Dilated Cardiomyopathy

It is a condition in which the heart's ability to pump blood is decreased because the heart's main pumping chamber, the left ventricle, is enlarged and weakened. In some cases, it prevents the heart from relaxing and filling with blood as it should. It is a condition in which the heart becomes enlarged and cannot pump blood efficiently. The decreased heart function can affect the lungs, liver, and other body systems. DCM is one of the cardiomyopathies, a group of diseases that affect primarily the myocardium.

Symptoms: Dilated cardiomyopathy may not cause symptoms significant enough to impact on quality of life. These may include:  Shortness of breath  Syncope  Angina, but only in the presence of ischemic heart disease  A person suffering from dilated cardiomyopathy may have an enlarged heart, with pulmonary edema and an elevated jugular venous pressure and a low pulse pressure. Signs of mitral and tricuspid regurgitation may be present. A fast heart rate with no change during the respiratory cycle may also be found.

Diagnosis: Enlargement of the heart is seen upon normal chest X-ray. Pleural effusion may also be noticed, which is due to pulmonary venous hypertension. The electrocardiogram often shows sinus tachycardia or atrial fibrillation, ventricular arrhythmias, left atrial enlargement, and sometimes intraventricular conduction defects and low voltage. Echocardiogram shows left ventricular dilatation with normal or thinned walls and reduced ejection fraction. Genetic testing can be important. The results of the genetic testing can help the doctors and patients understand the underlying cause of the dilated cardiomyopathy. Cardiac magnetic resonance imaging (cardiac MRI) may also provide helpful diagnostic information in patients with dilated cardiomyopathy. Treament: Standard therapy may include salt restriction, ACE inhibitors, diuretics, and digitalis. Anticoagulants may also be used. Alcohol should be avoided. Other supplements provided may include L-carnitine, taurine and D-ribose.

Pathophysiology: DCM is primarily a failure of systolic function with inadequate contractility (pump failure). The affected myocardium is unable to generate the pressures required to maintain cardiac output. As a consequence the ventricles become stretched and volume overloaded. As well as systolic failure there is diastolic failure, as the ventricles become non-compliant, failing to relax and compromising ventricular filling. Eventually the AV rings become stretched and the AV valves fail to coapt properly. This allows regurgitation of blood into the atria.

Epidemology: Among the cardiomyopathies,--dilated cardiomyopathy (dcm), hypertrophic cardiomyopathy, restrictive cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy--, dcm is the most frequent entity. Its prevalence in the United States amounts to 36 cases per 100,000 inhabitants, men being almost 3-fold more involved than women. In 20 to 30% of the cases of idiopathic dcm a genetic transmission of the disease has been found. Another 20 to 30% of idiopathic dcm are associated with inflammatory and immunological phenomena.