Can left ventricular hypertrophy (LVH) cause a murmur?

Can Left Ventricular Hypertrophy Cause a Murmur?

Left ventricular hypertrophy (LVH) itself does not directly cause a murmur, but it is commonly associated with conditions that do produce murmurs, particularly when LVH results from left ventricular outflow tract obstruction or valvular disease.

Understanding the Relationship Between LVH and Murmurs

LVH represents increased left ventricular mass due to enlarged cardiomyocytes, which develops as a compensatory response to pressure or volume overload, or as a primary pathological process 1, 2. The key distinction is that the murmur originates from the underlying cardiac pathology causing the LVH, not from the hypertrophy itself 3.

Clinical Scenarios Where LVH and Murmurs Coexist

Hypertrophic Cardiomyopathy (HCM)

• HCM with obstruction produces a characteristic systolic ejection murmur that is loudest at the 4th left intercostal space and increases with Valsalva maneuver (unlike most other murmurs which decrease) 3.
• The murmur results from left ventricular outflow tract obstruction caused by systolic anterior motion of the mitral valve and mid-systolic septal contact, not from the hypertrophy per se 3.
• A fourth heart sound (S4) is common in obstructive HCM, and the carotid pulse is characteristically brisk and jerky with systolic rebound 3.

Aortic Stenosis with Secondary LVH

• Valvular aortic stenosis produces a midsystolic crescendo-decrescendo murmur at the second right intercostal space that radiates to the carotids 3.
• LVH develops secondary to chronic pressure overload from the stenotic valve 3, 2.
• The murmur originates from turbulent flow across the narrowed aortic valve, while LVH is a consequence of the increased afterload 3.
• ECG may reveal QRS voltage criteria for LVH, left atrial abnormality, and ST-T wave changes 3.

Hypertensive Heart Disease

• Many asymptomatic older patients with systemic hypertension have grade 1-2 midsystolic murmurs related to sclerotic aortic valve leaflets or flow into tortuous, noncompliant great vessels 3.
• These patients often have LVH from chronic hypertension, but the murmur is due to aortic valve sclerosis or altered vascular compliance, not the LVH itself 3.
• The absence of LVH on ECG may be reassuring, but echocardiography is frequently necessary to distinguish aortic sclerosis from true stenosis 3.

Subaortic Obstruction

• Discrete subaortic stenosis produces a systolic ejection murmur at the left sternal border and apex without radiation to the carotids and without an ejection click 3.
• LVH develops from the chronic outflow obstruction, and marked LVH attributable to obstruction is an indication for surgical intervention 3.

Important Clinical Distinctions

What LVH Does NOT Cause

• LVH alone, in the absence of outflow obstruction or valvular disease, does not generate a murmur 3.
• Patients with LVH from hypertension without valvular abnormalities or outflow obstruction typically have no murmur on examination.

Associated Findings That Help Differentiate Causes

The ACC/AHA guidelines provide specific differentiating features for left ventricular outflow tract obstruction 3:

• Pulse pressure after ventricular premature beat: Increases in valvular, supravalvular, and discrete subvalvular stenosis but decreases in obstructive HCM 3.
• Valsalva effect on systolic murmur: Decreases in most forms of stenosis but increases in obstructive HCM 3.
• Fourth heart sound: Common in severe valvular stenosis and obstructive HCM, but uncommon in supravalvular or discrete subvalvular stenosis 3.

Diagnostic Approach

Physical Examination Findings

• Assess for murmur characteristics: timing (systolic vs. diastolic), location, radiation, response to maneuvers 3.
• Evaluate carotid pulse: parvus et tardus suggests valvular stenosis, while brisk and jerky suggests HCM 3.
• Listen for additional sounds: ejection clicks suggest valvular stenosis (unless heavily calcified), S4 suggests severe stenosis or HCM 3.

When to Pursue Further Workup

• Symptoms of syncope, angina, or heart failure with a midsystolic murmur warrant echocardiography to rule out significant aortic stenosis 3.
• Asymptomatic patients with grade 2/6 or louder midsystolic murmurs should undergo echocardiography to distinguish benign flow murmurs from pathological stenosis 3.
• ECG showing LVH voltage criteria in the presence of a murmur increases suspicion for hemodynamically significant valvular disease 3.

Common Pitfalls to Avoid

• Do not attribute a murmur to LVH alone—always search for the underlying structural or hemodynamic cause 3.
• Do not rely solely on peak Doppler gradient to assess aortic stenosis severity; use mean gradient and aortic valve area indexed to body surface area 3.
• Do not dismiss soft murmurs in elderly hypertensive patients—they may represent early aortic stenosis requiring surveillance 3.
• Do not confuse the click-murmur of mitral valve prolapse with findings of HCM—dynamic auscultation helps differentiate these conditions 3.

Clinical Significance

LVH is an independent risk factor for cardiovascular events, heart failure, arrhythmias, and mortality 4, 5. When LVH is associated with a murmur, the combination suggests significant underlying structural heart disease requiring comprehensive evaluation 3. The presence of LVH on ECG or echocardiography in a patient with a cardiac murmur should prompt aggressive diagnostic workup to identify treatable causes such as aortic stenosis or HCM 3, 2.