Harriet Lane Handbook by John Hopkins Hosipital 19e 9780323079426_sample chapter ch7

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Harriet Lane Handbook by John Hopkins Hosipital 19e 9780323079426_sample chapter ch7

  1. 1. Chapter 7CardiologyElaine Giannakos Lennox, MD See additional content on Expert Consult I. WEBSITESHeart and stroke encyclopedia: http://www.americanheart.orghttp://www.cincinnatichildrens.org/health/heart-encyclopedia/anomalies/http://www.pted.orghttp://www.murmurlab.org II. THE CARDIAC CYCLE (FIG. 7-1) III. PHYSICAL EXAMINATIONA. Blood Pressure1. 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 arteryb. Pulsus paradoxus: An exaggeration of the normal drop in systolic blood pressure (SBP) seen with inspiration. Determine the 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 cardiomyopathiesc. Blood pressure norms1,2: Tables 7-1 and 7-2; Figures 7-2 and 7-32. Pulse pressure = systolic pressure − diastolic pressurea. Wide pulse pressure (>40 mmHg): Differential diagnosis includes aortic insufficiency, arteriovenous fistula, patent ductus arteriosus, thyrotoxicosisb. Narrow pulse pressure (<25 mmHg): Differential diagnosis includes aortic stenosis, pericardial effusion, pericardial tamponade, pericarditis, significant tachycardia3. Mean arterial pressure (MAP) = diastolic pressure + (pulse pressure/3). In preterm infants and newborns, generally a normal MAP = gestational age in weeks + 5See Figure 7-4 for systolic blood pressure norms in preterm infantsB. Heart Sounds1. S1: Associated with closure of mitral and tricuspid valves; best heard at the apex or left lower sternal border (LLSB) Text continued on page 164154
  2. 2. Chapter 7 Cardiology 155 LV 120 Ao Intracardiac pressures 100 80 7 mmHg 60 40 RV PA 20 Atria a c v x y 0 Ventricles Phonocardiogram S4 R S1 A2 P2 S3 Ejection Opening click snap T P U Q S PR ST seg seg Electrocardiogram PR QRS interval interval QT interval FIGURE 7-1The cardiac cycle.
  3. 3. 156 Part II Diagnostic and Therapeutic Information TABLE 7-1BLOOD PRESSURE LEVELS FOR THE 50TH, 90TH, 95TH, AND 99TH PERCENTILES OFBLOOD PRESSURE FOR GIRLS AGE 1–17 YEARS BY PERCENTILES OF HEIGHT2 SBP, mmHg BP Percentile of Height*Age, y Percentile† 5th 10th 25th 50th 75th 90th 95th 1 50th 83 84 85 86 88 89 90 90th 97 97 98 100 101 102 103 95th 100 101 102 104 105 106 107 99th 108 108 109 111 112 113 114 2 50th 85 85 87 88 89 91 91 90th 98 99 100 101 103 104 105 95th 102 103 104 105 107 108 109 99th 109 110 111 112 114 115 116 3 50th 86 87 88 89 91 92 93 90th 100 100 102 103 104 106 106 95th 104 104 105 107 108 109 110 99th 111 111 113 114 115 116 117 4 50th 88 88 90 91 92 94 94 90th 101 102 103 104 106 107 108 95th 105 106 107 108 110 111 112 99th 112 113 114 115 117 118 119 5 50th 89 90 91 93 94 95 96 90th 103 103 105 106 107 109 109 95th 107 107 108 110 111 112 113 99th 114 114 116 117 118 120 120 6 50th 91 92 93 94 96 97 98 90th 104 105 106 108 109 110 111 95th 108 109 110 111 113 114 115 99th 115 116 117 119 120 121 122 7 50th 93 93 95 96 97 99 99 90th 106 107 108 109 111 112 113 95th 110 111 112 113 115 116 116 99th 117 118 119 120 122 123 124 8 50th 95 95 96 98 99 100 101 90th 108 109 110 111 113 114 114 95th 112 112 114 115 116 118 118 99th 119 120 121 122 123 125 125 9 50th 96 97 98 100 101 102 103 90th 110 110 112 113 114 116 116 95th 114 114 115 117 118 119 120 99th 121 121 123 124 125 127 127
  4. 4. Chapter 7 Cardiology 157 DBP, mmHg Percentile of Height*5th 10th 25th 50th 75th 90th 95th 38 39 39 40 41 41 42 52 53 53 54 55 55 56 56 57 57 58 59 59 60 64 64 65 65 66 67 67 43 44 44 45 46 46 47 57 58 58 59 60 61 61 61 62 62 63 64 65 65 69 69 70 70 71 72 72 47 48 48 49 50 50 51 7 61 62 62 63 64 64 65 65 66 66 67 68 68 69 73 73 74 74 75 76 76 50 50 51 52 52 53 54 64 64 65 66 67 67 68 68 68 69 70 71 71 72 76 76 76 77 78 79 79 52 53 53 54 55 55 56 66 67 67 68 69 69 70 70 71 71 72 73 73 74 78 78 79 79 80 81 81 54 54 55 56 56 57 58 68 68 69 70 70 71 72 72 72 73 74 74 75 76 80 80 80 81 82 83 83 55 56 56 57 58 58 59 69 70 70 71 72 72 73 73 74 74 75 76 76 77 81 81 82 82 83 84 84 57 57 57 58 59 60 60 71 71 71 72 73 74 74 75 75 75 76 77 78 78 82 82 83 83 84 85 86 58 58 58 59 60 61 61 72 72 72 73 74 75 75 76 76 76 77 78 79 79 83 83 84 84 85 86 87 Continued
  5. 5. 158 Part II Diagnostic and Therapeutic Information TABLE 7-1BLOOD PRESSURE LEVELS FOR THE 50TH, 90TH, 95TH, AND 99TH PERCENTILESOF BLOOD PRESSURE FOR GIRLS AGE 1–17 YEARS BY PERCENTILESOF HEIGHT2 (Continued) SBP, mmHg BP Percentile of Height*Age, y Percentile† 5th 10th 25th 50th 75th 90th 95th 10 50th 98 99 100 102 103 104 105 90th 112 112 114 115 116 118 118 95th 116 116 117 119 120 121 122 99th 123 123 125 126 127 129 129 11 50th 100 101 102 103 105 106 107 90th 114 114 116 117 118 119 120 95th 118 118 119 121 122 123 124 99th 125 125 126 128 129 130 131 12 50th 102 103 104 105 107 108 109 90th 116 116 117 119 120 121 122 95th 119 120 121 123 124 125 126 99th 127 127 128 130 131 132 133 13 50th 104 105 106 107 109 110 110 90th 117 118 119 121 122 123 124 95th 121 122 123 124 126 127 128 99th 128 129 130 132 133 134 135 14 50th 106 106 107 109 110 111 112 90th 119 120 121 122 124 125 125 95th 123 123 125 126 127 129 129 99th 130 131 132 133 135 136 136 15 50th 107 108 109 110 111 113 113 90th 120 121 122 123 125 126 127 95th 124 125 126 127 129 130 131 99th 131 132 133 134 136 137 138 16 50th 108 108 110 111 112 114 114 90th 121 122 123 124 126 127 128 95th 125 126 127 128 130 131 132 99th 132 133 134 135 137 138 139 17 50th 108 109 110 111 113 114 115 90th 122 122 123 125 126 127 128 95th 125 126 127 129 130 131 132 99th 133 133 134 136 137 138 139*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.
