CARDIOLOGY UPDATE
From the 62nd Annual Brennemann Memorial Lectures, presented by the Los Angeles Pediatric Society
William A. Lutin, MD, PhD, Section of Pediatric Cardiology, Medical College of Georgia, Augusta
| HEART MURMURS IN CHILDREN: INNOCENT OR GUILTY?
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| Incidence: 50% of children have heart murmurs, but only 1% of children have heart disease; understanding clinical physiology
helps distinguish innocent from pathologic murmurs
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| Flow and tone: when blood flows through straight tube (ie, unrestricted vessels), red blood cells (RBCs) move at similar
velocities; small range in velocity corresponds with small range in frequency of sound, resulting in murmurs with “musical”
or “vibratory” quality; obstructions within tube introduce differences in pressure, leading to large range in velocity
of RBCs and frequencies of sound (murmurs sound harsh); low-frequency components detected as thrill in chest;
cardiac output—high ventricular pressure in patient with ventricular septal defect (VSD) results in consistent murmur
(ie, does not significantly change with increased cardiac output); if patient has audible murmur when lying supine but
not detectable when standing (ie, when cardiac output decreases), murmur innocent (no additional tests necessary)
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| Location and radiation: general principles—sound loudest over structure responsible for noise; sound radiates well
parallel to flow but not perpendicular to flow; clinical applications—in patient with VSD, murmur loudest over lower
left sternal border and may radiate toward right side; murmur not audible in back or carotids (perpendicular to flow)
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| History: prenatal history and risk factors may increase index of suspicion; early growth and development, especially
gross motor milestones (but not fine motor, cognitive, or social milestones), typically affected in children with heart
disease; age and clinical setting (eg, after infection with Streptococcus) when murmur first noted may increase index of
suspicion; level of activity and tolerance to exercise give clues to clinical relevance; clinical symptoms that increase
concern—respiratory symptoms (especially wheezing and recurrent respiratory illnesses); orthopnea, dyspnea, diaphoresis,
and cyanosis greatly increase index of suspicion; palpitations, chest pain, and syncope less helpful in diagnosis;
family history—presence of first-degree relatives with heart disease or history of sudden death increases concern
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| Noncardiac physical examination: overall appearance (eg, dysmorphia, physical development, physical indications of
syndromes) very important; vital signs should include respiratory rate and pattern, heart rate, and blood pressure (BP);
body proportions (body appears small relative to head in children with heart disease); pulses and BP—simultaneous
radial and femoral measurements recommended for all children; children with elevated systolic BP but normal diastolic
BP in right arm should have pulse and BP measured in 4 extremities; other points—check for thrill in suprasternal
notch; examine neck veins (flat or elevated); palpate for hepatomegaly and other characteristics of liver; check for cyanosis
and clubbing of fingers
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| Cardiovascular examination: inspection—look for precordial prominence and point of maximal impulse (PMI);
palpation—left and right ventricular impulses; thrills (check suprasternal notch, lower left sternal border, and apex);
precordial hyperactivity indicates problem (palpate precordium in all patients); heart sounds—use of stethoscope often
more accurate than other diagnostic techniques; splitting of second heart sound (S2 ) important (fixed splitting indicates
problem)
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| Describing heart murmurs: timing and duration; character; intensity; location of maximal loudness; radiation; physiologic
behavior (eg, maneuvers); grade—scored 1 to 6 (mild to severe); murmurs with thrill have score ≥4; timing—
ejection murmurs have pause between first heart sound (S1 ) and onset of murmur (when pressure in left ventricle overcomes
aortic pressure); holosystolic or decrescendo systolic murmurs begin with S1 (blood moves before semilunar
valves open, ie, pathologic); note—continuous murmur associated with cervical venous hum (not pathologic) distinguished
by gently compressing jugular vein (murmur stops)
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| Findings in patients with innocent heart murmurs: normal findings during adventitial examination, including growth
and vital signs; normal precordial activity and heart sounds (loudest at left upper sternal border, split physiologically,
and have normal amplitude)
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| Types of innocent murmurs: Still’s murmur—loudest at lower left sternal border; decreases when patient stands up;
pulmonary outflow murmur—nonspecific murmur, loudest at left upper sternal border; cervical venous hum—
continuous murmur (see above); carotid bruit—soft nonspecific systolic ejection murmur, loudest in supraclavicular
area (may propagate onto chest), but disappears when patient raises arms; peripheral pulmonary stenosis—in newborns
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| Characteristics of innocent murmurs: ejection type, with short duration and early peak; vibratory or musical quality;
maximum loudness usually occurs at lower left sternal border or left upper sternal border; radiation occurs along left
sternal border, not to back; murmur disappears when patient stands; no clicks or ectopic sounds; no murmur during
diastole
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 | Factors that increase intensity of innocent murmurs: fever; anemia; hyperthyroidism; exercise; agitation; medications that
increase cardiac output; pain
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| Other hints for diagnosis: serial examinations useful to assess variation in murmur (murmur that comes and goes likely
innocent); presence of cardiac symptoms increases index of suspicion; extra caution required when examining young
infants; echocardiography does not replace good physical examination and, in some cases, may lead to incorrect diagnosis
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| CAN WE PREVENT SUDDEN CARDIAC DEATH IN CHILDREN?
