 7-10)
II. Junctional: Automatic focus; simultaneous depolarization of atria and ventricles yields invisible P wave or retrograde P wave	Cardiac surgery, idiopathic	Adjust for clinical situation; consult cardiology
III. Ectopic atrial tachycardia: Rapid firing of ectopic focus in atrium	Idiopathic	AV nodal blockade, ablation
NODAL ESCAPE/JUNCTIONAL RHYTHM
Abnormal rhythm driven by AV node impulse, giving normal QRS complex and invisible P wave (buried in preceding QRS or T wave) or retrograde P wave (negative in lead II, positive in aVR); seen in sinus bradycardia	Common after surgery of atria	Often requires no treatment. If rate is slow enough, may require pacemaker.

AV, Atrioventricular; CHF, congestive heart failure; HR, heart rate; ICP, intracranial pressure; PE, pulmonary embolism; SA, sinoatrial; SVT, supraventricular tachycardia.

∗ Abnormal rhythm resulting from ectopic focus in atria or AV node, or from accessory conduction pathways. Characterized by different P-wave shape and abnormal P-wave axis. QRS morphology usually normal. See Figures 7-9, 7-10.⁶

TABLE 7-7

VENTRICULAR ARRHYTHMIAS

Name/Description	Cause	Treatment
PREMATURE VENTRICULAR CONTRACTION (PVC)
Ectopic ventricular focus causing early depolarization. Abnormally wide QRS complex appears prematurely, usually with full compensatory pause. May be unifocal or multifocal. Bigeminy: Alternating normal and abnormal QRS complexes. Trigeminy: Two normal QRS complexes followed by an abnormal one. Couplet: Two consecutive PVCs.	Myocarditis, myocardial injury, cardiomyopathy, long QT, congenital and acquired heart disease, drugs (catecholamines, theophylline, caffeine, anesthetics), MVP, anxiety, hypokalemia, hypoxia, hypomagnesemia. Can be normal variant.	None. More worrisome if associated with underlying heart disease or syncope, if worse with activity, or if they are multiform (especially couplets). Address underlying cause, rule out structural heart disease.
VENTRICULAR TACHYCARDIA
Series of three or more PVCs at rapid rate (120–250 beats/min), with wide QRS complex and dissociated, retrograde, or no P wave	See causes of PVCs (70% have underlying cause).	See “Tachycardia with Poor Perfusion” and “Tachycardia with Adequate Perfusion” algorithms in back of handbook.
VENTRICULAR FIBRILLATION
Depolarization of ventricles in uncoordinated asynchronous pattern, yielding abnormal QRS complexes of varying size and morphology with irregular, rapid rate. Rare in children.	Myocarditis, MI, postoperative state, digitalis or quinidine toxicity, catecholamines, severe hypoxia, electrolyte disturbances, long QT	Requires immediate defibrillation. See algorithm for “Asystole and Pulseless Arrest” at back of book.

MI, Myocardial infarction; MVP, mitral valve prolapse.

TABLE 7-8

NONVENTRICULAR CONDUCTION DISTURBANCES

Name/Description^∗	Cause	Treatment
FIRST-DEGREE HEART BLOCK
Abnormal but asymptomatic delay in conduction through AV node, yielding prolongation of PR interval	Acute rheumatic fever, tickborne (i.e., Lyme) disease, connective tissue disease, congenital heart disease, cardiomyopathy, digitalis toxicity, postoperative state, normal children	No specific treatment except address the underlying cause
SECOND-DEGREE HEART BLOCK: MOBITZ TYPE I (WENCKEBACH)
Progressive lengthening of PR interval until a QRS complex is not conducted. Common finding in asymptomatic teenagers.	Myocarditis, cardiomyopathy, congenital heart disease, postoperative state, MI, toxicity (digitalis, β-blocker), normal children, Lyme disease, lupus	Address underlying cause, or none needed
SECOND-DEGREE HEART BLOCK: MOBITZ TYPE II
Loss of conduction to ventricle without lengthening of the PR interval. May progress to complete heart block.	Same as for Mobitz type I	Address underlying cause; may need pacemaker
THIRD-DEGREE (COMPLETE) HEART BLOCK
Complete dissociation of atrial and ventricular conduction, with atrial rate faster than ventricular rate. P wave and PP interval regular; RR interval regular and much slower.	Congenital due to maternal lupus or other connective tissue disease	If bradycardic and symptomatic, consider pacing; see bradycardia algorithm at back of book.

AV, Atrioventricular; MI, myocardial infarction.

∗ High-degree AV block: Conduction of atrial impulse at regular intervals, yielding 2:1 block (two atrial impulses for each ventricular response), 3:1 block, etc.

TABLE 7-9

VENTRICULAR CONDUCTION DISTURBANCES

Name/Description	Criteria	Causes/Treatment
RIGHT BUNDLE-BRANCH BLOCK (RBBB)
Delayed right bundle conduction prolongs RV depolarization time, leading to wide QRS.	1. Prolonged or wide QRS with terminal slurred R′ (m-shaped RSR′ or RR′) in V₁, V₂, aVR 2. Wide and slurred S wave in leads I and V₆	ASD, surgery with right ventriculotomy, occasionally seen in normal children
LEFT BUNDLE-BRANCH BLOCK (LBBB)
Delayed left bundle conduction prolongs septal and LV depolarization time, leading to wide QRS with loss of usual septal signal; there is still a predominance of left ventricle forces. Rare in children.	1. Wide negative QS complex in lead V₁ with loss of septal R wave 2. Wide R or RR′ complex in lead V₆ with loss of septal Q wave	Hypertension, ischemic or valvular heart disease, cardiomyopathy
WOLFF-PARKINSON-WHITE (WPW)
Atrial impulse transmitted via anomalous conduction pathway to ventricles, bypassing AV node and normal ventricular conduction system. Leads to early and prolonged depolarization of ventricles. Bypass pathway is a predisposing condition for SVT.	1. Shortened PR interval 2. Delta wave 3. Wide QRS	Acute management of SVT if necessary as previously described; consider ablation of accessory pathway if recurrent SVT. All patients need cardiology referral.

ASD, Atrial septal defect; LV, left ventricle; RV, right ventricle; SVT, supraventricular tachycardia.

BOX 7-3 VENTRICULAR HYPERTROPHY CRITERIA

Right Ventricular Hypertrophy (RVH) Criteria

Must Have at Least One of the Following:

Upright T wave in lead V₁ after 3 days of age to adolescence

Presence of Q wave in V₁ (QR or QRS pattern)

Increased right and anterior QRS voltage (with normal QRS duration):

R in lead V₁, >98th percentile for age

S in lead V₆, >98th percentile for age

Right ventricular strain (associated with inverted T wave in V₁ with tall R wave)

Left Ventricular Hypertrophy (LVH) Criteria

Left ventricular strain (associated with inverted T wave in leads V₆, I, and/or aVF)

Supplemental Criteria:

Left axis deviation (LAD) for patient's age

Volume overload (associated with Q wave >5 mm and tall T waves in V₅ or V₆)

Increased QRS voltage in left leads (with normal QRS duration):

R in lead V₆ (and I, aVL, V₅), >98th percentile for age

S in lead V₁, >98th percentile for age

C. ECG Findings Secondary to Electrolyte Disturbances, Medications, and Systemic Illnesses (Table 7-10)^7,20

D. Long QT

1. Diagnosis:

a. In general, QTc is similar in males and females from birth until late adolescence (0.37–0.44 sec).

b. In adults, prolonged QTc is > 0.45 sec for males and > 0.45–0.46 sec for females.

c. In approximately 10% of cases, patients may have a normal QTc on ECG. Patients may also have a family history of long QT with unexplained syncope, seizure, or cardiac arrest without prolongation of QTc on ECG.

d. Treadmill exercise test may prolong the QTc and will sometimes incite arrythmias.