  6. 6. Chapter 7 Cardiology 159 DBP, mmHg Percentile of Height*5th 10th 25th 50th 75th 90th 95th 59 59 59 60 61 62 62 73 73 73 74 75 76 76 77 77 77 78 79 80 80 84 84 85 86 86 87 88 60 60 60 61 62 63 63 74 74 74 75 76 77 77 78 78 78 79 80 81 81 85 85 86 87 87 88 89 61 61 61 62 b3 64 64 7 75 75 75 76 77 78 78 79 79 79 80 81 82 82 86 86 87 88 88 89 90 62 62 62 63 64 65 65 76 76 76 77 78 79 79 80 80 80 81 82 83 83 87 87 88 89 89 90 91 63 63 63 64 65 66 66 77 77 77 78 79 80 80 81 81 81 82 83 84 84 88 88 89 90 90 91 92 64 64 64 65 66 67 67 78 78 78 79 80 81 81 82 82 82 83 84 85 85 89 89 90 91 91 92 93 64 64 65 66 66 67 68 78 78 79 80 81 81 82 82 82 83 84 85 85 86 90 90 90 91 92 93 93 64 65 65 66 67 67 68 78 79 79 80 81 81 82 82 83 83 84 85 85 86 90 90 91 91 92 93 93
  7. 7. 160 Part II Diagnostic and Therapeutic Information TABLE 7-2BLOOD PRESSURE LEVELS FOR THE 50TH, 90TH, 95TH, AND 99TH PERCENTILES OFBLOOD PRESSURE FOR BOYS AGE 1–17 YEARS BY PERCENTILES OF HEIGHT2 SBP, mmHg BP Percentile of Height*Age, y Percentile† 5th 10th 25th 50th 75th 90th 95th 1 50th 80 81 83 85 87 88 89 90th 94 95 97 99 100 102 103 95th 98 99 101 103 104 106 106 99th 105 106 108 110 112 113 114 2 50th 84 85 87 88 90 92 92 90th 97 99 100 102 104 105 106 95th 101 102 104 106 108 109 110 99th 109 110 111 113 115 117 117 3 50th 86 87 89 91 93 94 95 90th 100 101 103 105 107 108 109 95th 104 105 107 109 110 112 113 99th 111 112 114 116 118 119 120 4 50th 88 89 91 93 95 96 97 90th 102 103 105 107 109 110 111 95th 106 107 109 111 112 114 115 99th 113 114 116 118 120 121 122 5 50th 90 91 93 95 96 98 98 90th 104 105 106 108 110 111 112 95th 108 109 110 112 114 115 116 99th 115 116 118 120 121 123 123 6 50th 91 92 94 96 98 99 100 90th 105 166 108 110 111 113 113 95th 109 110 112 114 115 117 117 99th 116 117 119 121 123 124 125 7 50th 92 94 95 97 99 100 101 90th 106 107 109 111 113 114 115 95th 110 111 113 115 117 118 119 99th 117 118 120 122 124 125 126 8 50th 94 95 97 99 100 102 102 90th 107 109 110 112 114 115 116 95th 111 112 114 116 118 119 120 99th 119 120 122 123 125 127 127 9 50th 95 96 98 100 102 103 104 90th 109 110 112 114 115 117 118 95th 113 114 116 118 119 121 121 99th 120 121 123 125 127 128 129
  8. 8. Chapter 7 Cardiology 161 DBP, mmHg Percentile of Height*5th 10th 25th 50th 75th 90th 95th 34 35 36 37 38 39 39 49 50 51 52 53 53 54 54 54 55 56 57 58 58 61 62 63 64 65 66 66 39 40 41 42 43 44 44 54 55 56 57 58 58 59 59 59 60 61 62 63 63 66 67 68 69 70 71 71 44 44 45 46 47 48 48 7 59 59 60 61 62 63 63 63 63 64 65 66 67 67 71 71 72 73 74 75 75 47 48 49 50 51 51 52 62 63 64 65 66 66 67 66 67 68 69 70 71 71 74 75 76 77 78 78 79 50 51 52 53 54 55 55 65 66 67 68 69 69 70 69 70 71 72 73 74 74 77 78 79 80 81 81 82 53 53 54 55 56 57 57 68 68 69 70 71 72 72 72 72 73 74 75 76 76 80 80 81 82 83 84 84 55 55 56 57 58 59 59 70 70 71 72 73 74 74 74 74 75 76 77 78 78 82 82 83 84 85 86 86 56 57 58 59 60 60 61 71 72 72 73 74 75 76 75 76 77 78 79 79 80 83 84 85 86 87 87 88 57 58 59 60 61 61 62 72 73 74 75 76 76 77 76 77 78 79 80 81 81 84 85 86 87 88 88 89 Continued
  9. 9. 162 Part II Diagnostic and Therapeutic Information TABLE 7-2BLOOD PRESSURE LEVELS FOR THE 50TH, 90TH, 95TH, AND 99TH PERCENTILESOF BLOOD PRESSURE FOR BOYS AGE 1–17 YEARS BY PERCENTILESOF HEIGHT2 (Continued) SBP, mmHg BP Percentile of Height*Age, y Percentile† 5th 10th 25th 50th 75th 90th 95th 10 50th 97 98 100 102 103 105 106 90th 111 112 114 115 117 119 119 95th 115 116 117 119 121 122 123 99th 122 123 125 127 128 130 130 11 50th 99 100 102 104 105 107 107 90th 113 114 115 117 119 120 121 95th 117 118 119 121 123 124 125 99th 124 125 127 129 130 132 132 12 50th 101 102 104 106 108 109 110 90th 115 116 118 120 121 123 123 95th 119 120 122 123 125 127 127 99th 126 127 129 131 133 134 135 13 50th 104 105 106 108 110 111 112 90th 117 118 120 122 124 125 126 95th 121 122 124 126 128 129 130 99th 128 130 131 133 135 136 137 14 50th 106 107 109 111 113 114 115 90th 120 121 123 125 126 128 128 95th 124 125 127 128 130 132 132 99th 131 132 134 136 138 139 140 15 50th 109 110 112 113 115 117 117 90th 122 124 125 127 129 130 131 95th 126 127 129 131 133 134 135 99th 134 135 136 138 140 142 142 16 50th 111 112 114 116 118 119 120 90th 125 126 128 130 131 133 134 95th 129 130 132 134 135 137 137 99th 136 137 139 141 143 144 145 17 50th 114 115 116 118 120 121 122 90th 127 128 130 132 134 135 136 95th 131 232 134 136 138 139 140 99th 139 140 141 143 145 146 147*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.
