Cardiomyopathy (including peripartum cardiomyopathy and alcoholic cardiomyopathy), which involves dilation or enlargement of the heart’s ventricles and an increase in the size of the heart overall. This condition may be caused by heart disease, viruses, abuse of illicit drugs and alcohol, and genetic disorders. Additionally, idiopathic dilated cardiomyopathy (also called dilated cardiomyopathy of unknown cause) is not uncommon. Dilated cardiomyopathy causes about 10,000 deaths annually in the United States and is a major cause for heart transplantation.
Cardiomyopathy refers to diseases of the heart muscle. These diseases enlarge your heart muscle or make it thicker and more rigid than normal. In rare cases, scar tissue replaces the muscle tissue. Some people live long, healthy lives with cardiomyopathy. Some people don’t even realize they have it. In others, however, it can make the heart less able to pump blood through the body. Cardiomyopathy is a disease of the heart muscle. There are three main types of cardiomyopathy – dilated, hypertrophic and restrictive – all of which affect your heart’s muscle, often making it difficult to pump blood and deliver it to the rest of your body. There are many causes of cardiomyopathy, including coronary artery disease and valvular heart disease.
About 20-30% of dilated cardiomyopathy cases have been reported as familial, although with incomplete and age-dependent penetrance, and linked to a diverse group of more than 20 loci and genes. Although genetically heterogeneous, the predominant mode of inheritance for dilated cardiomyopathy is autosomal dominant, with X-linked, autosomal recessive, and mitochondrial inheritance less frequent.
Cardiomyopathy can be caused by viral infections, heart attacks, alcoholism, long-term, severe high blood pressure, nutritional deficiences (particularly selenium, thiamine, and L-carnitine), systemic lupus erythematosus, celiac disease, and end-stage kidney disease.
The most common cause of cardiomyopathy in developed nations is coronary artery disease. Heart attacks cause death of heart muscle by obstruction of a coronary artery. While the damage is localized to the region of muscle supplied by that artery, within a few months the entire left ventricle dilates (or remodels) to compensate for the damage. With a small heart attack, the amount of ventricular dilation is minimal.
The symptoms of cardiomyopathy include shortness of breath on exertion, dizziness, fainting and angina pectoris. (Angina is chest pain or discomfort caused by reduced blood supply to the heart muscle.) Some people have cardiac arrhythmias. These are abnormal heart rhythms that in some cases can lead to sudden death. Often an implanted cardioverter defibrillator (ICD) is needed to shock the heart to restart a normal heart rhythm and prevent sudden dealth. The obstruction to blood flow from the left ventricle increases the ventricle’s work, and a heart murmur may be heard.
Antiarrhythmic drugs may be given to prevent abnormal heart rhythms. Most of these drugs are prescribed in small doses. Doses are increased in small increments, because if the dose is too large, an antiarrhythmic drug may worsen heart rhythm abnormalities or depress pumping function. Some people have an abnormality of the electrical conduction in the heart, which can be helped by a pacemaker. Doctors may consider an implantable cardioverter-defibrillator pacemaker in patients with persistent poor heart function and an increased risk of sudden death.