2. Complications: Associated with ventricular arrhythmias (torsades de pointes), syncope, and sudden death

3. Management:

a. Congenital long QT: β-blockers and/or defibrillators; rarely require cardiac sympathetic denervation or cardiac pacemakers

TABLE 7-10

SYSTEMIC EFFECTS ON ELECTROCARDIOGRAM

	Short QT	Long QT-U	Prolonged QRS	ST-T Changes	Sinus Tachycardia	Sinus Bradycardia	AV Block	Ventricular Tachycardia	Miscellaneous
CHEMISTRY
Hyperkalemia			X	X			X	X	Low-voltage Ps; peaked Ts
Hypokalemia		X		X
Hypercalcemia	X					X	X	X
Hypocalcemia		X			X		X
Hypermagnesemia							X
Hypomagnesemia		X
DRUGS
Digitalis	X			X		T	X	T
Phenothiazines		T						T
Phenytoin	X
Propranolol	X					X	X
Tricyclics		T	T	T	T		T	T
Verapamil						X	X
Table Continued

	Short QT	Long QT-U	Prolonged QRS	ST-T Changes	Sinus Tachycardia	Sinus Bradycardia	AV Block	Ventricular Tachycardia	Miscellaneous
MISCELLANEOUS
CNS injury		X		X	X	X	X
Friedreich ataxia				X	X				Atrial flutter
Duchenne muscular dystrophy					X	X			Atrial flutter
Myotonic dystrophy			X	X	X		X
Collagen vascular disease				X			X	X
Hypothyroidism						X			Low voltage
Hyperthyroidism			X	X	X		X
Lyme disease			X				X
Holt-Oram, maternal lupus							X

CNS, Central nervous system; T, present only with drug toxicity; X, present.

Adapted from Garson A Jr. The Electrocardiogram in Infants and Children: A Systematic Approach. Philadelphia: Lea & Febiger; 1983:172; and Walsh EP. Cardiac arrhythmias. In: Fyler DC, Nadas A,eds. Pediatric Cardiology. Philadelphia: Hanley & Belfus; 1992:141-143.

b. Acquired long QT: Treatment of arrhythmias, discontinue precipitating drug, correction of metabolic abnormalities

E. Hyperkalemia: ECG changes dependent on serum K⁺level; may have normal ECG with level between 2.5 and 6

1. Serum K⁺ <2.5: Depressed ST segment, diphasic T wave

2. Serum K⁺ >6: Tall T wave

3. Serum K⁺ >7.5: Long PR interval, wide QRS, tall T wave

4. Serum K⁺ >9: Absent P wave, sinusoidal

F. Myocardial Infarction (MI) in Children

1. Etiology: Anomalous origin or aberrant course of a coronary artery, Kawasaki disease, congenital heart disease (presurgical and postsurgical), and dilated cardiomyopathy. Less often associated with hypertension, lupus, myocarditis, cocaine ingestion, and use of adrenergic drugs (e.g., β-agonists used for asthma). Rare in children.

2. Frequent ECG findings in children with acute MI ⁹,¹⁰ (Fig. 7-13):

a. New-onset wide Q waves (>0.035 sec) seen within first few hours (persist over several years)

b. ST-segment elevation (>2 mm) seen within first few hours

c. Diphasic T waves seen within first few days (becoming sharply inverted, then normalizing over time)

d. Prolonged QTc interval (>0.44 sec) with abnormal Q waves

FIGURE 7-13 Sequential changes during myocardial infarction. (From Park MK, Guntheroth WG. How to Read Pediatric ECGs. 4th ed. Philadelphia: Mosby; 2006:115.)

e. Deep, wide Q waves in leads I, aVL, or V₆, without Q waves in II, III, aVF, suggest anomalous origin of the left coronary artery.

3. Other criteria:

a. Elevated creatine kinase (CK)/MB fraction: Not specific for acute MI in children

b. Cardiac troponin I: More sensitive indicator of early myocardial damage in children.¹⁰ Becomes elevated within hours of cardiac injury, persists for 4–7 days, is specific for cardiac injury.

V. Imaging

A. Chest Radiograph

Please see Chapter 25 for more information on the chest radiograph.

1. Evaluate the heart:

a. Size: Cardiac shadow should be <50% of thoracic width (maximal width between inner margins of ribs, as measured on a posteroanterior radiograph during inspiration)

b. Shape: Can aid in diagnosis of chamber/vessel enlargement and some congenital heart disease (Fig. 7-14)

c. Situs (levocardia, mesocardia, dextrocardia)

2. Evaluate the lung fields:

a. Decreased pulmonary blood flow: Seen in pulmonary or tricuspid stenosis/atresia, TOF, pulmonary hypertension (peripheral pruning)

b. Increased pulmonary blood flow: Seen as increased pulmonary vascular markings (PVMs) with redistribution from bases to apices of lungs and extension to lateral lung fields (see Tables 7-12 and 7-13)

FIGURE 7-14 Radiologic contours of the heart. AO, Aorta; IVC, inferior vena cava; LA, left atrium; LAA, left atrial appendage; LPA, left pulmonary artery; LV, left ventricle; PA, pulmonary artery; RA, right atrium; RPA, right pulmonary artery; RV, right ventricle; SVC, superior vena cava.

c. Venous congestion, or congestive heart failure (CHF): Increased PVMs centrally, interstitial and alveolar pulmonary edema (air bronchograms), septal lines, and pleural effusions (see Tables 7-12 and 7-13)

3. Evaluate the trachea: Usually bends slightly to the right above the carina in normal patients with a left-sided aortic arch. A perfectly straight or left-bending trachea suggests a right aortic arch, which may be associated with other defects (TOF, truncus arteriosus, vascular rings, chromosome 22 microdeletion).

4. Skeletal anomalies:

a. Rib notching (e.g., from collateral vessels in patients >5 years of age with coarctation of the aorta)

b. Sternal abnormalities (e.g., Holt-Oram syndrome, pectus excavatum in Marfan, Ehlers-Danlos, and Noonan syndromes)

c. Vertebral anomalies (e.g., VATER/VACTERL syndrome: Vertebral anomalies, Anal atresia, Tracheoesophageal fistula, Radial and Renal, Cardiac, and Limb anomalies)

B. Echocardiography

1. Approach:

a. Transthoracic echocardiography (TTE): Does not require general anesthesia, is simpler to perform than transesophageal echocardiography (TEE), but does have limitations in some patients (e.g., uncooperative, obese, or those with suspected endocarditis)

b. TEE: Uses an ultrasound transducer on the end of a modified endoscope to view the heart from the esophagus and stomach, allowing for better imaging of intracardiac structures. TEE allows for better imaging in obese and intraoperative patients and is also useful for visualizing very small lesions, such as some vegetations.