  10. 10. Chapter 7 Cardiology 163 DBP, mmHg Percentile of Height*5th 10th 25th 50th 75th 90th 95th 58 59 60 61 61 62 63 73 73 74 75 76 77 78 77 78 79 80 81 81 82 85 86 86 88 88 89 90 59 59 60 61 62 63 63 74 74 75 76 77 78 78 78 78 79 80 81 82 82 86 86 87 88 89 90 90 59 60 61 62 63 63 64 7 74 75 75 76 77 78 79 78 79 80 81 82 82 83 86 87 88 89 90 90 91 60 60 61 62 63 64 64 75 75 76 77 78 79 79 79 79 80 81 82 83 83 87 87 88 89 90 91 91 60 61 62 63 64 65 65 75 76 77 78 79 79 80 80 80 81 82 83 84 84 87 88 89 90 91 92 92 61 62 63 64 65 66 66 76 77 78 79 80 80 81 81 81 82 83 84 85 85 88 89 90 91 92 93 93 63 63 64 65 66 67 67 78 78 79 80 81 82 82 82 83 83 84 85 86 87 90 90 91 92 93 94 94 65 66 66 67 68 69 70 80 80 81 82 83 84 84 84 85 86 87 87 88 89 92 93 93 94 95 96 97
  11. 11. 164 Part II Diagnostic and Therapeutic Information 115 95th 110 90th 105 100 75th Systolic BP 95 50th 90 85 80 75 70 65 0 1 2 3 4 5 6 7 8 9 10 11 12 Months 75 95th 70 90th Diastolic BP 65 75th 60 55 50th 50 45 0 1 2 3 4 5 6 7 8 9 10 11 12 90th Months Percentile Systolic BP 76 98 101 104 105 106 106 106 106 106 106 105 105 Diastolic BP 68 65 64 64 65 65 66 66 66 67 67 67 67 Height (cm) 54 55 56 58 61 63 66 68 70 72 74 75 77 Weight (kg) 4 4 4 5 5 6 7 8 9 9 10 10 11 FIGURE 7-2Age-specific percentiles of blood pressure (BP) measurements in boys from birth to12 months of age; Korotkoff phase IV (K4) used for diastolic BP. (From Task Forceon Blood Pressure Control in Children: Report of the Second Task Force on BloodPressure Control in Children. Pediatrics 1987;79[1]:1–25.)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 inspiration3. S3: Heard best at the apex or LLSB4. S4: Heard at the apexSee Box 7-1 for abnormal heart sounds.3C. Systolic and Diastolic Sounds1. Ejection click: Sounds like splitting of S1 but is most audible at the apex, in contrast to the normal finding of a split S1, which is best heard at the LLSB. May also be heard at the LUSB with valvular pulmonary stenosis (PS). Associated with stenosis of the semilunar
  12. 12. Chapter 7 Cardiology 165 115 110 95th 105 90th 100 75th Systolic BP 95 90 50th 85 80 75 70 65 0 1 2 3 4 5 6 7 8 9 1 01 1 1 2 Months 95th 70 7 90th 65 Diastolic BP 75th 60 50th 55 50 45 0 1 2 3 4 5 6 7 8 9 1 01 1 1 2 90th Months Percentile Systolic BP 87 101 106 106 106 105 105 105 105 105 105 105 105 Diastolic BP 68 65 63 63 63 65 66 67 68 68 69 69 69 Height (cm) 51 59 63 66 68 70 72 73 74 76 77 78 80 Weight (kg) 4 4 5 5 6 7 8 9 9 10 10 11 11 FIGURE 7-3Age-specific percentile of blood pressure (BP) measurements in girls from birth to12 months of age; Korotkoff phase IV (K4) used for diastolic BP. (From Task Forceon Blood Pressure Control in Children: Report of the Second Task Force on BloodPressure Control in Children. Pediatrics 1987;79[1]:1–25.) valves and large great arteries (e.g., systemic hypertension; pulmonary hypertension; idiopathic dilation of the pulmonary artery; tetralogy of Fallot [TOF], in which the aorta is dilated; and persistent truncus arteriosus)2. Midsystolic click with or without a late systolic murmur: Heard near the apex in mitral valve prolapse3. Diastolic opening snap: Audible at the apex or LLSB in mitral stenosis
  13. 13. 166 Part II Diagnostic and Therapeutic Information 110 Upper 95% CL 100 90 Systolic blood pressure 80 70 (mmHg) 60 50 Lower 95% CL 40 30 20 10 0 24 26 28 30 32 34 36 38 40 42 44 46 Postconceptional age (wk) FIGURE 7-4Linear regression of mean systolic blood pressure on postconceptional age(gestational age in weeks plus weeks after delivery). (Data from Zubrow AB, HulmanS, Kushner H, et al: Determinants of blood pressure in infants admitted to neonatalintensive care units: a prospective multicenter study. Philadelphia Neonatal BloodPressure Study Group. J Perinatol 1995;15:470–479.) BOX 7-1 SUMMARY OF ABNORMAL HEART SOUNDS • Widely Split S1: Ebstein’s 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), occasional normal child • Narrowly Split S2: Pulmonary hypertension, AS, delay in LV contraction (e.g., LBBB), occasional 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, occasional 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 complianceAS, Aortic stenosis; ASD, atrial septal defect; LBBB, left bundle-branch block; MR, mitralregurgitation; PAPVR, partial anomalous pulmonary venous return; PS, pulmonary stenosis; RBBB,right bundle-branch block; TGA, transposition of the great arteries; TOF, tetralogy of Fallot; TS,tricuspid stenosis.Modified from Park MK: Pediatric cardiology for practitioners, 5th ed. St. Louis, Mosby, 2008,p. 25.
  14. 14. Chapter 7 Cardiology 167D. Murmurs4 (http://www.murmurlab.org)1. Benign heart murmurs: Caused by a disturbance of the laminar flow of blood, frequently produced as the diameter of the blood’s pathway decreases and the velocity increasesa. Present in more than 80% of children sometime during childhood, most commonly beginning at age 3 to 4 yearsb. Accentuated in high-output states, especially with fever and anemiac. Normal electrocardiogram (ECG) and radiographic findingsNOTE: ECG and chest radiograph are not routinely useful or cost-effectivescreening tools for distinguishing benign from pathologic murmurs.d. Clinical characteristics summarized in Table 7-332. 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 7 pulses3. Systolic and diastolic heart murmurs (Box 7-2) TABLE 7-3COMMON INNOCENT HEART MURMURSType (Timing) Description of Murmur Age Group Classic vibratory murmur Maximal at LMSB or between LLSB and 3–6 yr; occasionally (Still’s murmur; systolic) apex in infancy Grade 2–3/6 in intensity Low-frequency vibratory, twanging string, groaning, squeaking, or musical Pulmonary ejection Maximal at LUSB 8–14 yr murmur (systolic) Early to midsystolic Grade 1–3/6 in intensity Blowing in quality Pulmonary flow murmur Maximal at LUSB Premature and of newborn (systolic) Transmits well to left and right chest, full-term newborns axilla, and back Usually disappears Grade 1–2/6 in intensity by 3–6 mo Venous hum (continuous) Maximal at right (or left) supraclavicular 3–6 yr 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 Carotid bruit (systolic) Right supraclavicular area over carotids Any age Grade 2–3/6 in intensity Occasional thrill over carotidLLSB, 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, p. 36.