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| Background: identifying children at risk for sudden cardiac death (SCD) difficult; diagnostic tests associated with relatively
high morbidity and expense; Pediatric Clinics of North America: Sudden Cardiac Death in Children and Adolescents
(edited by Berger) good reference; incidence of sudden death in children—estimates range from 0.3 to 4.6
per 100,000 children; SCD accounts for 30% to 70% of sudden deaths in children
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| Sudden cardiac death: any natural death caused by acute circulatory failure that occurs minutes to 24 hr after onset of
symptoms in children >1 yr of age (termed sudden infant death syndrome [SIDS] in younger children); nonfatal
events—nonfatal episode of acute hemodynamic collapse termed acute life-threatening event (ALTE); pulse present
during syncope; SCD in children—poor survival after cardiopulmonary resuscitation (CPR); 50% of children at risk
have prodromal cardiac symptoms; diagnosis of cardiac problem often occurs after death; incidence—1 in 200,000
athletes (5 million high school athletes in United States); 75% to 80% of incidents occur at rest or with mild activity;
many patients have no warning symptoms; >50% of patients have no previous risk factors; many have no abnormal
findings on physical examination
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| Cardiac anomalies and SCD: hypertrophic cardiomyopathy (HCM)—60% of SCDs associated with exercise; 29% of
patients have history of syncope; coronary anomalies—66% of SCDs occur with exercise; only 7% of patients have
history of cardiac symptoms (chest pain most common); aortic stenosis—83% of SCDs associated with exercise; 20%
of patients have history of syncope
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| SCD in athletes: study found 85% of 158 athletes who died suddenly had cardiovascular etiology; 90% of SCDs occurred
in boys (69% associated with football or basketball); 36% of victims had hypertrophic disease, and 13% had coronary
anomalies; 85% of patients had medical evaluation before participating in sport (all cleared to play); cardiac
disease suspected in 3% of patients who had physical examinations; etiologic problem diagnosed before death in only 1
athlete
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| Postmortem diagnosis: myocarditis most common diagnosis, followed by hypertrophic disease; other diagnoses include
coronary anomalies, Wolff-Parkinson-White syndrome, stenosis of aortic valve, arrhythmia, Kawasaki syndrome, and
death following surgery for congenital heart disease (CHD)
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| Risk factors: undiagnosed structural CHD (eg, aortic stenosis, Ebstein’s anomaly of tricuspid valve, transposition of
great arteries, myocardial tumors, severe cyanosis); hypertrophic cardiomyopathy (most common cause of SCD in adolescents
and may account for 50% of exercise-related deaths); dilated cardiomyopathy or myocarditis (postmortem diagnosis
of myocarditis sometimes given when etiology unclear); congenital coronary anomalies (generally diagnosed
postmortem); acquired coronary disease; pulmonary hypertension and Marfan syndrome more commonly diagnosed
before death
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| Arrhythmias: electrocardiography (ECG) recommended for any patient (especially athletes) with history of syncope or
family history of sudden death; arrhythmias that increase risk include long QT syndrome, atrioventricular (AV) block,
and preexcitation syndromes (eg, Wolff-Parkinson-White)
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| Heart disease: previously diagnosed heart disease in children who suffer SCD include left ventricular outflow tract
(LVOT) obstruction, aortic valvular stenosis, hypertrophic disease, Eisenmenger syndrome, pulmonary hypertension,
severe pulmonary stenosis, or pulmonary atresias associated with coronary insufficiency; symptoms that increase
concern—chest pain, palpitations, syncope, presyncope, and dizziness, especially if associated with exertion, startling,
or emotional upset
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| Preparticipation evaluations for athletes: history—degree of tolerance to exercise; symptoms (eg, wheezing)
brought on with exercise; chest pain; syncope requires work-up, including ECG and probably echocardiography; eating
disorders; high-risk behaviors; near syncope; irregular heartbeat, palpitations, or dizziness at rest or during exercise;
musculoskeletal problems (helpful for identifying patients with Marfan syndrome); heart murmur; cardiac surgery;