2. Shortening fraction: Very reliable index of left ventricular function. Normal values range from 30%–45%, depending on age.¹¹

C. Cardiac Catheterization

See Fig. EC 7-A for diagram of normal pressure values.

VI. Congenital Heart Disease

A. Pulse Oximetry Screening for Critical Congenital Heart Disease

2. Screening recommended on the right hand and on one foot, either in parallel or direct sequence.

3. Screening result would be considered positive if:

a. Any oxygen saturation measure is < 90%.

b. Oxygen saturation is <95% in both extremities on 3 measures, each separated by 1 hour.

3. Modes

a. M mode: Ice pick view—limited ability to show spatial structural relationship. Replaced by two-dimensional echo. Currently still used to measure dimensions of vessels and heart chambers, evaluate for pericardial effusion, assess valve motion, left ventricular (LV) systolic function.

b. Two-dimensional: Better demonstration of spatial structure relationship

c. Doppler: To demonstrate flow, cardiac output, and pressure gradients

d. Shortening fraction: Evaluates LV systolic function. Formula: FS (%) = Dd − Ds/Dd × 100 (Dd, End-diastolic dimension; Ds, end-systolic dimension). Normal value mean is 36%.

c. There is a >3% absolute difference in oxygen saturation between the right hand and foot on 3 measures, each separated by 1 hour.

B. Common Syndromes Associated with Cardiac Lesions (Table 7-11)

C. Acyanotic Lesions (Table 7-12)

D. Cyanotic Lesions (Table 7-13)

An oxygen challenge test is used to evaluate the etiology of cyanosis in neonates. Obtain baseline arterial blood gas (ABG) with saturation at FiO₂= 0.21, then place infant in an oxygen hood at FiO₂= 1 for a minimum of 10 min, and repeat ABG. In cardiac disease, there will not be a significant change in PaO₂ following the oxygen challenge test. Note: Pulse oximetry will not be useful for following the change in oxygenation once the saturations reach 100% (approximately PaO₂ >90 mmHg).^11-14

1. See Table EC 7-B for interpretation of oxygen challenge test.

2. Table 7-14 shows acute management of hypercyanotic spells in TOF.

TABLE 7-11

MAJOR SYNDROMES ASSOCIATED WITH CARDIAC DEFECTS

Syndrome	Dominant Cardiac Defect
CHARGE	TOF, truncus arteriosus, aortic arch abnormalities
DiGeorge	Aortic arch anomalies, TOF, truncus arteriosus, VSD, PDA
Trisomy 21	Atrioventricular septal defect, VSD
Marfan	Aortic root dilation, mitral valve prolapse
Loeys-Dietz	Aortic root dilation with higher risk of rupture at smaller dimensions
Noonan	Supravalvular pulmonic stenosis, LVH
Turner	COA, bicuspid aortic valve, aortic root dilation as a teenager
Williams	Supravalvular aortic stenosis, pulmonary artery stenosis
FAS	Occasional: VSD, PDA, ASD, TOF
IDM	TGA, VSD, COA, cardiomyopathy
VATER/VACTERL	VSD
VCFS	Truncus arteriosus, TOF, pulmonary atresia with VSD, TGA, interrupted aortic arch

ASD, Atrial septal defect; CHARGE, a syndrome of associated defects including Coloboma of the eye, Heart anomaly, choanal Atresia, Retardation, and Genital and Ear anomalies; COA, coarctation of aorta; FAS, fetal alcohol syndrome; IDM, infant of diabetic mother; LVH, left ventricular hypertrophy; PDA, patent ductus arteriosis; TGA, transposition of the great arteries; TOF, tetralogy of Fallot; VATER/VACTERL, association of Vertebral anomalies, Anal atresia, Cardiac anomalies, Tracheoesophageal fistula, Renal/radial anomalies, Limb defects; VCFS, velocardiofacial syndrome; VSD, ventricular septal defect.

Adapted from Park MK. Pediatric Cardiology for Practitioners. 5th ed. St Louis: Mosby; 2008:10-12.

TABLE EC 7-B

INTERPRETATION OF OXYGEN CHALLENGE TEST

Condition	FIO₂= 0.21 PaO₂ (% Saturation)		FIO₂= 1.00 PaO₂ (% Saturation)	PaCO₂
Normal	70 (95)		>200 (100)	35
Pulmonary disease	50 (85)		>150 (100)	50
Neurologic disease	50 (85)		>150 (100)	50
Methemoglobinemia	70 (85)		>200 (85)	35
Cardiac disease
• Separate circulation^∗	<40 (<75)		<50 (<85)	35
• Restricted PBF^†	<40 (<75)		<50 (<85)	35
• Complete mixing without restricted PBF^‡	50 (85)		<150 (<100)	35
Persistent pulmonary hypertension	Preductal	Postductal
PFO (no R–L shunt)	70 (95)	<40 (<75)	Variable	35–50
PFO (with R–L shunt)	<40 (<75)	<40 (<75)	Variable	35–50

PBF, Pulmonary blood flow; PFO, patent foramen ovale.

∗ D-Transposition of the great arteries (D-TGA) with intact ventricular septum.

† Tricuspid atresia with pulmonary stenosis or atresia, pulmonary atresia or critical pulmonary stenosis with intact ventricular septum, or tetralogy of Fallot.

‡ Truncus, total anomalous pulmonary venous return, single ventricle, hypoplastic left heart, D-TGA with ventricular septal defect, tricuspid atresia without pulmonary stenosis or atresia.

Adapted from Lees MH. Cyanosis of the newborn infant: Recognition and clinical evaluation. J Pediatr. 1970;77:484; Kitterman JA. Cyanosis in the newborn infant. Pediatr Rev. 1982;4:13; and Jones RW, Baumer JH, Joseph MC, et al. Arterial oxygen tension and response to oxygen breathing in differential diagnosis of heart disease in infancy. Arch Dis Child. 1976;51:667-673.

FIGURE 7-15 Schematic diagram of cardiac shunts.