  15. 15. 168 Part II Diagnostic and Therapeutic Information BOX 7-2 SYSTOLIC AND DIASTOLIC HEART MURMURS RUSB Aortic valve stenosis (supravalvar, subvalvar) Aortic regurgitation 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 LLSB Ventricular septal defect, including atrioventricular septal defect Vibratory innocent murmur (Still’s murmur) HOCM (IHSS) Tricuspid regurgitation Tetralogy of Fallot Tricuspid stenosis APEX Mitral regurgitation Vibratory innocent murmur (Still’s murmur) Mitral valve prolapse Aortic stenosis HOCM (IHSS) Mitral stenosisThe 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, p. 30. IV. LIPID MONITORING RECOMMENDATIONS (AMERICAN ACADEMY OF PEDIATRICS RECOMMENDATIONS)A. Screening of Children and Adolescents5Perform targeted screening of fasting lipid profile in children >2 years ofage who fulfill one of the following criteria:1. Parents or grandparents with premature cardiovascular disease (≤55 years of age for men and ≤65 years of age for women)2. Parent with elevated blood cholesterol level (≥240 mg/dL) or other pattern of dyslipidemia
  16. 16. Chapter 7 Cardiology 1693. Parental history is unobtainable; particularly for those with other risk factors such as smoking, obesity/overweight, or diabetes mellitus4. Patients with diseases that increase risk of premature cardiovascular disease (CVD): Diabetes, kidney disease, congenital/acquired heart disease, history of Kawasaki’s disease, childhood cancer survivorsB. Goals for Lipid Levels in Childhood1. Total cholesterola. Acceptable (<170 mg/dL): Repeat measurement in 3–5 yearsb. Borderline (170–199 mg/dL): Repeat cholesterol and average with previous measurement. If <170 repeat in 3–5 years. If ≥170, obtain lipoprotein analysisc. High (≥200 mg/dL): Obtain lipoprotein analysis2. Low-density lipoprotein (LDL) cholesterola. Acceptable (<110 mg/dL) 7b. Borderline (110–129 mg/dL)c. High (≥130 mg/dL)C. Management of Hyperlipidemia51. Normal and borderline elevated LDL levels: Education, risk factor intervention including diet, smoking cessation, and an exercise program. For borderline levels, reevaluate in 1 year2. High LDL levels: Examine for secondary causes (liver, thyroid, renal disorders) and familial disorders. Initiate low-fat, low-cholesterol diet; reevaluate in 3 months3. Drug therapy: Should be considered in children >8 years of age after failure of 6–12 month trial of diet therapy as follows:a. LDL >190 mg/dL without other cardiovascular disease risk factorsb. LDL >160 mg/dL with risk factors (diabetes, obesity, hypertension, positive family history of premature cardiovascular disease)c. LDL >130 mg/dL in children with diabetes mellitusd. Bile acid sequestrants and statins are the usual first-line drugs for treatment in children4. 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 V. ELECTROCARDIOGRAPHYA. Basic Electrocardiography Principles1. Lead placement (Fig. 7-5)2. ECG complexes (see Fig. 7-1)a. P wave: Represents atrial depolarizationb. QRS complex: Represents ventricular depolarizationc. T wave: Represents ventricular repolarizationd. U wave: May follow T wave, representing late phases of ventricular repolarization
  17. 17. 170 Part II Diagnostic and Therapeutic Information 90° aVR aVL 180° 0° I V6 A B V5 III II aVF V4R V4 90° V1 V2 V3 FIGURE 7-5A, Hexaxial reference system. B, Horizontal reference system. (Modified from ParkMK, Guntheroth WG: How to read pediatric ECGs, 4th ed. Philadelphia, Mosby,2006, p. 3.) TABLE 7-4NORMAL PEDIATRIC ELECTROCARDIOGRAM (ECG) PARAMETERS Heart PR QRS Rate QRS Interval DurationAge (bpm) Axis* (sec)* (sec)† 0–7 days 95–160 +30 to 0.08–0.12 0.05 (125) 180 (110) (0.10) (0.07) 1–3 wk 105–180 +30 to 0.08–0.12 0.05 (145) 180 (110) (0.10) (0.07) 1–6 mo 110–180 +10 to 0.08–0.13 0.05 (145) +125 (+70) (0.11) (0.07) 6–12 mo 110–170 +10 to 0.10–0.14 0.05 (135) +125 (+60) (0.12) (0.07) 1–3 yr 90–150 +10 to 0.10–0.14 0.06 (120) +125 (+60) (0.12) (0.07) 4–5 yr 65–135 0 to +110 0.11–0.15 0.07 (110) (+60) (0.13) (0.08) 6–8 yr 60–130 −15 to 0.12–0.16 0.07 (100) +110 (+60) (0.14) (0.08) 9–11 yr 60–110 −15 to 0.12–0.17 0.07 (85) +110 (+60) (0.14) (0.09) 12–16 yr 60–110 −15 to 0.12–0.17 0.07 (85) +110 (+60) (0.15) (0.10) >16 yr 60–100 −15 to 0.12–0.20 0.08 (80) +110 (+60) (0.15) (0.10)*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.