family history—first-degree relative with SCD before 55 yr of age, hypertrophic disease, aortic aneurysm or dissection,
deafness (may help identify patients with long QT syndrome), CHD, cardiomyopathy, or arrhythmia; physical
examination—BP important (high BP associated with SCD; must control before participating in sports); Marfanoid
features; 4 extremity pulses (check for coarctation and pulsus bisferiens); careful cardiac examination, looking for underlying
CHD (eg, aortic valvular stenosis; follow-up required for patients with positive findings); auscultation in supine
(or squatting) and standing positions (and during Valsalva maneuver in patients with increased risk); laboratory
tests—no tests necessary if no red flags raised by family history or examination; ECG useful for patients with history
of syncope, near-syncope, palpitations, or family history of SCD (note QT interval, underlying cardiac rhythm, and AV
conduction; look for evidence of myocardial ischemia and myocarditis); patients with strong family history of HCM or
SCD need referral to cardiologist and echocardiography
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| Marfan syndrome: family history of aortic rupture and tall first-degree relatives increase index of suspicion; autosomal
dominant disorder; patients usually >95th percentile for height, have short upper body segment, long arms, hyperextensible
joints, lenticular dislocation, scoliosis, pectus excavatum, and slumped posture; cardiac findings include redundant
mitral valve (sometimes associated with late systolic click) and dilated descending aorta (sometimes resulting in
aortic insufficiency and early decrescendo diastolic murmur); no single diagnostic test; diagnosis often in doubt for
long period; cardiology follow-up—abnormalities in mitral valve indicate prophylaxis for subacute bacterial endocarditis
(SBE); excessive growth of aortic root may require treatment with β-blockers or replacement
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| HCM or hypertrophic obstructive cardiomyopathy (HOCM): dynamic obstruction in LVOT; obstruction—when
ventricular volume decreases (eg, afterload reduction following exercise), intraventricular septum squeezes LVOT (result
of abnormal pattern of myocytes within septum); symptoms—often none before SCD; dyspnea (especially with
exercise), fatigue, chest pain, syncope, palpitations, and (rarely) congestive heart failure (CHF) may occur, but syncope
only predictor of SCD; diagnosis—pulsus bisferiens; S4 sometimes present (S1 and S2 typically normal); 40% of patients
have murmur (heard only when standing or during Valsalva maneuver in some patients); murmur loudest at lower
left sternal border (sometimes radiates to carotids); echocardiography required for diagnosis (shows thick septum and
narrowed LVOT); treatment—restricted exercise (no competitive sports); β-blockers and calcium-channel blockers
(in patients <1 yr of age); diuretics, digoxin, and inotropic agents contraindicated (increase obstruction); procedures include
myomectomy, pacing maneuvers (right ventricle), implantation of defibrillator (reduces morbidity and mortality),
and ethanol ablation of septum (benefit uncertain); prognosis—50% of infants <1 yr of age die within first year;
1% to 4% annual mortality rate in older children; 5% progress to CHF when left ventricle “burns out”
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| Wolff-Parkinson-White syndrome: symptoms include fatigue with exercise, episodic dizziness, and tachycardia; ECG
shows delta waves and short PR interval; patients have supraventricular tachycardia (SVT) and increased risk for atrial
fibrillation and flutter, which may conduct rapidly to ventricle and cause sudden death
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| Long QT syndrome: length of QT interval normally <50% that of R-R interval; patients with long QT interval require
referral to cardiologist for medical management; torsades de point—disorganized ventricular tachycardia with characteristic
ECG; medications—many associated with prolongation of QT interval or torsades de point (see www.torsades.org)
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| Preventable deaths in adolescents: other causes of preventable deaths much more common in adolescents; reducing
mortality rates associated with substance abuse, suicide, accidents, anorexia, AIDS, pregnancy, and violence has important
role in primary care
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Educational Objectives
| The goal of this activity is to provide the clinician with information about heart murmurs and heart disease in children.
