Medscape is available in 5 Language Editions – Choose your Edition here.


Pediatric Hypertrophic Cardiomyopathy Clinical Presentation

  • Author: Christina Y Miyake, MD; Chief Editor: P Syamasundar Rao, MD  more...
Updated: Jan 04, 2016


Patients with hypertrophic cardiomyopathy (HCM) may be asymptomatic. Symptoms can include sudden cardiac death, dyspnea, syncope, presyncope, angina, palpitations, orthopnea, paroxysmal nocturnal dyspnea, congestive heart failure, and dizziness.

Sudden cardiac death

Sudden cardiac death is the most devastating presenting manifestation and, unfortunately, may be the first clinical manifestation of the disease, even among asymptomatic patients. It has the highest incidence in preadolescent and adolescent children and is typically associated with sports or vigorous exertion.

In more than 80% of individuals with HCM, the arrhythmia that causes sudden death is ventricular fibrillation. Many patients with HCM develop ventricular fibrillation after atrial fibrillation, atrial flutter, supraventricular tachycardia associated with Wolff-Parkinson-White syndrome, ventricular tachycardia, or low-cardiac-output hemodynamic collapse.

Early diagnosis is of prime importance if death is to be prevented by prescription of an appropriate level of safe activity, medications, surgery, or an implantable cardioverter defibrillator.[8] Because this is an autosomal dominantly inherited disease, screening of first-degree relatives with physical examination, electrocardiography (ECG), and echocardiography is useful to identify additional family members with HCM before the onset of significant symptoms or sudden death.


Dyspnea is the most common presenting symptom, occurring in as many as 90% of symptomatic patients. It is largely a consequence of elevated left ventricular diastolic filling pressures and transmission of those elevated pressures back into the pulmonary circulation. The elevated left ventricular filling pressures principally result from impaired diastolic compliance as a result of marked hypertrophy of the ventricle.


Syncope is a common symptom of HCM, resulting from inadequate cardiac output on exertion or from cardiac arrhythmia (either tachycardia or bradycardia). Syncope is more common in children and young adults with small left ventricular chamber size and evidence of ventricular tachycardia on ambulatory monitoring. Some patients have abnormalities in sinus node function, leading to sick sinus syndrome. Syncope identifies children with HCM who are at significantly increased risk of sudden death and warrants an urgent evaluation and aggressive treatment.


Presyncope refers to “graying out” spells that occur in the erect posture and can be relieved by the individual immediately lying down. These symptoms are exacerbated by vagal stimulation. Presyncope may also occur with nonsustained atrial or ventricular tachyarrhythmias.

Presyncope occurs commonly in patients with HCM and identifies a subgroup of patients who may be at increased risk for sudden death. Like syncope, presyncope warrants a directed evaluation to rule out malignant arrhythmias. However, dizziness and presyncope are common symptoms in teenagers and may simply represent vasodepressor reaction or a common faint. A thorough investigation is warranted to rule out potential malignant etiology of presyncopal symptoms.


Typical symptoms of angina are seen in children with HCM and occur in the absence of detectable coronary atherosclerosis. Impaired diastolic relaxation and markedly increased myocardial oxygen consumption due to ventricular hypertrophy result in subendocardial ischemia, particularly during exertion.


Palpitations are common in HCM. They are usually due to arrhythmia, such as premature atrial and ventricular beats, sinus pauses, intermittent atrioventricular (AV) block, atrial fibrillation, atrial flutter, supraventricular tachycardia, or ventricular tachycardia. Nonsustained ventricular tachycardia is another marker for a higher risk of sudden death.

Orthopnea and paroxysmal nocturnal dyspnea

Although orthopnea and paroxysmal nocturnal dyspnea are uncommon in children, these early signs of congestive heart failure are observed in individuals with severe cases of HCM. They occur when impaired diastolic function and elevated left ventricular filling pressure result in pulmonary venous congestion.

Congestive heart failure

Although relatively uncommon in children, congestive heart failure is present in 10% of children at initial presentation, most commonly in infants younger than 1 year. It is observed in individuals with severe cases of HCM. Congestive heart failure may occur as a result of a combination of impaired diastolic function and subendocardial ischemia. Systolic function in children with HCM is almost always well preserved, at least until the late stages of the disease.

Patients with congestive heart failure have a high likelihood of recurrent heart failure, as a consequence of both mitral regurgitation and profound diastolic dysfunction.


Dizziness is common in children with HCM who have elevated pressure gradients across the left ventricular outflow tract. Worsened by exertion, dizziness may be exacerbated by hypovolemia after high levels of exertion or increased insensible fluid loss (eg, during or after exposure to extreme heat).

Dizziness may be caused by medications or maneuvers (eg, rapid standing or a Valsalva maneuver during defecation) that decrease preload and afterload and increase the pressure gradient across the left ventricular outflow tract.

Dizziness also may be caused by arrhythmia-related hypotension and decreased cerebral perfusion. Nonsustained arrhythmias often cause symptoms of dizziness and presyncope, whereas sustained arrhythmias more likely lead to syncope, collapse, and sudden cardiac death.