  18. 18. Chapter 7 Cardiology 1713. Systematic approach for evaluating ECGs (Table 7-4 shows normal ECG parameters)3,6: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: Heart rate (beats per minute) = 60 divided by the average R-R interval in seconds, or 1500 divided by the R-R interval in millimetersb. Rhythm (1) Sinus rhythm: Every QRS complex is preceded by a P wave, normal PR interval (although the PR interval may be prolonged, as in first-degree atrioventricular [AV] block), and normal P-wave axis (upright P in lead I and aVF) (2) There is normal respiratory variation of the R-R interval without 7 morphologic changes of the P wave or QRS complex Lead V1 Lead V6R Wave S Wave R Wave S WaveAmplitude Amplitude R/S Amplitude Amplitude R/S(mm)† (mm)† Ratio (mm)† (mm)† Ratio 13.3 (25.5) 7.7 (18.8) 2.5 4.8 (11.8) 3.2 (9.6) 2.2 10.6 (20.8) 4.2 (10.8) 2.9 7.6 (16.4) 3.4 (9.8) 3.3 9.7 (19) 5.4 (15) 2.3 12.4 (22) 2.8 (8.3) 5.6 9.4 (20.3) 6.4 (18.1) 1.6 12.6 (22.7) 2.1 (7.2) 7.6 8.5 (18) 9 (21) 1.2 14 (23.3) 1.7 (6) 10 7.6 (16) 11 (22.5) 0.8 15.6 (25) 1.4 (4.7) 11.2 6 (13) 12 (24.5) 0.6 16.3 (26) 1.1 (3.9) 13 5.4 (12.1) 11.9 (25.4) 0.5 16.3 (25.4) 1.0 (3.9) 14.3 4.1 (9.9) 10.8 (21.2) 0.5 14.3 (23) 0.8 (3.7) 14.7 3 (9) 10 (20) 0.3 10 (20) 0.8 (3.7) 12
  19. 19. 172 Part II Diagnostic and Therapeutic Information Lead I Lead aVF −90 0° – +90° ±180 0 +90 −90 0° – −90° ±180 0 +90 −90 +90° – ±180° ±180 0 +90 −90 −90° – ±180° ±180 0 +90 FIGURE 7-6Locating 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,p. 17.)c. Axis: 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)The R-R interval should extend from the R wave in the QRS complex in which you are measuring QT to the preceding R wave. Normal values for QTc are as follows: (1) 0.44 sec is 97th percentile for infants 3 to 4 days old7 (2) ≤0.45 sec in all males >1 week of age and prepubescent females (3) ≤0.46 sec for postpubescent femalese. 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: There is 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
  20. 20. Chapter 7 Cardiology 173g. Q waves: Normal Q waves are usually <0.04 sec in duration and <25% of the 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 ageh. ST-segment and T-wave evaluation: ST-segment elevation or depression >1 mm in limb leads and >2 mm in precordial leads is consistent with myocardial ischemia or injury. Tall, peaked T waves may be seen in hyperkalemia. Flat or low T waves may be seen in hypokalemia, hypothyroidism, normal newborn, and myocardial and pericardial ischemia and inflammation (Table 7-5 and Fig. 7-7)i. 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) 7 TABLE 7-5NORMAL T-WAVE AXISAge 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. J-Depression Abnormal ST-Segments R R R T P P T P T Q Q J Q S S S A B C FIGURE 7-7Nonpathologic (nonischemic) and pathologic (ischemic) ST and T changes.A, Characteristic nonischemic ST-segment alteration called J depression; note thatthe ST slope is upward. B and C, Ischemic or pathologic ST-segment alterations.B, Downward slope of the ST segment. C, Horizontal segment is sustained. (FromPark MK, Guntheroth WG: How to read pediatric ECGs, 4th ed. Philadelphia, Mosby;2006, p. 107.)
  21. 21. 174 Part II Diagnostic and Therapeutic Information RAE LAE CAE > 0.10 > 3mm > 0.10 V1 FIGURE 7-8Criteria for atrial enlargement. CAE, combined atrial enlargement; LAE, left atrialenlargement; RAE, right atrial enlargement. (From Park MK: Pediatric cardiology forpractitioners, 5th ed. St. Louis, Mosby, 2008, p. 53.) 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 ventricle strain (associated with inverted T wave in V1 with tall R wave) LEFT VENTRICULAR HYPERTROPHY (LVH) CRITERIA Left ventricle 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 ageB. ECG Abnormalities1. Nonventricular arrhythmias (Table 7-6; Figs. 7-9 and 7-10)82. Ventricular arrhythmias (Table 7-7; Fig. 7-11)3. Nonventricular conduction disturbances (Fig. 7-12 and Table 7-8)94. Ventricular conduction disturbances (Table 7-9) Text continued on page 180
  22. 22. TABLE 7-6NONVENTRICULAR ARRHYTHMIASName/Description Cause TreatmentSINUSTACHYCARDIA Normal sinus rhythm with HR >95th Hypovolemia, shock, anemia, Address underlying percentile for age (usually <230 sepsis, fever, anxiety, CHF, cause beats/min) PE, myocardial disease, drugs (e.g., β-agonists, albuterol, caffeine, atropine)BRADYCARDIA Normal sinus rhythm with HR <5th Normal (especially in athletic Address underlying percentile for age individuals), increased ICP, cause; if symptomatic, hypoxia, hyperkalemia, refer to inside back hypercalcemia, vagal cover for bradycardia stimulation, hypothyroidism, algorithm hypothermia, drugs (e.g., digoxin, β-blockers), long QT 7SUPRAVENTRICULAR*PREMATURE ATRIAL CONTRACTION (PAC) Narrow QRS complex; ectopic focus Digitalis toxicity, medications Treat digitalis toxicity; in atria with abnormal P wave (e.g., caffeine, theophylline, otherwise no treatment morphology sympathomimetics), normal needed variantATRIAL FLUTTER Atrial rate 250–350 beats/min; Dilated atria, previous Synchronized characteristic sawtooth or flutter intra-atrial surgery, valvular cardioversion or pattern with variable ventricular or ischemic heart disease, overdrive pacing; treat response rate and normal QRS idiopathic in newborns underlying cause complexATRIAL FIBRILLATION Irregular; atrial rate 350–600 Wolff-Parkinson-White Synchronized beats/min, yielding characteristic syndrome and those listed cardioversion; then fibrillatory pattern (no discrete P previously for atrial flutter may need waves) and irregular ventricular (except not idiopathic), anticoagulation response rate of about 110–150 alcohol exposure, familial pretreatment beats/min with normal QRS complexSVT Sudden run of three or more Most commonly idiopathic, but Vagal maneuvers, consecutive premature may be seen in congenital adenosine; if unstable, supraventricular beats at >230 heart disease (e.g., Ebstein’s need immediate beats/min, with narrow QRS anomaly, transposition) synchronized complex and abnormal P wave; cardioversion (0.5 j/kg either sustained (>30 sec) or up to 1 j/kg). Consult nonsustained cardiologist. See “Tachycardia with Poor Perfusion” or “Tachycardia with Adequate Perfusion” algorithms in back of handbook Continued
  23. 23. 176 Part II Diagnostic and Therapeutic Information TABLE 7-6NONVENTRICULAR ARRHYTHMIAS (Continued)Name/Description Cause Treatment 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; Cardiac surgery, idiopathic Adjust for clinical simultaneous depolarization of situation; consult atria and ventricles yields invisible cardiology P wave or retrograde P wave III. Ectopic atrial tachycardia: Rapid Idiopathic AV nodal blockade, firing of ectopic focus in atrium ablationNODAL ESCAPE/JUNCTIONAL RHYTHM Abnormal rhythm driven by AV node Common after surgery of atria Often requires no impulse, giving normal QRS treatment. If rate is complex and invisible P wave slow enough, may (buried in preceding QRS or T require pacemaker wave) or retrograde P wave (negative in lead II, positive in aVR), seen in sinus bradycardia*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 Figure 7-9, 7-10.7AV, Atrioventricular; CHF, congestive heart failure; HR, heart rate; ICP, intracranial pressure; PE, pulmonary embolism; SA, sinoatrial; SVT, supraventricular tachycardia. RR 2XRR p1 Premature atrial contraction (PAC) Atrial flutter Atrial fibrillation FIGURE 7-9Supraventricular arrhythmias. p1, Premature atrial contraction. (From Park MK,Guntheroth WG: How to read pediatric ECGs, 4th ed. Philadelphia, Mosby, 2006,p. 129.)