TABLE 7-12

ACYANOTIC CONGENITAL HEART DISEASE

Lesion Type	% of CHD/Examination Findings	CDG Findings	Chest Radiograph Findings
Ventricular septal defect (VSD)	2–5/6 holosystolic murmur, loudest at the LLSB, ± systolic thrill ± apical diastolic rumble with large shunt With large VSD and pulmonary hypertension, S₂ may be narrow	Small VSD: Normal Medium VSD: LVH ± LAE Large VSD: BVH ± LAE, pure RVH	May show cardiomegaly and increased PVMs, depending on amount of left-to-right shunting
Atrial septal defect (ASD)	Wide, fixed split S₂ with grade 2–3/6 SEM at the LUSB May have mid-diastolic rumble at LLSB	Small ASD: Normal Large ASD: RAD and mild RVH or RBBB with RSR′ in V₁	May show cardiomegaly with increased PVMs if hemodynamically significant ASD
Patent ductus arteriosus (PDA)	40%–60% in VLBW infants 1–4/6 continuous “machinery” murmur loudest at LUSB Wide pulse pressure	Small–moderate PDA: Normal or LVH Large PDA: BVH	May have cardiomegaly and increased PVMs, depending on size of shunt (see Chapter 18 Section IX.A for treatment)
Atrioventricular septal defects	Most occur in Down syndrome Hyperactive precordium with systolic thrill at LLSB and loud S₂ ± grade 3–4/6 holosystolic regurgitant murmur along LLSB ± systolic murmur of MR at apex ± mid-diastolic rumble at LLSB or at apex ± gallop rhythm	Superior QRS axis RVH and LVH may be present	Cardiomegaly with increased PVMs
Pulmonary stenosis (PS)	Ejection click at LUSB with valvular PS—click intensity varies with respiration, decreasing with inspiration and increasing with expiration S₂ may split widely with P₂ diminished in intensity SEM (2–5/6) ± thrill at LUSB with radiation to back and sides	Mild PS: Normal Moderate PS: RAD and RVH Severe PS: RAE and RVH with strain	Normal heart size with normal to decreased PVMs
Aortic stenosis (AS)	Systolic thrill at RUSB, suprasternal notch, or over carotids Ejection click that does not vary with respiration if valvular AS Harsh SEM (2–4/6) at second RICS or third LICS, with radiation to neck and apex ± early diastolic decrescendo murmur due to AR Narrow pulse pressure if severe stenosis	Mild AS: Normal Moderate–severe AS: LVH ± strain	Usually normal
Table Continued

Lesion Type	% of CHD/Examination Findings	CDG Findings	Chest Radiograph Findings
Coarctation of aorta may present as: 1. Infant in CHF 2. Child with HTN 3. Child with murmur	Male/female ratio of 2:1 2–3/6 SEM at LUSB, radiating to left interscapular area Bicuspid valve is often associated, so may have systolic ejection click at apex and RUSB BP in lower extremities will be lower than in upper extremities. Pulse oximetry discrepancy of >5% between upper and lower extremities is also suggestive of coarctation.	In infancy: RVH or RBBB In older children: LVH	Marked cardiomegaly and pulmonary venous congestion. Rib notching from collateral circulation usually not seen in children younger than 5 years because collaterals not yet established.

AR, Aortic regurgitation; ASD, atrial septal defect; BP, blood pressure; BVH, biventricular hypertrophy; CHD, congenital heart disease; CHF, congestive heart failure; HTN, hypertension; LAE, left atrial enlargement; LICS, left intercostal space; LLSB, left lower sternal border; LUSB, left upper sternal border; LVH, left ventricular hypertrophy; MR, mitral regurgitation; PVM, pulmonary vascular markings; RAD, right axis deviation; RAE, right atrial enlargement; RBBB, right bundle-branch block; RICS, right intercostal space; RUSB, right upper sternal border; RVH, right ventricular hypertrophy; SEM, systolic ejection murmur; VLBW, very low birth weight (i.e. <1500 g); VSD, ventricular septal defect.

TABLE 7-13

CYANOTIC CONGENITAL HEART DISEASE

Lesion	Examination Findings	ECG Findings	Chest Radiograph Findings
Tetralogy of Fallot: 1. Large VSD 2. RVOT obstruction 3. RVH 4. Overriding aorta Degree of RVOT obstruction will determine whether there is clinical cyanosis. If PS is mild, there will be a left-to-right shunt, and child will be acyanotic. Increased obstruction leads to increased right-to-left shunting across VSD, and child will be cyanotic.	Loud SEM at LMSB and LUSB and a loud, single S₂ ± thrill at LMSB and LLSB. Tet spells: Occur in young infants. As RVOT obstruction increases or systemic resistance decreases, right-to-left shunting across VSD occurs. May present with tachypnea, increasing cyanosis, and decreasing murmur. See Table 7-14 for treatment.	RAD and RVH	Boot-shaped heart with normal heart size ± decreased PVMs
Table Continued

Lesion	Examination Findings	ECG Findings	Chest Radiograph Findings
Transposition of great arteries	Nonspecific. Extreme cyanosis. Loud, single S₂. No murmur unless there is associated VSD or PS.	RAD and RVH (due to RV acting as systemic ventricle). Upright T wave in V₁ after age 3 days may be only abnormality.	Classic finding: “egg on a string” with cardiomegaly; possible increased PVMs
Tricuspid atresia: Absent tricuspid valve and hypoplastic RV and PA. Must have ASD, PDA, or VSD to survive.	Single S₂ + grade 2–3/6 systolic regurgitation murmur at LLSB if VSD is present. Occasional PDA murmur.	Superior QRS axis; RAE or CAE and LVH	Normal or slightly enlarged heart size; may have boot-shaped heart
Total anomalous pulmonary venous return Instead of draining into LA, pulmonary veins drain into the following locations. Must have ASD or PFO for survival: 1. Supracardiac (most common): SVC 2. Cardiac: Coronary sinus or RA 3. Subdiaphragmatic: IVC, portal vein, ductus venosus, or hepatic vein 4. Mixed type	Hyperactive RV impulse, quadruple rhythm, S₂ fixed and widely split, 2–3/6 SEM at LUSB, and mid-diastolic rumble at LLSB	RAD, RVH (RSR′ in V₁). May see RAE	Cardiomegaly and increased PVMs; classic finding is “snowman in a snowstorm,” but this is rarely seen until after age 4 months.
OTHER
Cyanotic CHDs that occur at a frequency of <1% each include pulmonary atresia, Ebstein anomaly, truncus arteriosus, single ventricle, and double outlet right ventricle

ASD, Atrial septal defect; CAE, common atrial enlargement; ECG, electrocardiogram; IVC, inferior vena cava; LA, left atrium; LLSB, left lower sternal border; LMSB, left mid-sternal border; LUSB, left upper sternal border; LVH, left ventricular hypertrophy; PA, pulmonary artery; PDA, patent ductus arteriosus; PFO, patent foramen ovale; PVM, pulmonary vascular markings; PS, pulmonary stenosis; RA, right atrium; RAD, right-axis deviation; RAE, right atrial enlargement; RV, right ventricle; RVH, right ventricular hypertrophy; RVOT, right ventricular outflow tract; SEM, systolic ejection murmur; SVC, superior vena cava; VSD, ventricular septal defect.

TABLE 7-14

TREATMENT OPTIONS FOR TET SPELLS

Treatment	Rationale
INITIAL OPTIONS
Calm child	Decreases PVR
Encourage knee-chest position	Decreases venous return and increases SVR
Oxygen	Reduces hypoxemia, decreases PVR
Intravenous fluids	Provides volume resuscitation
Morphine (morphine sulfate 0.1–0.2 mg/kg SQ or IM)	Decreases venous return, decreases PVR, relaxes infundibulum. Do not try to establish IV access initially; use SQ route.
IF THERE IS NO RESPONSE TO INITIAL MEASURES
Phenylephrine (0.02 mg/kg IV)	Increases SVR
Propranolol (0.01–0.25 mg/kg slow IV push)	Has negative inotropic effect on infundibular myocardium; may block drop in SVR
Ketamine 1–3 mg/kg	Increases SVR and sedates
OTHER
Correct anemia	Increases delivery of oxygen to tissues
Correct pathologic tachyarrhythmias	May abort hypoxic spell
Infuse glucose	Avoids hypoglycemia from increased utilization and depletion of glycogen stores

IM, Intramuscular; IV, intravenous; PVR, peripheral venous resistance; SQ, subcutaneous; SVR, systemic vascular resistance.

