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.

What Are the Causes of Diastolic Dysfunction?

The primary causes of diastolic dysfunction include chronic high blood presssure, aortic stenosis, coronary artery disease, restrictive cardiomyopathy and aging.

In restrictive cardiomyopathy, abnormal cells, protein, or scar tissue causes infiltration of the heart muscle and it is made stiff. Amyloidosis is the most common cause of restrictive cardiomyopathy in which a disease in which protein-like substance is deposited within the body’s tissues. Sarcoidosis and hemochromatosis are other causes for restrictive cardiomyopathy. The effect of aging is yet to be understood clearly if it alone causes stiffening of the ventricles.

There are many factors that cause damage to the cardiac muscle which leads to dilated cardiomyopathy or heart failure. A few of them are given as follows.

Coronary artery disease. When a coronary artery gets blocked, heart attacks occurs leading to the death of heart muscle cells. Initially, the damage occurs only in the region of muscle supplied by the blocked artery. But within a few months time, the whole left ventricle remodels or dilates to compensate for the damage that has occurred. The amount of ventricular dilation is minimal with a small heart attack. However, with a series of smaller heart attacks, or a large heart attack, the dilated cardiomyopathy becomes intensive, and results in the heart failure. This factor is the most common cause of cardiomyopathy in developed nations.