Hypertrophic cardiomyopathy

Question 1

Pathophysiology?

Answer 1

UNEXPLAINED left ventricle hypertrophy with asymmetric septal involvement -> diastolic dysfunction (impaired filling) -> reduced systolic output volume -> reduced peripheral and myocardial perfusion and sudden death

Question 2

Etiology and epidemiology?

Answer 2

Autosomal dominant involving sarcomere protein genes (myosin heavy chain) most common cause of sudden death in young athletes and most common hereditary heart disease (family hx of sudden death)

Question 3

What diseases mimic HCM?

Answer 3

Chronic HTN, aortic stenosis, amyloidosis

Question 4

Clinical features and exacerbating factors?

Answer 4

Asymptomatic if non obstructive
-angina, dyspnea, syncope
-worsen with physical activity, dehydration, drugs (ACEI, ARB, diuretics)
Ejection systolic murmur (due to LVOB) worse with valsalva and standing, better with sitting and handgrip
Holosystolic murmur due to functional mitral regurgitation
S4 added sound
Jerky pulse (pulse biseferiens) : LVOB causes sudden increase in pulse then slower longer rise so biphasic pulse

Question 5

Diagnosis?

Answer 5

Echo: septum is 1.5 times thicker than the posterior wall

ECG and X-ray
Genetic analysis

Question 6

Treatment?

Answer 6

Consider implantable cardioverter defibrillator to prevent sudden cardiac death:
-absolute indications: hx of prev ventricular tachycardia/fibrillation or arrest
Relative indication: hx of 1st degree family SCD, ventricle wall thickness >30mm, syncope of unknown cause

Symptomatic patients: BB or CCB
if refractory to medical tx: septal reduction therapy