Download Hypertrophic Cardiomyopathy Lange-pp. 362

Hypertrophic Cardiomyopathy
Lange-pp. 362-364
http://www.mayoclinic.com/health/hypertrophic-cardiomyopathy/DS00948
http://www.4hcm.org/WCMS/index.php
Essentials of Diagnosis
 May present with dyspnea, chest pain, syncope.
 Though LV outflow gradient is classic, symptoms are primarily related
to diastolic dysfunction
 Echocardiogram shows septal hypertrophy, which is usually
asymmetric, and enhanced contractility. Systolic anterior motion of the
anterior mitral valve is present if there is outflow tract obstruction.
 The highest risk group for sudden death includes those with a marked
LVH, with a family history for sudden death, with ventricular ectopy,
and with an abnormal BP response to exercise.
Genetic disease with prevalence of 1 in 500 in the general adult population.
Caused by mutations in any of 10 genes coding for proteins of the cardiac
sarcomere. Genetic screening is currently limited to screening known or
suspected familial groups
Hallmark abnormality of HCM is:
1. Inappropriate and marked left ventricular hypertrophy, ranging from mild
to extreme, esp. localized hypertrophy, typically in the anterior septum. This
hypertrophy may result in areas of ischemia or infarction due to abnormal
microvasculature, impaired coronary vasodilator reserve, or mismatch
between myocardial mass and coronary circulation. This causes scarring.
2. Outflow tract obstruction, not demonstrated in the majority; causes a
loud systolic murmur and may be symptomatic with exertion intolerance,
syncope, or sudden death
Used to be called HOCM (hypertrophic obstructive cardiomyopathy) or IHSS
(idiopathic hypertrophic subaortic stenosis)
Male predominance slightly up to mid life; female predominance is found in
patients older thatn 60
Presenting signs and symptoms:
Majority of patients are asymptomatic or have mild symptoms
Dyspnea, angina, presyncope or syncope with symptoms worse with
exertion.
Atrial fibrillation occurs in ¼ of patients thus hemodynamic compromise
because of inadequate filling of the hypertrophied ventricle.
Physical examination:
Forceful and enlarged precordial impulse, often laterally displaced
Murmur results from flow through the left ventricular outflow tract, and is
usually a harsh crescendo-decrescendo, starts well after the first heart
sound and is best heard between the apex and left sterna border. The
murmur increases with maneuvers that increase the gradient through
increased contractility, decreased preload, or decreased afterload;
conversely, the murmur decreases with interventions that decrease
contractility, increase preload or increase afterload.
Squatting (increased afterload) = decreased murmur
Standing (decreased afterload) = increased murmur
Valsalva (decreased preload) = increased murmur
Precordial impulse-presystolic, systolic, and late systolic impulse (“triple
ripple”)
Syncope, history of cardiac arrest, documented sustained ventricular
tachyarrhythmias and family history of sudden death are predictors of
sudden death.
The ECHO is essential and helps to examine outflow tract obstruction
EKG-left ventricular hypertrophy and prominent Q waves in the inferior and
lateral leads due to septal hypertrophy. Giant negative T waves suggest the
apical variant of HCM
Stress testing
Beta blockers are considered the initial therapy of choice; AICD if considered
high risk for sudden death