Physical Examination

Most children with HCM do not have outflow tract obstruction and, therefore, may have completely normal physical examination findings. Abnormalities related to heart sounds, cardiac impulses, or murmurs may, however, be noted.

Heart sounds

The first heart sound (S1) is normal in patients with HCM. The second heart sound (S2) is usually split; however, in some patients with HCM and extreme outflow gradients, S2 is split paradoxically. A third heart sound (S3) or gallop is common in children with HCM but does not have the same ominous significance as in patients with valvular aortic stenosis or in adults. A fourth heart sound (S4) is frequently heard and is due to atrial systole against a highly noncompliant left ventricle.

Cardiac impulse

The apical precordial impulse is frequently displaced laterally and is usually abnormally forceful and enlarged. A double apical impulse, resulting from a forceful left atrial contraction against a highly noncompliant left ventricle, occurs commonly in children with HCM. A triple apical impulse, resulting from a late systolic bulge that occurs when the heart is almost empty and is performing near-isometric contraction, is highly characteristic but is less frequent than a double apical impulse.


The outflow murmur typically heard is a systolic ejection, crescendo-decrescendo murmur that is heard best between the apex and left sternal border; it radiates to the suprasternal notch but not to the carotid arteries or neck. The murmur directly varies with the subaortic gradient across the left ventricular outflow tract.

Because obstruction is dynamic and directly related to volume status, left ventricular outflow tract obstruction and murmur diminish with any increase in preload (eg, that elicited by a Valsalva maneuver, a Mueller maneuver, or squatting) or increase in afterload (eg, that elicited by a handgrip). The murmur and the gradient increase with any decrease in preload (eg, that elicited by nitrate medications, diuretics, or standing) or with any decrease in afterload (eg, that elicited by vasodilators).

A holosystolic murmur of mitral regurgitation is heard at the apex and left axilla in patients with systolic anterior motion of the mitral valve and significant left ventricular outflow gradients.

A diastolic decrescendo murmur of aortic regurgitation is heard in 10% of children with HCM, although mild aortic regurgitation can be detected by Doppler echocardiography in 33% of patients with the disorder.

Other findings

The jugular venous pulse reveals a prominent ‘a’ wave due to diminished right ventricular compliance secondary to massive hypertrophy of the ventricular septum.

A double carotid arterial pulse may occur. The carotid pulse rises quickly because of increased velocity of blood through the left ventricular outflow tract into the aorta. The carotid pulse then declines in mid-systole as the gradient develops, followed by a secondary rise in carotid pulsation during systole.



Complications of HCM may include the following:

  • Congestive heart failure
  • Arrhythmia
  • Infective mitral endocarditis
  • Atrial fibrillation with mural thrombosis formation
  • Sudden death
Contributor Information and Disclosures

Christina Y Miyake, MD Assistant Professor of Pediatric Cardiology, Texas Children's Hospital

Christina Y Miyake, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Cardiology, American Heart Association, Massachusetts Medical Society, Pediatric and Congenital Electrophysiology Society

Disclosure: Nothing to disclose.


Charles I Berul, MD Professor of Pediatrics and Integrative Systems Biology, George Washington University School of Medicine; Chief, Division of Cardiology, Children's National Medical Center

Charles I Berul, MD is a member of the following medical societies: American Academy of Pediatrics, Heart Rhythm Society, Cardiac Electrophysiology Society, Pediatric and Congenital Electrophysiology Society, American College of Cardiology, American Heart Association, Society for Pediatric Research

Disclosure: Received grant/research funds from Medtronic for consulting.

Chief Editor

P Syamasundar Rao, MD Professor of Pediatrics and Medicine, Division of Cardiology, Emeritus Chief of Pediatric Cardiology, University of Texas Medical School at Houston and Children's Memorial Hermann Hospital

P Syamasundar Rao, MD is a member of the following medical societies: American Academy of Pediatrics, American Pediatric Society, American College of Cardiology, American Heart Association, Society for Cardiovascular Angiography and Interventions, Society for Pediatric Research

Disclosure: Nothing to disclose.


Christopher Johnsrude, MD, MS Chief, Division of Pediatric Cardiology, University of Louisville School of Medicine; Director, Congenital Heart Center, Kosair Children's Hospital

Christopher Johnsrude, MD, MS is a member of the following medical societies: American Academy of Pediatrics and American College of Cardiology

Disclosure: St Jude Medical Honoraria Speaking and teaching

Ameeta Martin, MD Clinical Associate Professor, Department of Pediatric Cardiology, University of Nebraska College of Medicine

Ameeta Martin, MD is a member of the following medical societies: American College of Cardiology

Disclosure: Nothing to disclose.

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

  1. Lipshultz SE, Orav EJ, Wilkinson JD, Towbin JA, Messere JE, Lowe AM, et al. Risk stratification at diagnosis for children with hypertrophic cardiomyopathy: an analysis of data from the Pediatric Cardiomyopathy Registry. Lancet. 2013 Sep 2. [Medline].

