There are four kinds of cardiac problems caused by HCM are:

  • Diastolic dysfunction
  • Systolic dysfunction
  • Dilated cardiomyopathy
  • Sudden death

“Diastolic dysfunction” refers to the thickened ventricles which become stiff and it becomes more difficult for the ventricles to fill with blood. This stiffness causes the blood to “back up” in the lungs, leading to  shortness of breath with exertion. The diastolic dysfunction also causes arrhythmias, especially atrial fibrillation in patients with with HCM.

“Systolic dysfunction” refers to abnormal pumping action of heart. An insufficient volume of blood is ejected when the heart beats. Systolic dysfunction in HCM is due to abnormal functioning of the mitral or aortic valves, which is caused by the distorted ventricles due to  abnormal thickening of muscle.

Dilated cardiomyopathy occurs late in the course of the disease. The thickened heart muscle  eventually “burns out” leading to heart failure.

Finally, HCM leads to sudden death due to ventricular tachycardia or ventricular fibrillation, causing severe heart fluttering. Sudden deaths may occur during vigorous exertion, or during minimal exertion or at rest, without any warning. The risk of sudden deaths in teens and 20s is high 5% per year.

HCM can be diagnosed by the echocardiogram which is the best method to diagnose HCM. It allows to take accurate measurement of the ventricular walls thickness, and also detects abnormal heart valve function. The electrocardiogram (ECG) also gives indicates the presence of HCM. An echocardiogram should be performed in any person in whom the ECG or the physical examination suggests ventricular hypertrophy. Both and ECG and echocardiogram should be performed in close relatives of a patient diagnosed with HCM.

Although HCM cannot be cured, but it can be managed to reduce the “stiffness” in the thickened heart muscle by use of Beta blockers and calcium blockers. Patients those who have significant heart valve dysfunction, surgery can help to remove parts of the thickened heart muscle if necessary. Atrial fibrillation causes severe symptoms and it has to be managed more carefully in patients with HCM than in the general population.

Sudden death in HCM is typically seen in younger patients even before symptoms are seen, or even before a diagnosis. Many methods including avoiding exercise, using beta blockers and calcium blockers, and using antiarrhythmic drugs have been tried for reducing the risk of sudden death in patients with HCM. But these methods had mixed results. Recently, it has become obvious that in patients with high risk of sudden death, an implantable defibrillator has to be used. The implantable defibrillator is like a pacemaker device which is implanted under the skin. It monitors the heart rhythm continuously. When a dangerous ventricular  arrhythmia occurs, it automatically delivers a shock to the heart to restore a normal rhythm. Although it is  a drastic step, it is much less drastic compared to sudden deaths in young people.

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Filed under: Heart Failure Causes

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