From Park MK. Pediatric Cardiology for Practitioners. 5th ed. St Louis: Mosby; 2008:239.

E. Surgeries and Other Interventions (Fig. 7-15)

1. Atrial septostomy: Creates an intra-atrial opening to allow for mixing or shunting between atria of systemic and pulmonary venous blood. Used for transposition of the great arteries (TGA), tricuspid, mitral, tricuspid and pulmonary atresia, and sometimes total anomalous pulmonary venous return. Most commonly performed percutaneously with a balloon-tipped catheter (Rashkind procedure).

2. Palliative systemic-to–pulmonary artery shunts, such as the Blalock-Taussig shunt (subclavian artery to pulmonary artery [PA]): Use systemic arterial flow to increase pulmonary blood flow in cardiac lesions with impaired pulmonary perfusion (e.g., TOF, hypoplastic right heart, tricuspid atresia, pulmonary atresia)

3. Palliative superior vena cava–to–pulmonary artery shunts, such as the Glenn shunt, also known as the hemi-Fontan (superior vena cava [SVC] to the right pulmonary artery [RPA]): Directs a portion of the systemic venous return directly into the pulmonary blood flow as an intermediate step to a Fontan procedure. This procedure is usually performed outside the neonatal period, when there is lower pulmonary vascular resistance.

4. Fontan procedure: Performed after the Glenn shunt; involves anastomosis of the right atria and/or inferior vena cava (IVC) to pulmonary arteries via conduits; separates systemic and pulmonary circulations in patients with functionally single ventricles (tricuspid atresia, hypoplastic left heart syndrome)

5. Norwood procedure: Used for hypoplastic left heart syndrome

a. Stage 1 (neonatal period): To provide systemic blood flow, anastomosis of the proximal main pulmonary artery (MPA) is made to the aorta, with aortic arch reconstruction and patch closure of the distal MPA. To provide pulmonary blood flow, a modified right Blalock-Taussig shunt (subclavian artery to RPA) or Sano modification (RV to PA conduit) is performed. An atrial septal defect is created if needed to decompress the left atrium and allow for adequate left-to-right flow. Expected O₂ saturations: 75%–85%.

b. Stage 2 (3–6 months of age): Bidirectional Glenn shunt or hemi-Fontan to reduce volume overload of single right ventricle. Expected O₂ saturations: 80%–85%.

c. Modified Fontan (age 18 mo–4 yr): Needed to completely separate systemic and pulmonary circulations. Restores normal O₂ saturation, with expected O₂ saturation >92%.

6. Arterial switch procedure: Used for repair of TGA. Connects aorta to left ventricle and pulmonary artery to right ventricle. Procedure also involves reconnecting coronary arteries to aorta.

7. Ross procedure: Pulmonary root autograft for aortic stenosis; autologous pulmonary valve replaces aortic valve, and aortic or pulmonary allograft replaces pulmonary valve.

VII. Acquired Heart Disease

A. Endocarditis

1. Common causative organisms: About 70% of causes of endocarditis are streptococcal species (Streptococcus viridans, enterococci); 20% are staphylococcal species (Staphylococcus aureus, Staphylococcus epidermidis); 10% are other organisms (Haemophilus influenzae, gram-negative bacteria, fungi).

2. Clinical findings: New heart murmur, recurrent fever, splenomegaly, petechiae, fatigue, Osler nodes (tender nodules at fingertips), Janeway lesions (painless hemorrhagic areas on palms or soles), splinter hemorrhages, and Roth spots (retinal hemorrhages)

B. Bacterial Endocarditis Prophylaxis

See Table 7-15 for antibiotic choices and Box 7-4 for cardiac conditions requiring prophylaxis.¹⁵

1. All dental procedures that involve treatment of gingival tissue or periapical region of the teeth or oral mucosal perforation

2. Invasive procedures that involve incision or biopsy of respiratory mucosa, such as tonsillectomy and adenoidectomy

3. Not recommended for genitourinary or gastrointestinal tract procedures; solely for bacterial endocarditis prevention

C. Myocardial Disease

1. Dilated cardiomyopathy: End result of myocardial damage, leading to atrial and ventricular dilation with decreased systolic contractile function of the ventricles

a. Etiology: Infectious, toxic (alcohol, anthracyclines), metabolic (hypothyroidism, muscular dystrophy), immunologic, collagen vascular disease, nutritional deficiency (kwashiorkor, beriberi)

b. Symptoms: Fatigue, weakness, shortness of breath

c. Examination: Look for signs of CHF(e.g., tachycardia, tachypnea, rales, cold extremities, jugular venous distention, hepatomegaly, peripheral edema, S₃ gallop, displacement of point of maximal impulse to the left and inferiorly)

d. Chest radiograph: Generalized cardiomegaly, pulmonary congestion

e. ECG: Sinus tachycardia, left ventricular hypertrophy (LVH), possible atrial enlargement, arrhythmias, conduction disturbances, ST-segment and T-wave changes

TABLE 7-15

PROPHYLACTIC REGIMENS FOR DENTAL AND RESPIRATORY TRACT PROCEDURES

Drug	Dosing^∗ (not to exceed adult dose)
Amoxicillin^†	Adult: 2 g; Child: 50 mg/kg PO
Ampicillin	Adult: 2 g; Child: 50 mg/kg IM/IV
Cefazolin or ceftriaxone^‡	Adult: 1 g; Child: 50 mg/kg IM/IV
Cephalexin^‡	Adult: 2 g; Child: 50 mg/kg PO
Clindamycin	Adult: 600 mg; Child: 20 mg/kg PO/IM/IV
Azithromycin/clarithromycin	Adult: 500 mg; Child:15 mg/kg PO

∗ Oral (PO) medications should be given 1 hour before procedure; intramuscular/intravenous (IM/IV) medications should be given within 30 min prior to procedure.

† Standard general prophylaxis.

‡ Cephalosporins should not be used in persons with intermediate-type hypersensitivity reaction to penicillins or ampicillin.

Adapted from Wilson W, Taubert KA, Gewitz M, et al. Prevention of infectiveendocarditis: Guidelines from the American Heart Association: A guideline from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Circulation. 2007;116:1736-1754.

BOX 7-4 CARDIAC CONDITIONS FOR WHICH ANTIBIOTIC PROPHYLAXIS IS RECOMMENDED FOR DENTAL, RESPIRATORY TRACT, INFECTED SKIN, SKIN STRUCTURES, OR MUSCULOSKELETAL TISSUE PROCEDURES

• Prosthetic cardiac valve

• Previous bacterial endocarditis

• Congenital heart disease (CHD)—Limited to the following conditions ^∗

• Unrepaired cyanotic defect, including palliative shunts and conduits

• Completely repaired CHD with prosthetic material/device (placed by surgery or catheterization), during first 6 months after procedure^†

• Repaired CHD with residual defects at or adjacent to the site of prosthetic patch or device (which inhibit endothelialization)

• Cardiac transplantation patients who develop cardiac valvulopathy

^∗ Conditions associated with the highest risk of adverse outcome from endocarditis.