  2. El-Saiedi SA, Seliem ZS, Esmail RI. Hypertrophic cardiomyopathy: prognostic factors and survival analysis in 128 Egyptian patients. Cardiol Young. 2013 Jul 29. 1-7. [Medline].

  3. Semsarian C, Ahmad I, Giewat M, Georgakopoulos D, Schmitt JP, McConnell BK, et al. The L-type calcium channel inhibitor diltiazem prevents cardiomyopathy in a mouse model. J Clin Invest. 2002 Apr. 109(8):1013-20. [Medline]. [Full Text].

  4. Jarcho JA, McKenna W, Pare JA, Solomon SD, Holcombe RF, Dickie S, et al. Mapping a gene for familial hypertrophic cardiomyopathy to chromosome 14q1. N Engl J Med. 1989 Nov 16. 321(20):1372-8. [Medline].

  5. Wilkinson JD, Lowe AM, Salbert BA, Sleeper LA, Colan SD, Cox GF, et al. Outcomes in children with Noonan syndrome and hypertrophic cardiomyopathy: a study from the Pediatric Cardiomyopathy Registry. Am Heart J. 2012 Sep. 164(3):442-8. [Medline].

  6. Colan SD, Lipshultz SE, Lowe AM, Sleeper LA, Messere J, Cox GF, et al. Epidemiology and cause-specific outcome of hypertrophic cardiomyopathy in children: findings from the Pediatric Cardiomyopathy Registry. Circulation. 2007 Feb 13. 115(6):773-81. [Medline].

  7. Ziolkowska L, Turska-Kmiec A, Petryka J, Kawalec W. Predictors of Long-Term Outcome in Children with Hypertrophic Cardiomyopathy. Pediatr Cardiol. 2015 Nov 2. [Medline].

  8. Maron BJ, Spirito P, Ackerman MJ, Casey SA, Semsarian C, Estes NA 3rd, et al. Prevention of sudden cardiac death with implantable cardioverter-defibrillators in children and adolescents with hypertrophic cardiomyopathy. J Am Coll Cardiol. 2013 Apr 9. 61(14):1527-35. [Medline].

  9. Bolin E, Lam W. A review of sensitivity, specificity, and likelihood ratios: evaluating the utility of the electrocardiogram as a screening tool in hypertrophic cardiomyopathy. Congenit Heart Dis. 2013 Sep. 8(5):406-10. [Medline].

  10. Jay A, Chikarmane R, Poulik J, Misra VK. Infantile hypertrophic cardiomyopathy associated with a novel MYL3 mutation. Cardiology. 2013. 124(4):248-51. [Medline].

  11. Cortez D, Sharma N, Cavanaugh J, et al. The spatial QRS-T angle outperforms the Italian and Seattle ECG-based criteria for detection of hypertrophic cardiomyopathy in pediatric patients. J Electrocardiol. 2015 Sep-Oct. 48 (5):826-33. [Medline].

  12. Epstein AE, DiMarco JP, Ellenbogen KA, Estes NA 3rd, Freedman RA, Gettes LS, et al. ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices) developed in collaboration with the American Association for Thoracic Surgery and Society of Thoracic Surgeons. J Am Coll Cardiol. 2008 May 27. 51(21):e1-62. [Medline].

  13. Almquist AK, Montgomery JV, Haas TS, Maron BJ. Cardioverter-defibrillator implantation in high-risk patients with hypertrophic cardiomyopathy. Heart Rhythm. 2005 Aug. 2(8):814-9. [Medline].

  14. Berul CI, Van Hare GF, Kertesz NJ, Dubin AM, Cecchin F, Collins KK, et al. Results of a multicenter retrospective implantable cardioverter-defibrillator registry of pediatric and congenital heart disease patients. J Am Coll Cardiol. 2008 Apr 29. 51(17):1685-91. [Medline].

  15. Kaski JP, Tome Esteban MT, Lowe M, et al. Outcomes after implantable cardioverter-defibrillator treatment in children with hypertrophic cardiomyopathy. Heart. 2007. 93(3):372-374. [Full Text].

  16. Maron BJ, Spirito P, Shen WK, Haas TS, Formisano F, Link MS, et al. Implantable cardioverter-defibrillators and prevention of sudden cardiac death in hypertrophic cardiomyopathy. JAMA. 2007 Jul 25. 298(4):405-12. [Medline].

  17. Sorajja P, Valeti U, Nishimura RA, Ommen SR, Rihal CS, Gersh BJ, et al. Outcome of alcohol septal ablation for obstructive hypertrophic cardiomyopathy. Circulation. 2008 Jul 8. 118(2):131-9. [Medline].

Hypertrophic cardiomyopathy. Image courtesy of Michael E. Zevitz, MD
Sarcomeric genes involved in hypertrophic cardiomyopathy (adapted from Priori 1999).
ECG of a 16-year-old with hypertrophic cardiomyopathy (HCM), demonstrating left ventricular hypertrophy pattern and "pseudo-preexcitation."
All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.