What is Cardiomyopathy?
Cardiomyopathy is a general term for diseases of the heart muscle (myocardium) that impair its ability to circulate the blood. The cardiomyopathies are not the result of hypertension, congenital heart problems, diseases of the valves, or the coronary arteries. Unlike many heart diseases that are typically associated with aging, cardiomyopathy strikes people of all ages, and very commonly young people. There are two forms: primary and secondary cardiomyopathies. Both forms are diseases of the heart muscle. The primary form has no known cause and the secondary has a known cause or is associated with diseases of other organ systems.
A more useful classification is to describe the disease based on its clinical presentation. This classification describes the cardiomyopathy as dilated (congestive), hypertrophic, or restrictive. They vary greatly in symptoms and treatment.
The causes of dilated cardiomyopathy can be unknown (idiopathic). Secondary causes are infections, toxins (commonly alcohol and cocaine), endocrine problems such as diabetes and thyroid disease, nutritional, neuromuscular diseases like muscular dystrophy, genetic/familial disease, or as a complication of pregnancy or childbirth (peripartum cardiomyopathy). Dilated cardiomyopathy is found most often in middle-aged men. It is also seen in females following pregnancy.In hypertrophic cardiomyopathy, the heart is enlarged, but the heart findings are reversed. The muscular walls are extremely thick, creating less room inside the ventricular cavities. This condition often has a negative effect on the mitral valve and the septum (the wall between the two ventricles). Hypertrophic cardiomyopathy is inherited in about 50% of cases, and found mostly in individuals between 20 and 40 years old.
Restrictive cardiomyopathy, the least common form of this disease, is typically a complication of amyloidosis, a disorder that is associated with cancers of the blood. It can be difficult to distinguish restrictive cardiomyopathy from constrictive pericarditis, which is curable with surgery.
How is it diagnosed?
History: Individuals with dilated cardiomyopathy may report shortness of breath (dyspnea) on exertion, breathing difficulties while lying down (orthopnea), or sleeping (paroxysmal nocturnal dyspnea), fatigue, and occasionally palpitations.
Many individuals with hypertrophic cardiomyopathy, especially children and young adults, have no symptoms of the disease. The disease is discovered after a sudden death on post-mortem examination. Symptoms in other individuals include shortness of breath, dizziness or fainting, chest pain, and an awareness of heart palpitations.
Shortness of breath (dyspnea) on exertion and fatigue are the most prominent symptoms of restrictive cardiomyopathy. Other symptoms include an increased abdominal girth, swelling of the feet and ankles, and upper abdominal discomfort due to swelling of the liver. In individuals with restrictive cardiomyopathy secondary to infiltrative diseases such as amyloidosis and sarcoidosis, syncope (fainting) or near syncope and sudden death may be the presenting symptom.
Cardiomyopathy signs and symptoms
If cardiomyopathy is extensive enough to cause congestive heart failure, the following symptoms may occur:
- Irregular or rapid heartbeat.
- Shortness of breath with activity.
- Swelling of the feet and ankles.
- Cough with frothy, bloody sputum.
- Appetite loss.
- Loss of sex drive.
Physical exam: The individual with dilated cardiomyopathy often appears breathless and pale and has a difficulty in breathing while lying recumbent. Tachycardia (fast heart rate) and extra beats (ectopic beats) while listening to the heart are common. There may be wheezing and other chest findings consistent with heart failure.
The only finding on physical exam in individuals with hypertrophic cardiomyopathy may be a systolic heart murmur that changes in character with different physical tests (squatting, Valsalva maneuver) and stressing the heart with drugs such as amyl nitrate or nitroglycerin.
Common physical findings with restrictive cardiomyopathy are swelling of the ankles and feet, fluid in the abdomen (ascites), and an enlarged tender liver. The heart sounds are distant with extra sounds (gallops).
Tests: An electrocardiogram, angiogram, chest x-ray, and echocardiogram may be necessary to confirm diagnosis of cardiomyopathy. Cardiac catheterization with myocardial biopsy is an option when the diagnosis is unclear.
How is Cardiomyopathy treated?
Individuals with dilated cardiomyopathy are often started on drug therapy, which may include digitalis, vasodilators, diuretics, and steroids.
Cardiomyopathies attributable to infections are treated with the appropriate antimicrobials.
Treatment may include anticoagulants to reduce the risk of blood clots. Some individuals may not respond to drug therapy.
A heart transplant is indicated in the most serious case, if all the other criteria for transplantation surgery are met.
The drug regimen for hypertrophic cardiomyopathy often adds beta-receptor and calcium channel blockers. If the treatment is not successful, the individual may benefit from implantation of a defibrillator device. Some individuals may require surgery to remove excess myocardial tissue in the intraventricular septum. Although the procedure has a mortality rate of about five-percent, the majority of individuals see dramatic, long-term improvement. In rare cases, a heart transplant is recommended. In individuals with restrictive cardiomyopathy, drug therapy is usually attempted but is often unsuccessful. Most individuals who display signs of heart failure die within a year. In addition to the specific therapies outlined above, individuals with all types of cardiomyopathy are usually urged to make lifestyle changes. Restriction of salt and abstention from alcohol are important dietary changes. Obesity must be addressed. Cessation of smoking reduces the workload on the heart.
What might complicate it?
In dilated cardiomyopathy, the heart is enlarged with flabby, weak walls and significantly dilated ventricles. Because the heart pumps so poorly, clots (thrombi) often develop in the heart. This increases the individual's risk of stroke and other embolic phenomena attacks. Hypertrophic cardiomyopathy can result in the condition known as atrial fibrillation. These individuals are at risk of forming thrombi in the left atrium with the same risk of complications seen with dilated cardiomyopathy. Though the individuals with restrictive cardiomyopathy need diuretics to help with right-sided heart failure, they are at risk of developing hypotension, even with careful monitoring. Whatever the cause or type of cardiomyopathy, any individual with cardiomyopathies is more prone to complications from pneumonia and other systemic diseases that are less innocuous in healthy individuals. This overview of possible complications is by no means comprehensive.
The prognosis for individuals with dilated cardiomyopathy depends in large part on their age and whether the disease is considered to be of recent onset. The majority of individuals, especially when they are 55 or older at diagnosis, die within a few years. Younger individuals may do quite well, either because of spontaneous reversal or because of drug therapy. Both hypertrophic and restrictive cardiomyopathies have high mortality rates.
Dilated cardiomyopathy is similar to the findings seen in cases of congestive heart failure secondary to ischemic heart disease. Hypertensive heart disease presents similarly and has many of the same symptoms and signs of hypertrophic cardiomyopathy. Restrictive cardiomyopathy is difficult to distinguish from constrictive pericarditis.
Cardiologist and cardiovascular surgeon.
Notify your physician if
- You or a family member has symptoms of cardiomyopathynor symptoms recur after treatment.
- You have chest pain.
- New, unexplained symptoms develop. Drugs used in treatment may produce side effects.
Last updated 3 April 2018