† Endothelialization process of prosthetic material occurs within 6 months after the procedure.

Adapted from Wilson W, Taubert KA, Gewitz M, et al. Prevention of infective endocarditis: Guidelines from the American Heart Association: A guideline from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Circulation. 2007;116:1736-1754.

f. Echocardiography: Enlarged ventricles (increased end-diastolic and end-systolic dimensions) with little or no wall thickening; decreased shortening fraction

g. Treatment: Management of CHF (digoxin, diuretics, vasodilation, angiotensin-converting enzyme [ACE] inhibitors, rest). Consider anticoagulants to decrease risk for thrombus formation.

2. Hypertrophic cardiomyopathy: Abnormality of myocardial cells leading to significant ventricular hypertrophy, particularly of left ventricle, with small to normal ventricular dimensions. Increased contractile function but impaired filling secondary to stiff ventricles. The most common type is asymmetrical septal hypertrophy, also called idiopathic hypertrophic subaortic stenosis (IHSS), with varying degrees of obstruction. A 4%–6% incidence of sudden death in children and adolescents with hypertrophic obstructive cardiomyopathy (HOCM).

a. Etiology: Genetic (autosomal dominant, 60% of cases) or sporadic (40% of cases)

b. Symptoms: Easy fatigability, anginal pain, shortness of breath, occasional palpitations

c. Examination: Usually in adolescents or young adults; signs include left ventricular heave, sharp upstroke of arterial pulse, murmur of mitral regurgitation, midsystolic ejection murmur along left midsternal border (LMSB) that increases in intensity in the standing position (in patients with midcavity left ventricular obstruction)

d. Chest radiograph: Globular-shaped heart with left ventricular enlargement

e. ECG: LVH, prominent Q waves (septal hypertrophy), ST-segment and T-wave changes, arrhythmias

f. Echocardiography: Extent and location of hypertrophy, obstruction, increased contractility

g. Treatment: Moderate restriction of physical activity, administration of negative inotropes (β-blocker, calcium channel blocker) to help improve filling and subacute bacterial endocarditis prophylaxis. If at increased risk for sudden death, may consider implantable defibrillator. If symptomatic with subaortic obstruction, may benefit from myectomy.

3. Restrictive cardiomyopathy: Myocardial or endocardial disease (usually infiltrative or fibrotic) resulting in stiff ventricular walls, with restriction of diastolic filling but normal contractile function. Results in atrial enlargement. Associated with a high mortality rate. Very rare in children.

a. Etiology: Scleroderma, amyloidosis, sarcoidosis, mucopolysaccharidosis

b. Treatment: Supportive, poor prognosis. Diuretics, anticoagulants, calcium channel blockers, pacemaker for heart block, cardiac transplantation if severe.

4. Myocarditis: Inflammation of myocardial tissue

a. Etiology: Viral (coxsackievirus, echovirus, adenovirus, poliomyelitis, mumps, measles, rubella, cytomegalovirus, HIV, arbovirus, influenza); bacterial, rickettsial, fungal, or parasitic infection; immune-mediated disease (Kawasaki disease, acute rheumatic fever); collagen vascular disease; toxin-induced

b. Symptoms: Nonspecific and inconsistent, depending on severity of disease. Variably anorexia, lethargy, emesis, lightheadedness, cold extremities, shortness of breath.

c. Examination: Look for signs of CHF (tachycardia, tachypnea, jugular venous distention, rales, gallop, hepatomegaly); occasionally a soft systolic murmur or arrhythmia may be noted.

d. Chest radiograph: Variable cardiomegaly and pulmonary edema

e. ECG: Low QRS voltages throughout (<5 mm), ST-segment and T-wave changes (e.g., decreased T-wave amplitude), prolongation of QT interval, arrhythmias (especially premature contractions, first- or second-degree AV block)

f. Laboratory tests: CK, troponin

g. Echocardiography: Enlargement of heart chambers, impaired left ventricular function

h. Treatment: Bed rest, diuretics, inotropes (dopamine, dobutamine, milrinone), digoxin, gamma globulin (2 g/kg over 24 hours), ACE inhibitors, possibly steroids. May require heart transplantation if no improvement (≈20%–25% of cases)

D. Pericardial Disease

1. Pericarditis: Inflammation of visceral and parietal layers of pericardium

a. Etiology: Viral (especially echovirus, coxsackievirus B), tuberculosis, bacterial, uremic, neoplastic, collagen vascular, post-MI or postpericardiotomy, radiation induced, drug induced (e.g., procainamide, hydralazine), or idiopathic

b. Symptoms: Chest pain (retrosternal or precordial, radiating to back or shoulder, pleuritic in nature, alleviated by leaning forward, aggravated by supine position), dyspnea

c. Examination: Pericardial friction rub, distant heart sounds, fever, tachypnea

d. ECG: Diffuse ST-segment elevation in almost all leads (representing inflammation of adjacent myocardium); PR-segment depression

e. Treatment: Often self-limited. Treat underlying condition and provide symptomatic treatment with rest, analgesia, and antiinflammatory drugs

2. Pericardial effusion: Accumulation of excess fluid in pericardial sac

a. Etiology: Associated with acute pericarditis (exudative fluid) or serous effusion resulting from increased capillary hydrostatic pressure (e.g., CHF), decreased plasma oncotic pressure (e.g., hypoproteinemia), and increased capillary permeability (transudative fluid)

b. Symptoms: Can present with no symptoms, dull ache in left chest, abdominal pain, or symptoms of cardiac tamponade (see later)

c. Examination: Muffled distant heart sounds, dullness to percussion of posterior left chest (secondary to atelectasis from large pericardial sac), hemodynamic signs of cardiac compression

d. Chest radiograph: Globular symmetrical cardiomegaly

e. ECG: Decreased voltage of QRS complexes, electrical alternans (variation of QRS axis with each beat secondary to swinging of heart within pericardial fluid)

f. Echocardiography shows extent and location of hypertrophy, obstruction, increased contractility

g. Treatment: Address underlying condition. Observe if asymptomatic; use pericardiocentesis if there is sudden increase in volume or hemodynamic compromise. Nonsteroidal antiinflammatory drugs (NSAIDs) or steroids may be of benefit, depending on etiology.