  24. 24. Chapter 7 Cardiology 177 7 ORT (WPW) FIGURE 7-10Supraventricular tachycardia pathway: Mechanism for orthodromic reentry(Wolff-Parkinson-White syndrome). Diagram shows the sinoatrial (SA) node (upperleft circle), with the atrioventricular (AV) node (above the horizontal line) and bundlebranches crossing to the ventricle (below the horizontal line). (Adapted from WalshEP: Cardiac arrhythmias. In Fyler DC [ed]: Nadas’ pediatric cardiology. Philadelphia,Hanley & Belfus, 1992, p. 384.) RR 2XRR Premature ventricular contraction (PVC) PVC p p p p p Ventricular tachycardia Ventricular fibrillation FIGURE 7-11Ventricular arrhythmias. P, P wave. (From Park MK, Guntheroth WG: How to readpediatric ECGs, 4th ed. Philadelphia, Mosby, 2006, p. 138.)
  25. 25. 178 Part II Diagnostic and Therapeutic Information TABLE 7-7VENTRICULAR ARRHYTHMIASName/Description Cause TreatmentPREMATURE VENTRICULAR CONTRACTION (PVC) Ectopic ventricular focus Myocarditis, myocardial None. More worrisome if causing early depolarization. injury, cardiomyopathy, associated with underlying Abnormally wide QRS complex long QT, congenital and heart disease or syncope, if appears prematurely, usually acquired heart disease, worse with activity, or if with full compensatory pause. drugs (catecholamines, they are multiform May be unifocal or multifocal. theophylline, caffeine, (especially couplets). Bigeminy: Alternating normal anesthetics), MVP, Address underlying cause, and abnormal QRS complexes; anxiety, hypokalemia, rule out structural heart Trigeminy: Two normal QRS hypoxia, hypomagnesemia disease complexes followed by an Can be normal variant abnormal one. Couplet: Two consecutive PVCsVENTRICULAR TACHYCARDIA Series of three or more PVCs at See causes of PVCs (70% See “Tachycardia with Poor rapid rate (120–250 beats/ have underlying cause) Perfusion” and min), with wide QRS complex “Tachycardia with Adequate and dissociated, retrograde, Perfusion” algorithms in or no P wave. back of handbookVENTRICULAR FIBRILLATION Depolarization of ventricles in Myocarditis, MI, Requires immediate uncoordinated, asynchronous postoperative state, defibrillation. See algorithm pattern, yielding abnormal digitalis or quinidine for “Asystole and Pulseless QRS complexes of varying size toxicity, catecholamines, Arrest” at back of book and morphology with severe hypoxia, electrolyte irregular, rapid rate. Rare in disturbances, long QT children.MI, Myocardial infarction; MVP, mitral valve prolapse. TABLE 7-8NONVENTRICULAR CONDUCTION DISTURBANCESName/Description* Cause TreatmentFIRST-DEGREE HEART BLOCK Abnormal but asymptomatic Acute rheumatic fever, tickborne No specific treatment delay in conduction through (i.e., Lyme) disease, connective except address the AV node, yielding prolongation tissue disease, congenital heart underlying cause of PR interval disease, cardiomyopathy, digitalis toxicity, postoperative state, normal childrenSECOND-DEGREE HEART BLOCK: MOBITZ TYPE I (WENCKEBACH) Progressive lengthening of PR Myocarditis, cardiomyopathy, Address underlying cause interval until a QRS complex congenital heart disease, is not conducted. Does not postoperative state, MI, toxicity usually progress to complete (digitalis, β-blocker), normal heart block children, Lyme disease, lupus
  26. 26. Chapter 7 Cardiology 179 TABLE 7-8NONVENTRICULAR CONDUCTION DISTURBANCES (Continued)Name/Description* Cause TreatmentSECOND-DEGREE HEART BLOCK: MOBITZ TYPE II Loss of conduction to ventricle Same as for Mobitz Type I Address underlying without lengthening of the PR cause; may need interval. May progress to pacemaker complete heart blockTHIRD-DEGREE (COMPLETE) HEART BLOCK Complete dissociation of atrial Congenital due to maternal If bradycardic and and ventricular conduction. P lupus or other connective tissue symptomatic, consider wave and PP interval regular; disease, structural heart pacing; see bradycardia RR interval regular and much disease; acquired (acute algorithm on inside slower. Width of QRS complex rheumatic fever, myocarditis, back cover will be narrow and faster with Lyme carditis, postoperative, underlying junctional cardiomyopathy, MI, drug 7 pacemaker, wide and slower overdose) with ventricular pacemaker*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.AV, Atrioventricular; MI, myocardial infarction. p p p p First-degree AV block Second-degree AV block Mobitz type I p p p p p p (Wenckebach phenomenon) p p p p p p Mobitz type II p p p p p p p p p 2:1 AV block R R R R Complete (third-degree) p p p p p p p p p p AV block FIGURE 7-12Conduction blocks. P, P wave; R, QRS complex. (From Park MK, Guntheroth WG:How to read pediatric ECGs, 4th ed. Philadelphia, Mosby, 2006, p. 141.)
