Monday, January 18, 2010

January 14th - MHH - HOCM/IHSS

Background: Hypertrophic Cardiomyopathy is inherited about half the time (autosomal dominant). It is these patients with inherited disease that have a high risk of ventricular arrythmias and sudden cardiac death. Annual Mortality in Adults is around 2%

Pathophysiology:  Patients can get asymmetrical septal hypertrophy, concentric hypertropy, and other areas of the heart may be involved. Due to this hypertrophy, a narrow outflow tract occurs and there is a pressure gradient that occurs. 


Patients can present along the spectrum of disease - syncope, dizziness/presyncope, signs of diastolic dysfunction (dyspnea, PND, orthopnea), myocardial ischemia (angina), palpitations (arrythmias), and sudden cardiac death.  However, most are asymptomatic early in the disease course, and remember that sudden cardiac death can be the first clinical feature.  The Exam will reveal a mid-systolic murmur in the RUSB that increases with Valsalva. An S4 is usually present.  Not uncommonly a double (and sometimes triple) apical impule is felt. Carotid pulse will be brisk, and is sometimes bifid. 

EKG and CXR:

Some may have deep T-wave inversions in the inferior and anterior leads of the EKG, some patients may have inferio-lateral Q-waves.  Both the EKG and CXR can reveal LVH and LAE.

Echocardiogram is diagnostic.  There are multiple findings, but a septum that is too thick (and thicker than the posterior wall) is usually present.  Outflow tract obstruction is usually seen, as well as abnormal motion of the anterior mitral leaflet.   Most patients should have a Holter Placed. Cardiac cath is not usually done on these patients unless surgical intervention is planned. 

Beta Blockers are the treatment of choice. These are given to those with a family history of sudden cardiac death, and in patients with symptoms.  Long-acting Calcium Channel Blockers are used as well (esp Verapamil). If patient has volume overload, give small doses of diuretics, as patients are preload dependant and low volume is dangerous.  If patients have outflow tract obstruction, septal myectomy is performed.  Septal ablation with ethanol can also be performed.   AICDs are placed in those at high risk for Sudden Cardiac Death.  Remember: Avoid aggressive diuresis as well as digoxin and diuretics.

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