3. Cardiac tamponade: Accumulation of pericardial fluid under high pressure, causing compression of cardiac chambers, limiting filling, and decreasing stroke volume and cardiac output

a. Etiology: Same as pericardial effusion; most commonly associated with viral infection, neoplasm, uremia, and acute hemorrhage

b. Symptoms: Dyspnea, fatigue, cold extremities

c. Examination: Jugular venous distention, hepatomegaly, peripheral edema, tachypnea, rales (from increased systemic and pulmonary venous pressure), hypotension, tachycardia, pulsus paradoxus (decrease in systolic blood pressure by >10 mmHg with each inspiration), decreased capillary refill (from decreased stroke volume and cardiac output), quiet precordium, and muffled heart sounds

d. ECG: Sinus tachycardia, decreased voltage, electrical alternans

e. Echocardiography: Right ventricle collapse in early diastole, right atrial/left atrial collapse in end-diastole and early systole

f. Treatment: Pericardiocentesis with temporary catheter left in place if necessary (see Chapter 3, Figs. 3-15 and 3-16); pericardial window or stripping if it is a recurrent condition

E. Kawasaki Disease

Acute febrile vasculitis of unknown etiology, common in children < 8 years of age, and the leading cause of acquired heart disease in children in developed countries

1. Etiology: Unknown; thought to be immune regulated in response to infectious agents or environmental toxins

2. Diagnosis:

a. Typical Kawasaki disease: Based on clinical criteria. These include high fever lasting 5 days or more, plus at least 4 of the following 5 criteria:

(1) Bilateral painless bulbar conjunctival injection without exudate

(2) Erythematous mouth and pharynx, strawberry tongue, or red cracked lips

(3) Polymorphous exanthem (may be morbilliform, maculopapular, or scarlatiniform)

(4) Swelling of hands and feet, with erythema of palms and soles

(5) Cervical lymphadenopathy (>1.5 cm in diameter), usually single and unilateral

b. Atypical/incomplete Kawasaki disease: A suspicion of Kawasaki but with fewer of the criteria required for diagnosis. Even without all criteria, there is a risk for coronary artery abnormalities.

(1) More often seen in infants. Echocardiography should be considered in any infant < 6 months with fever > 7 days duration, laboratory evidence of systemic inflammation, and no other explanation for the febrile illness.

(2) See Fig. 7-16 for evaluation of incomplete Kawasaki disease.

(3) Supplemental laboratory criteria: Albumin ≤ 3.0 g/dL, anemia for age, elevation of alanine aminotransferase, platelets after 7 days ≥ 450,000 / mm³, white blood cell count ≥ 15,000 / mm³, and urine white blood cells/hpf ≥ 10.

3. Other clinical findings: Often associated with extreme irritability, abdominal pain, diarrhea, vomiting. Also seen are arthritis and arthralgias, hepatic enlargement, jaundice, acute acalculous distention of the gallbladder, carditis, aseptic meningitis (50% of those undergoing LP).

4. Laboratory findings: Leukocytosis with left shift, neutrophils with vacuoles or toxic granules, elevated C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR) (seen acutely), thrombocytosis (after first week, peaking at 3 weeks), normocytic and normochromic anemia, sterile pyuria (33%), increased transaminases (40%), hyperbilirubinemia (10%)

5. Subacute phase (11–25 days after onset of illness): Resolution of fever, rash, and lymphadenopathy. Often, desquamation of the fingertips or toes and thrombocytosis occur.

Cardiovascular complications: If untreated, 20%–25% develop coronary artery aneurysms and dilation in subacute phase (peak prevalence occurs about 2–4 weeks after onset of disease; rarely appears after 6 weeks) and are at risk for coronary thrombosis acutely and coronary stenosis chronically. Carditis; aortic, mitral, and tricuspid regurgitation; pericardial effusion; CHF; MI; left ventricular dysfunction; and ECG changes may also occur.

FIGURE 7-16 Evaluation of incomplete Kawasaki disease (KD). CRP, C-reactive protein; echo, echocardiogram; ESR, erythrocyte sedimentation rate; f/u, follow-up. (From Newburger JW, Takahashi M, Gerber MA, et al. Diagnosis, treatment, and long term management of Kawasaki disease. Circulation. 2004;110:2747-2771.)

6. Convalescent phase: ESR, CRP, and platelet count return to normal. Those with coronary artery abnormalities are at increased risk for MI, arrhythmias, and sudden death.

7. Management (also see Table EC 7-C)¹⁶

a. Intravenous immunoglobulin (IVIG)

(1) Shown to reduce incidence of coronary artery dilation to <3% and decrease duration of fever if given in the first 10 days of illness. Current recommended regimen is a single dose of IVIG, 2 g/kg over 10–12 hours.

TABLE EC 7-C

GUIDELINES FOR TREATMENT AND FOLLOW-UP OF CHILDREN WITH KAWASAKI DISEASE

Risk Level	Pharmacologic Therapy	Physical Activity	Follow-up and Diagnostic Testing	Invasive Testing
I: No coronary artery changes at any stage of illness	None beyond initial 6–8 weeks	No restrictions beyond initial 6–8 weeks	Counsel on cardiovascular risk factors every 5 years	None recommended
II: Transient coronary artery ectasia that resolves by 8 weeks after disease onset	None beyond initial 6–8 weeks	No restrictions beyond initial 6–8 weeks	Counsel on cardiovascular risk factors every 3–5 years	None recommended
III: Small to medium solitary coronary artery aneurysm	3–5 mg/kg/day aspirin, at least until aneurysm resolves	For patients in first decade of life, no restriction beyond initial 6–8 weeks; during second decade of life, physical activity guided by stress testing every 2 years; avoid competitive contact and high-impact sports while on antiplatelet therapy	Annual follow-up with echocardiogram and ECG	Angiography if stress testing or echocardiography suggests stenosis
IV: One or more large (>6 mm)aneurysms and coronary arteries with multiple small to medium aneurysms, without obstruction	Long-term aspirin (3–5 mg/kg/day) and warfarin or LMWH for patients with giant aneurysms	Annual stress testing guides physical activity; avoid competitive contact and high-impact sports while on anticoagulant therapy	Echocardiogram and ECG at 6-mo intervals, annual stress testing, atherosclerosis risk factor counseling at each visit	Cardiac catheterization 6–12 months after acute illness,with additional testing if ischemia noted or testing inconclusive
V: Coronary artery obstruction	Long-term aspirin (3–5 mg/kg/day); warfarin or LMWH if giant aneurysm persists; consider use of β-blockers to reduce myocardial work	Contact sports, isometrics, and weight training should be avoided; other physical activity recommendations guided by outcome of stress testing or myocardial perfusion scan	Echocardiogram and ECG at 6-mo intervals, annual Holter and stress testing	Cardiac catheterization 6–12 months after acute illness to aid in selecting therapeutic options, additional testing if ischemia noted

LMWH, Low molecular weight heparin.

(2) Some 10% of patients treated with IVIG fail to respond (persistent or recurrent fever ≥36 hr after IVIG completion). Re-treat with second dose.

b. Aspirin is recommended for both its antiinflammatory and antiplatelet effects. American Heart Association (AHA) recommends initial high-dose aspirin (80–100 mg/kg/day divided in four doses) until 48–72 hours after defervescence. Given with IVIG. Then continue with low-dose aspirin (3–5 mg/kg/day as a single daily dose) for 6–8 weeks or until platelet count and ESR are normal (if there are no coronary artery abnormalities) or indefinitely if coronary artery abnormalities persist.

c. Dipyridamole, 4 mg/kg divided in three doses, is sometimes used as an alternative to aspirin, particularly if symptoms of influenza or varicella arise while on aspirin (concern for Reye syndrome).

d. Follow-up: Serial echocardiography is recommended to assess coronary arteries and left ventricular function (at time of diagnosis, at 2 weeks, at 6–8 weeks, and at 12 months [optional]). More frequent intervals and long-term follow-up are recommended if abnormalities are seen on echocardiography. Cardiac catheterization may be necessary.