  27. 27. 180 Part II Diagnostic and Therapeutic Information TABLE 7-9VENTRICULAR CONDUCTION DISTURBANCESName/Description Criteria Causes/TreatmentRIGHT BUNDLE-BRANCH BLOCK (RBBB) Delayed right bundle conduction 1. RAD ASD, surgery with right prolongs RV depolarization 2. Prolonged or wide QRS ventriculostomy, Ebstein’s time, leading to wide QRS with terminal slurred R′ anomaly, coarctation in (m-shaped RSR′ or RR′) infants <6 mo, endocardial in V1, V2, aVR cushion defect, and partial 3. Wide and slurred S anomalous pulmonary wave in leads I and V6 venous return; occasionally occurs in normal childrenLEFT BUNDLE-BRANCH BLOCK (LBBB) Delayed left bundle conduction 1. Wide negative QS Hypertension, ischemic or prolongs septal and LV complex in lead V1 with valvular heart disease, depolarization time, leading to loss of septal R wave cardiomyopathy wide QRS with loss of usual 2. Entirely positive wide R septal signal; there is still a or RR′ complex in lead predominance of left ventricle V6 with loss of septal Q forces. Rare in children waveWOLFF-PARKINSON-WHITE (WPW) Atrial impulse transmitted via 1. Shortened PR interval Acute management of SVT if anomalous conduction pathway 2. Delta wave necessary as previously to ventricles, bypassing AV 3. Wide QRS described; consider ablation node and normal ventricular of accessory pathway if conduction system. Leads to recurrent SVT. All patients premature and prolonged need cardiology referral depolarization of ventricles. Bypass pathway is a predisposing condition for SVT.ASD, Atrial septal defect; AV, atrioventricular; LV, left ventricle; RAD, right axis deviation; RV, right ventricle; SVT, supraventricular tachycardia.C. Myocardial Infarction (MI) in Children1. 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 children2. Frequent ECG findings in children with acute MI 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 hoursc. 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
  28. 28. Chapter 7 Cardiology 181 Hyperacute phase Elevated ST segment (a few hours) Deep and wide Q wave Deep and wide Q wave Early evolving phase Elevated ST segment (a few days) Diphasic T wave Late evolving phase Deep and wide Q wave (2–3 weeks) Sharply inverted T wave 7 Resolving phase Deep and wide Q wave (for years) Almost normal T wave FIGURE 7-13Sequential changes during myocardial infarction. (From Park MK, Guntheroth WG:How to read pediatric ECGs, 4th ed. Philadelphia, Mosby, 2006, p. 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 artery3. Other criteria:a. Elevated creatinine kinase (CK)/MB fraction: Not specific for acute MI in childrenb. Cardiac troponin I: More sensitive indicator of early myocardial damage in children.11 Becomes elevated within hours of cardiac injury, persists for 4 to 7 days, is specific for cardiac injuryD. ECG Findings Secondary to Electrolyte Disturbances, Medications, and Systemic Illnesses1. Digitalis:a. Digitalis effect: Associated with shortened QTc interval, ST depression (scooped or sagging), mildly prolonged PR interval, and flattened T wavesb. Digitalis toxicity: Primarily arrhythmias (bradycardia, supraventricular tachycardia, ectopic atrial tachycardia, ventricular tachycardia, atrioventricular [AV] block)2. Other conditions (Table 7-10)7,12E. Long QT1. Diagnosis: See Section V for normal QTc ranges. Elevated QTc in the absence of other underlying causes (electrolyte disturbances,
  29. 29. 182 Part II Diagnostic and Therapeutic Information TABLE 7-10SYSTEMIC EFFECTS ON ELECTROCARDIOGRAM Short Long Prolonged ST-T QT QT-U QRS ChangesCHEMISTRY Hyperkalemia X X Hypokalemia X X Hypercalcemia X Hypocalcemia X Hypermagnesemia Hypomagnesemia XDRUGS Digitalis X X Phenothiazines T Phenytoin X Propranolol X Tricyclics T T T VerapamilMISCELLANEOUS CNS injury X X Friedreich’s ataxia X Duchenne’s muscular dystrophy Myotonic dystrophy X X Collagen vascular disease X Hypothyroidism Hyperthyroidism X X Lyme disease X Holt-Oram, maternal lupusCNS, 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, p. 172, and Walsh EP: Cardiac arrhythmias. In Fyler DC, Nadas A (eds): Pediatric Cardiology. Philadelphia, Hanley & Belfus, 1992, pp 141–143. prematurity). The diagnosis may be supported by associated bradycardia, second-degree AV block, multiform premature ventricular contractions (PVCs), ventricular tachycardia, or abnormal T-wave morphologies. 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. Treadmill exercise test may prolong the QTc and will sometimes incite arrhythmias2. Complications: Associated with the ventricular arrhythmias (torsades de pointes), syncope, and sudden death3. Management:a. Congenital long QT: β-blockers and/or defibrillators; rarely require cardiac sympathetic denervation or cardiac pacemakers
  30. 30. Chapter 7 Cardiology 183Sinus Sinus AV VentricularTachycardia Bradycardia Block Tachycardia Miscellaneous X X Low-voltage Ps; peaked Ts X X X X X X T X T T 7 X X T T T X X X X X X Atrial flutter X X Atrial flutter X X X X X Low voltage X X X Xb. Acquired long QT: Treatment of arrhythmias, discontinue precipitating drug, correction of metabolic abnormalities VI. CONGENITAL HEART DISEASETable 7-11 shows common syndromes associated with cardiac lesions.A. Acyanotic Lesions (Table 7-12)B. Cyanotic Lesions (Table 7-13)An oxygen challenge test is used to evaluate the etiology of cyanosisin neonates. Obtain baseline arterial blood gas (ABG) with saturation atFiO2 = 0.21, then place infant in an oxygen hood at FiO2 = 1 for aminimum of 10 min, and repeat ABG. Pulse oximetry will not be usefulfor following the change in oxygenation once the saturations reach 100%(approximately PaO2 >90 mmHg).13–161. See Table EC 7-A on Expert Consult for interpretation of oxygen challenge test2. Table EC 7-B on Expert Consult shows acute management of hypercyanotic spells in TOF
  31. 31. 184 Part II Diagnostic and Therapeutic Information TABLE 7-11MAJOR SYNDROMES ASSOCIATED WITH CARDIAC DEFECTSSyndrome Dominant Cardiac Defect CHARGE TOF, truncus arteriosus, aortic arch abnormalities DiGeorge Aortic arch anomalies, TOF, truncus arteriosus, VSD, PDA Trisomy 21 Atrioventricular septal defects, VSD Marfan Aortic root dissection, mitral valve prolapse Loeys-Dietz Aortic root dissection with higher risk of rupture at smaller dimensions Noonan Supravalvular pulmonic stenosis, LVH Turner COA, bicuspid aortic valve 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 archASD, 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 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, p. 10–12.C. Surgeries and Other Interventions1. 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) (Fig. 7-14)3. Palliative superior vena cava-to-pulmonary artery shunts such as the Glenn shunt (superior vena cava [SVC] to the right pulmonary artery [RPA]) or Hemi-Fontan: Directs a portion of the systemic venous return directly into the pulmonary blood flow (usually performed outside of the neonatal period in infants with lower pulmonary vascular resistance) as an intermediate step to a Fontan procedure (see Fig. 7-14)4. Fontan procedure: Glenn shunt, together with 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)
