Hypertrophic Cardiomyopathy Clinical Presentation

Updated: Apr 29, 2022
  • Author: Sandy N Shah, DO, MBA, FACC, FACP, FACOI; Chief Editor: Gyanendra K Sharma, MD, FACC, FASE  more...
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Symptoms of hypertrophic cardiomyopathy (HCM) can include dyspnea, syncope and presyncope, angina, palpitations, orthopnea, paroxysmal nocturnal dyspnea, congestive heart failure, dizziness, and sudden cardiac death.

Sudden cardiac death

Sudden cardiac death is the most devastating presenting manifestation of HCM. It has the highest incidence in preadolescent and adolescent children and is particularly related to extreme exertion. The risk of sudden death in children is as high as 6% per year.

In more than 80% of cases, the arrhythmia that causes sudden death is ventricular fibrillation. Many of these cases degenerate into ventricular fibrillation from rapid atrial arrhythmias, such as fibrillation, supraventricular tachycardia, or Wolff-Parkinson-White syndrome, while others result from ventricular tachycardia and low cardiac output hemodynamic collapse.


This is the most common presenting symptom, occurring in as many as 90% of symptomatic patients. Dyspnea largely is a consequence of elevated LV diastolic filling pressures (and transmission of those elevated pressures back into the pulmonary circulation). The elevated LV filling pressures principally are caused by impaired diastolic compliance as a result of marked hypertrophy of the ventricle.


Syncope is a very common symptom, resulting from inadequate cardiac output upon exertion or from cardiac arrhythmia. It occurs more commonly in children and young adults with small LV chamber size and evidence of ventricular tachycardia upon ambulatory monitoring.

Alternatively, syncope may be caused by arrhythmias, either tachycardias or bradycardias. Some patients with HCM have abnormalities in sinus node function, leading to sick sinus syndrome with alternating tachyarrhythmias and bradyarrhythmias or severe bradyarrhythmias.

Syncope and presyncope identify patients at high risk of sudden death and warrant an urgent workup and aggressive treatment.


Presyncope includes "graying-out" spells that occur in the erect posture and can be relieved by immediately lying down. They occur quite commonly and identify patients at high risk for sudden death. These symptoms are exacerbated by vagal stimulation. Presyncope also may occur with nonsustained atrial or ventricular tachyarrhythmias.


Typical symptoms of angina are quite common in patients with HCM and may occur in the absence of detectable coronary atherosclerosis. Impaired diastolic relaxation and markedly increased myocardial oxygen consumption are caused by ventricular hypertrophy that results in subendocardial ischemia, particularly during exertion.


Palpitations are common. These result from arrhythmias, such as premature atrial and ventricular beats, sinus pauses, atrial fibrillation, atrial flutter, supraventricular tachycardia, and ventricular tachycardia.

Orthopnea and paroxysmal nocturnal dyspnea

These are early signs of congestive heart failure and, while relatively uncommon, are observed in patients with severe HCM. They result from impaired diastolic function and elevated LV filling pressure. Orthopnea and paroxysmal nocturnal dyspnea result from pulmonary venous congestion.

Congestive heart failure

This is relatively uncommon but is observed in patients with severe HCM. It may occur as a result of a combination of impaired diastolic function and subendocardial ischemia. Systolic function in these patients almost always is well preserved.


Dizziness is common in patients with HCM with elevated pressure gradients across the LV outflow tract. It is worsened by exertion and may be exacerbated by hypovolemia following high levels of exertion or increased insensible fluid loss (eg, during extreme heat).

Dizziness also may occur as a result of maneuvers, such as rapid standing or Valsalva during defecation, or certain medications, such as diuretics, nitroglycerin, and vasodilating antihypertensive agents, that decrease preload and afterload and increase the pressure gradient across the LV outflow tract.

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


Physical Examination

Double apical impulse results from a forceful left atrial contraction against a highly noncompliant left ventricle. This occurs quite commonly in adults. Triple apical impulse results from a late systolic bulge that occurs when the heart is almost empty and is performing near-isometric contraction. This is a highly characteristic finding of hypertrophic cardiomyopathy (HCM); however, it occurs less frequently than does the double apical impulse.

First heart sound is normal. Second heart sound usually is normally split, but in some patients with severe outflow gradients, it is paradoxically split.

An S3 gallop is common in children, but it does not have the same ominous significance as in patients with valvular aortic stenosis. When it occurs in adults, it signifies decompensated congestive heart failure. A fourth heart sound, an S4, frequently is heard and results from atrial systole against a highly noncompliant left ventricle.

Jugular venous pulse reveals a prominent a wave caused by diminished right ventricular compliance secondary to massive hypertrophy of the ventricular septum.

Double carotid arterial pulse is common. The carotid pulse rises quickly because of the increased velocity of blood through the LV outflow tract and into the aorta. The carotid pulse then declines in midsystole as the gradient develops. This is followed by a secondary rise in carotid pulsation during late systole.

Apical precordial impulse frequently is displaced laterally and usually is abnormally forceful and enlarged.

Systolic ejection murmur typically is a systolic ejection crescendo-decrescendo murmur, which is best heard between the apex and left sternal border and radiates to the suprasternal notch but not to the carotid arteries or neck. The murmur and the gradient across the LV outflow tract diminish with any increase in preload (eg, Mueller maneuver, squatting) or increase in afterload (eg, handgrip). The murmur and the gradient increase with any decrease in preload (eg, Valsalva maneuver, nitrate administration, diuretic administration, standing) or with any decrease in afterload (eg, vasodilator administration).

Holosystolic murmur at the apex and axilla of mitral regurgitation is heard in patients with systolic anterior motion of the mitral valve and significant LV outflow gradients. Diastolic decrescendo murmur of aortic regurgitation is heard in 10% of patients, although mild aortic regurgitation can be detected by Doppler echocardiography in 33% of patients.