F. Rheumatic Heart Disease

1. Etiology: Believed to be immunologically mediated delayed sequela of group A streptococcal pharyngitis

2. Clinical findings: History of streptococcal pharyngitis 1–5 weeks before onset of symptoms. Often with pallor, malaise, easy fatigability.

3. Diagnosis: Jones criteria (Box 7-5)

4. Management: Penicillin, bed rest, salicylates, supportive management of CHF (if present) with diuretics, digoxin, morphine

G. Lyme Disease

1. Etiology: Following infection with Borrelia burgdorferi

2. Clinical symptoms: About 8%–10% of patients will get AV block. Other possible cardiac symptoms include myocarditis and pericarditis.

VIII. Exercise Recommendations for Congenital Heart Disease

See Table EC 7-D for exercise recommendations for congenital heart disease.^,¹⁷

IX. Lipid Monitoring Recommendations

A. Screening of Children and Adolescents ¹⁸

1. Universal screening of non-fasting non-HDL cholesterol in children 9–11 years old (prior to onset of puberty) and again in individuals 17–21 years

2. Targeted screening should occur in children 2–8 years old and adolescents 12–16 years old, with two fasting lipid profiles (between 2 weeks and 3 months apart, results averaged) for the following risk factors:

a. Moderate or high-risk medical condition (history of prematurity, VLBW, congenital heart disease (repaired or nonrepaired), recurrent urinary

TABLE EC 7-D

EXERCISE RECOMMENDATIONS FOR CONGENITAL HEART DISEASE AND SPORTS ALLOWED FOR SOME SPECIFIC CARDIAC LESIONS ¹⁵

Diagnosis	Sports Allowed
Small ASD or VSD	All
Mild aortic stenosis	All
MVP (without other risk factors)	All
Moderate aortic stenosis	IA, IB, IIA
Mild LV dysfunction	IA, IB, IC
Moderate LV dysfunction	IA only
Long QT syndrome	IA only
Hypertrophic cardiomyopathy	None (or IA only)
Severe aortic stenosis	None

Sports Classification	Low Dynamic (A)	Moderate Dynamic (B)	High Dynamic (C)
I. Low static	Billiards Bowling Golf Riflery	Baseball/softball Table tennis Volleyball Fencing	Racket sports Cross-country skiing Field hockey^∗ Race walking Running (long distance) Soccer^∗
II. Moderate static	Archery Auto racing^∗,† Diving^∗,† Equestrian^∗,† Motorcycling^∗,†	Fencing Field events (jumping) Figure skating^∗ Football (American)^∗ Surfing Rugby^∗ Running (sprint) Synchronized swim†	Basketball^∗ Ice hockey^∗ Cross-country skiing (skating technique) Swimming Lacrosse^∗ Running (middle distance) Team handball
III. High static	Bobsledding Field events Gymnastics^∗,† Rock climbing Sailing Windsurfing^∗,† Waterskiing^∗,† Weight lifting^∗,†	Body building^∗,† Downhill skiing^∗,† Skateboarding^∗,†	Boxing/wrestling^∗ Martial arts^∗ Rowing Speed skating Cycling^∗,†

ASD, Atrial septal defect; LV, left ventricular; MVP, mitral valve prolapse; VSD, ventricular septal defect.

∗ Danger of bodily collision.

† Increased risk if syncope occurs.

Adapted from Maron BJ, Zipes DP. 36th Bethesda Conference: Eligibility recommendations for competitive athletes with cardiovascular abnormalities. J Am Coll Cardiol. 2005;45:1313-1375; and Committee on Sports Medicine and Fitness, American Academy of Pediatrics. Medical conditions affecting sports participation. Pediatrics. 2001;107:1205-1209.

BOX 7-5 GUIDELINES FOR DIAGNOSIS OF INITIAL ATTACK OF RHEUMATIC FEVER (JONES CRITERIA)

Major Manifestations	Minor Manifestations
Carditis	Clinical findings:
Polyarthritis	Arthralgia
Chorea	Fever
Erythema marginatum	Laboratory findings:
Subcutaneous nodule	Elevated acute phase reactants (erythrocyte sedimentation rate, C-reactive protein)
	Prolonged PR interval
Plus
Supporting evidence of antecedent group A streptococcal infection
Positive throat culture or rapid streptococcal antigen test
Elevated or rising streptococcal antibody titer

NOTE: If supported by evidence of preceding group A streptococcal infection, the presence of two major manifestations or of one major and two minor manifestations indicates a high probability of acute rheumatic fever.

tract infections, known renal or urologic malformations, family history of congenital renal disease, solid organ transplant, malignancy or bone marrow transplant, treatment with drugs known to raise blood pressure, other systemic illness associated with hypertension (neurofibromatosis, tuberous sclerosis), evidence of elevated intracranial pressure

b. Have other cardiovascular risk factors (diabetes, hypertension, body mass index [BMI] ≥ 95th percentile, smoke cigarettes)

c. Have a family history of early cardiovascular disease (CVD) or severe hypercholesterolemia

(1) Parent or grandparent who is < 55 years old (males) or < 65 years old (females) and had suffered a myocardial infarction or sudden death, undergone a coronary artery procedure, or who otherwise had evidence of coronary atherosclerosis, peripheral vascular disease, or cerebrovascular disease

(2) Parent with total cholesterol ≥ 240 mg/dL or known dyslipidemia

B. Goals for Lipid Levels in Childhood

1. Total cholesterol

a. Acceptable (<170 mg/dL): Repeat measurement in 3–5 years

b. Borderline (170–199 mg/dL): Repeat cholesterol and average with previous measurement. If <170, repeat in 3–5 years. If ≥170, obtain lipoprotein analysis.

c. High (≥200 mg/dL): Obtain lipoprotein analysis

2. Low-density lipoprotein (LDL) cholesterol

a. Acceptable (<110 mg/dL)

b. Borderline (110–129 mg/dL)

c. High (≥130 mg/dL)

C. Management of Hyperlipidemia ¹⁸

1. Normal and borderline elevated LDL levels: Education, risk factor intervention including diet, smoking cessation, and an exercise program. For borderline levels, reevaluate in 1 year.

2. High LDL levels: Examine for secondary causes (liver, thyroid, renal disorders) and familial disorders. Initiate low-fat, low-cholesterol diet; reevaluate in 6 months. Note: For LDL cholesterol > 250 or triglyceridemia >500, refer directly to a lipid specialist.

3. Drug therapy: Should be considered in children >10 years of age after failure of 6- to 12-month trial of diet therapy as follows:

a. LDL >190 mg/dL without other cardiovascular disease risk factors

b. LDL >160 mg/dL with risk factors (diabetes, obesity, hypertension, positive family history of premature CVD)

c. LDL >130 mg/dL in children with diabetes mellitus

d. Bile acid sequestrants and statins are the usual first-line drugs for treatment in children.

4. Persistently high triglycerides (>150 mg/dL) and reduced HDL (<35 mg/dL): Evaluate for secondary causes (diabetes, alcohol abuse, renal or thyroid disease). Treatment is diet and exercise.