Hypertrophic Cardiomyopathy

Reviewed and revised 1 September 2014

OVERVIEW

aetiology unknown (>50% autosomal dominant condition)
hypertrophied septum can cause dynamic left ventricular outflow tract obstruction (LVOTO) during systole
also can get dynamic anterior motion of the mitral valve leaflet towards septum (SAM – systolic anterior motion) -> causing further obstruction
this causes a pressure overload of LV and diastolic dysfunction

ASSESSMENT

History

Examination

double or even triple apical impulse
evidence of heart failure
jerky pulse
S2 may be paradoxically split if very high LVOT gradient
prominent a wave on JVP due to decreased RV compliance
Systolic ejection murmur (due to LVOTO)
- typically is a systolic ejection crescendo-decrescendo murmur
- best heard between the apex and left sternal border and radiates to the suprasternal notch but not to the carotid arteries or neck
- dynamic maneuvres: quieter with increase in preload (eg, squatting) or increase in afterload (eg, handgrip), louder 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 (mitral regurgitation due to systolic anterior motion of the mitral valve and significant LV outflow gradients)
Diastolic decrescendo murmur (aortic reurgitation) heard in 10% of patients,

Investigations

ECG:
-> LVH critieria
-> deep anterior lateral TWI
-> dagger-like Q waves in infero-lateral leads
ECHO:
-> asymmetric septal hypertrophy
-> systolic anterior movement of the mitral valve
-> early aortic valve closure

MANAGEMENT