Hypertrophic Cardiomyopathy

Rough crescendo-decrescendo murmur, heard best at left lower sternal border

+/-S4 caused by left atrial contraction into stiffened left ventricle

+/- holosystolic MR

Valsalva maneuver and rapid standing from squatting position increase murmur

Why? Both maneuvers decrease venous return, which decreases LV volume. As a result, the septum and mitral valve come closer to each other, causing turbulent flow via increased narrowing of outflow tract.

Conversely, passive leg elevation (to 45 degrees) or rapid squatting from standing position decreases murmur by increasing venous return and LV volume

Right-Sided Murmurs

Pulmonic stenosis and tricuspid regurgitation are augmented with inspiration and decreased with expiration.

Why? Inspiration decreases intrathoracic pressure. This augments venous return and increased flow increases the murmurs.

Conversely, expiration decreases venous return and decreases the murmurs

Mitral Regurgitation (MR)

Holosystolic high-pitched “blowing” murmur, loudest at apex, radiates to axilla

Isometric handgrip and transient arterial occlusion increase murmur

Why? Isometric handgrip increases systemic vascular resistance, and transient arterial occlusion (BP cuff around both upper arms) increases afterload. This increases LV pressure results, causing augmented MR

Ventricular Septal Defect (VSD)

Harsh, holosystolic murmur heard best at left sternal border

+/- Apical mid-diastolic rumble due to increased flow across mitral valve

+/- Systolic thrill palpable over region of the murmur

Maneuvers to intensify VSD are the same as for MR: Isometric handgrip and transient arterial occlusion, via increased LV pressure and turbulent flow through VSD

Aortic Stenosis

Crescendo-decrescendo ejection murmur following ejection click, radiates to carotids

No maneuvers point to aortic stenosis, so when using maneuvers, it is a diagnosis of exclusion.

Sources:

Lembo, Nicholas J. et al. Bedside Diagnosis of Systolic Murmurs. NEJM 1988; 318:1572-8.

Lilly, Leonard S. Pathophysiology of Heart Disease, 3^rd ed. 8:185-208, 247, 359

Category: Cardiology Notes