  32. 32. Chapter 7 Cardiology 185 Bidirectional Blalock-Taussig Glenn shunt shunt Modified Blalock-Taussig shunt Waterston-Cooley Potts shunt shunt FIGURE 7-14 7Schematic diagram of cardiac shunts.5. Norwood procedure: Used for hypoplastic left heart syndromea. Stage 1 (neonatal period): Anastomosis of the proximal main pulmonary artery (MPA) to the aorta, with aortic arch reconstruction and transection and patch closure of the distal MPA; a modified right Blalock-Taussig shunt (subclavian artery to RPA) to provide pulmonary blood flow; alternatively, a right ventricle to pulmonary artery conduit can be used for pulmonary blood flow (Sano modification). An atrial septal defect is created to allow for adequate left to right flowb. Stage 2 (3–6 months of age): Bidirectional Glenn shunt or Hemi- Fontan to reduce volume overload of single right ventriclec. Modified Fontan (12–18 months of age)6. Repair of TGA:a. Atrial inversion (Mustard or Senning operation) (rarely performed today)b. Arterial switch7. Ross procedure: Pulmonary root autograft for aortic stenosis; autologous pulmonary valve replaces aortic valve, and aortic or pulmonary allograft replaces pulmonary valve VII. IMAGINGA. Chest radiograph1. Evaluate the heart:a. Size: Cardiac shadow should be less than 50% of thoracic width (the maximal width between the inner margins of the ribs, as measured on a posteroanterior radiograph during inspiration)b. Shape: Can aid in the diagnosis of chamber/vessel enlargement and some congenital heart disease (Fig. 7-15)c. Situs (levocardia, mesocardia, dextrocardia) Text continued on page 190
  33. 33. 186 Part II Diagnostic and Therapeutic Information TABLE 7-12ACYANOTIC CONGENITAL HEART DISEASELesion Type % of CHD/Examination Findings Ventricular septal 20%–25% of CHD defect (VSD) 2–5/6 holosystolic murmur, loudest at the LLSB, ± systolic thrill ± apical diastolic rumble with large shunt S2 may be narrow and P2 may be increased, with large VSD and pulmonary hypertension Atrial septal defect Wide, fixed split S2 with grade 2–3/6 SEM at the LUSB (ASD) May have mid-diastolic rumble at LLSB Patent ductus 5%–10% of CHD in term infants; 40–60% in VLBW infants arteriosus (PDA) 1–4/6 continuous “machinery” murmur loudest at the LUSB. Wide pulse pressure Atrioventricular septal 30%–60% occur in Down syndrome defects Hyperactive precordium with systolic thrill at the LLSB and loud S2 ± grade 3–4/6 holosystolic regurgitant murmur along the LLSB ± systolic murmur of MR at apex ± mid-diastolic rumble at LLSB or at apex ± Gallop rhythm Pulmonary stenosis Ejection click at LUSB with valvular PS—click intensity varies with (PS) 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 Aortic stenosis (AS) Systolic thrill at RUSB, suprasternal notch, or over carotids Ejection click, which does not vary with respiration, if valvular AS Harsh SEM (2–4/6) at second RICS or third LICS with radiation to the neck and apex ± early diastolic decrescendo murmur as a result of AR Narrow pulse pressure if severe stenosis Coarctation of the 8%–10% of CHD with male/female ratio of 2 : 1. aorta 2–3/6 SEM at the LUSB radiating to the left interscapular area May present as Bicuspid valve is often associated and thus may have systolic ejection (1) Infant in CHF click at the apex and RUSB (2) Child with HTN BP in lower extremities will be lower than in upper extremities (3) Child with Pulse oximetry discrepancy of >5% between upper and lower murmur extremities is also suggestive of coarctation
  34. 34. Chapter 7 Cardiology 187ECG Findings Chest Radiograph Findings Small VSD: Normal May show cardiomegaly and increased PVMs dependent Medium VSD: LVH ± LAE on the amount of left to right shunting Large VSD: BVH ± LAE, pure RVH Small ASD: Normal May show cardiomegaly with increased PVMs if Large ASD: RAD and mild RVH or RBBB hemodynamically significant ASD with RSR′ in V1 Small–moderate PDA: Normal or LVH May have cardiomegaly and increased PVMs, depending Large PDA: BVH on size of shunt (see Chapter 18 for treatment) Superior QRS axis Cardiomegaly with increased PVMs RVH and LVH may be present 7 Mild PS: Normal Normal heart size with normal to decreased PVMs Moderate PS: RAD and RVH Severe PS: RAE and RVH with strain Mild AS: Normal Usually normal Moderate–severe AS: LVH ± strain In infancy: RVH or RBBB Marked cardiomegaly and pulmonary venous congestion. In older children: LVH Rib notching from collateral circulation usually not seen in children younger than 5 years because collaterals not yet establishedAR, Aortic regurgitation; 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; RICS, right intercostal space; RBBB, right bundle-branch block; RUSB, right upper sternal border; RVH, right ventricular hypertrophy; SEM, systolic ejection murmur. VLBW, very low birth weight i.e. <1500 g.
  35. 35. 188 Part II Diagnostic and Therapeutic Information TABLE 7-13CYANOTIC CONGENITAL HEART DISEASE Examination Chest RadiographLesion Findings ECG Findings Findings Tetralogy of Fallot: Loud SEM at LMSB and RAD and RVH Boot-shaped heart 1. Large VSD LUSB and a loud, with normal heart 2. RVOT obstruction single S2 ± thrill at size ± decreased 3. RVH the LMSB and LLSB. PVMs 4. Overriding aorta Tet spells: Occur in Degree of RVOT young infants. As obstruction will RVOT obstruction determine whether increases or systemic there is clinical resistance decreases, cyanosis. If there is right to left shunting only mild PS, there across the VSD will be a left to right occurs. May present shunt, and the child with tachypnea, will be acyanotic. increasing cyanosis, Increased obstruction and decreasing leads to increased murmur. See Table EC right to left shunting 7-B for treatment across the VSD and cyanosis Transposition of great Nonspecific. Extreme RAD and RVH (due Classic finding: arteries cyanosis. Loud, single to RV acting as “egg on a string” S2. No murmur unless systemic with cardiomegaly; there is associated ventricle). possible increased VSD or PS Upright T wave PVMs in V1 after age 3 days may be only abnormality. Tricuspid atresia: Single S2 + grade Superior QRS axis; Normal or slightly Absent tricuspid 2–3/6 systolic RAE or CAE, and enlarged heart valve and regurgitation murmur LVH size; may have hypoplastic RV and at the LLSB if VSD is boot-shaped heart PA. Must have ASD, present. Occasional PDA, or VSD to PDA murmur survive
  36. 36. Chapter 7 Cardiology 189 TABLE 7-13CYANOTIC CONGENITAL HEART DISEASE (Continued) Examination Chest RadiographLesion Findings ECG Findings Findings Total anomalous Hyperactive RV RAD, RVH (RSR′ in Cardiomegaly and pulmonary venous impulse, quadruple V1). May see RAE increased PVMs; return rhythm, S2 fixed and classic finding is Instead of draining widely split, 2–3/6 “snowman in a into LA, pulmonary SEM at LUSB, and snowstorm,” but veins drain into the mid-diastolic rumble this is rarely seen following locations. at LLSB until after age 4 Must have ASD or months PFO for survival 1. Supracardiac (most common): SVC 7 2. Cardiac: coronary sinus or RA 3. Subdiaphragmatic: IVC, portal vein, ductus venosus, or hepatic vein 4. Mixed typeOTHER Cyanotic CHDs that occur at a frequency of <1% each include pulmonary atresia, Ebstein’s 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.

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