There are several types of cardiomyopathy, all affecting the myocardium or muscle tissue of the heart. Damage prevents the heart from functioning normally, or the walls of the tissue thickens or hardens, causing the heart to resist filling to capacity. Cardiomyopathy progresses in most cases, and is one of the main diseases requiring heart transplant.
The different forms are all relatively rare with about a tenth of a percent occurrence in the general population. One form of cardiomyopathy is called ischemic because the cause is repeated heart attacks or strokes. Non-ischemic cardiomyopathy includes three main types where the cause may not always be clear. These are hypertrophic cardiomyopathy, dilated cardiomyopathy, and restricted cardiomyopathy. Arrhythmogenic right ventricular dysplasia (ARVD) is a fourth rare type of genetic origin.
Dilated cardiomyopathy is the most common form, causing enlargement of both of the heart's ventricles, or pumping chambers. The enlargement weakens the heart and may cause eventual heart failure. Early stage dilated cardiomyopathy may be treated with medications like digitalis, or medications that lower blood pressure. Ultimately, however, this form of heart muscle disease normally requires transplant. Main causes include extreme alcoholism, viral diseases, or genetic predisposition.
When family history includes others with dilated cardiomyopathy, genetics may be considered as the primary cause. Viruses indicated in dilated cardiomyopathy are rheumatic fever and Kawasaki’s Syndrome. Often causal viruses are mild and may go unnoticed.
Hypertrophic cardiomyopathy causes additional heart muscle tissue to grow on the septum, the dividing wall between the two ventricles. This reduces the size of the left ventricle, which is responsible for pumping blood to the body. Symptoms are generally mild at first, but may progress over time.
Medications can increase heart function, and often an implanted pacemaker or defibrillator controls heart rhythms, since this condition carries with it the risk of sudden arrhythmia death. When risk is minimized, many with hypertrophic cardiomyopathy have an excellent life expectancy. However, if the disease progresses, cardiologists may perform an ablation, which uses alcohol to burn off some of the extra heart muscle.
Restricted cardiomyopathy is relatively rare.. The heart muscles enlarge causing the ventricles to become rigid, and unable to allow the heart to fill properly. This type tends to progress, with many needing a transplant. At onset, the primary goals are to eliminate dangerous arrhythmias and to increase heart function.
Arrhythmogenic right ventricular dysplasia is a genetic disease. The right ventricle, which pumps blood to the lungs, loses muscle tissue, which is then replaced by fat tissue. This type of cardiomyopathy, though very rare, is one of the leading causes of sudden death in athletes. Usually, an affected person is asymptomatic until he or she presents with heart failure. Medications and pacemaker implantation may be used together to reduce heart failure.
Risk of passing ARVD onto children is high, approximately 50%. It is advisable if one has a parent with ARVD to see a cardiologist to evaluate whether this condition is present in oneself. Early diagnosis can help slow the disease, and also be important when considering having one’s own children. Either parent can pass the disease to a child, and pregnancy may be complicated if one has ARVD.
Though there is currently no cure for cardiomyopathy, researchers hope that gene therapy may someday play a role in reducing abnormal heart tissue. As well, transplant technology continues to improve, increasing life expectancy. However, lack of donor hearts often makes transplant impossible, and many die waiting for a heart. Increased donor registry is encouraged to help make transplantation possible for all who need a heart.