After hearing and assimilating this program, the clinician will be better able to:
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| 1. Discuss differences in physiology and presentation between innocent and pathologic heart murmurs.
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| 2. Identify the various types of innocent heart murmurs.
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| 3. Recognize red flags associated with heart disease in children.
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| 4. Discuss causes of sudden cardiac death (SCD) in children.
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| 5. Perform preparticipation physical examinations for athletes, and identify those patients in need of referral for further
cardiac evaluation.
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Discussed on This Program
Penicillin G [Bicillin C-R, Bicillin C-R 900/300, Bicillin L-A, Permapen, Pfizerpen, Wycillin]
Suggested Reading
Berger S, et al: Sudden death in children and adolescents. Pediatr Clin North Am 51:1653, 2004; Biancaniello T: Innocent
murmurs. Circulation 111:e20, 2005; Fitzgerald PT, Ackerman MJ: Drug-induced torsades de points: the evolving
role of pharmacogenetics. Heart Rhythm 2(2Suppl):S30, 2005; Gospe S, Camfield P: Cardiac causes of sudden
death: virtual panel discussion of posed questions. Semin Pediatr Neurol 12:67, 2005; Hulkower S, et al: Clinical inquiries:
do preparticipation clinical exams reduce morbidity and mortality for athletes? J Fam Pract 54:628, 2005;
Keren R, et al: Evaluation of a novel method for grading heart murmur intensity. Arch Pediatr Adolesc Med 159:329,
2005; Maron BJ, et al: Recommendations for physical activity and recreational sports participation for young patients
with genetic cardiovascular diseases. Circulation 109:2807, 2004; Maron BJ, et al: Task Force 1: Preparticipation
screening and diagnosis of cardiovascular disease in athletes. J Am Coll Cardiol 45:1322, 2005; Nugent AW, et al:
Clinical features and outcomes of childhood hypertrophic cardiomyopathy: results from a national population-based
study. Circulation 112:1332, 2005; O’Connor FG, et al: A pilot study of clinical agreement in cardiovascular preparticipation
examinations: how good is the standard of care? Clin J Sport Med 15:177, 2005; Ostman-Smith I, et al:
Echocardiographic and electrocardiographic identification of those children with hypertrophic cardiomyopathy who
should be considered at high-risk of dying suddenly. Cardiol Young 15:632, 2005; Pelech AN: The physiology of cardiac
auscultation. Pediatr Clin North Am 51:1515, 2004; Sarubbi B, et al: Electrophysiological evaluation of asymptomatic
ventricular pre-excitation in children and adolescents. Int J Cardiol 98:207, 2005; Strieper MJ: Distinguishing
benign syncope from life-threatening cardiac causes of syncope. Semin Pediatr Neurol 12:32, 2005; Vincent GM: The
Long QT and Brugada syndromes: causes of unexpected syncope and sudden cardiac death in children and young adults.
Semin Pediatr Neurol 12:15, 2005.
Faculty Disclosure
In adherence to ACCME guidelines, the Audio-Digest Foundation requests all lecturers to disclose any significant financial
relationship with the manufacturer or provider of any commercial product or service discussed. For this issue, the faculty reported
nothing to disclose.
Dr. Lutin was recorded in San Diego at the 62nd Annual Brennemann Memorial Lectures, sponsored by the Los Angeles
Pediatric Society, and held September 22-25, 2005. The Audio-Digest Foundation thanks Dr. Lutin and the Los
Angeles Pediatric Society for their cooperation in the production of this program.
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