Cardiomyopathy II: Dilated Cardiomyopathy

Dilated cardiomyopathy, or DCM, is a progressive disorder of the myocardium marked by the dilation of the ventricular chambers and impaired contractile function.

While many cases of DCM are idiopathic, the condition can also result from myocardial insults such as hypertension, coxsackievirus B infections, chemotherapeutic agents like doxorubicin, and endocrine disorders such as thyrotoxicosis.

DCM is characterized by diffuse myocardial damage, which can include inflammation, fibrosis, and loss of myocardial cells.

These changes lead to ventricular dilation, impaired systolic function, atrial enlargement, and blood stasis in the left ventricle, which in turn causes cardiomegaly and contractile dysfunction.

Next, clinical manifestations of DCM include reduced exercise capacity, fatigue, palpitations, dyspnea at rest, abnormal S3 and S4 heart sounds, arrhythmias, heart murmurs, pulmonary crackles, and edema.

Lastly, DCM can be diagnosed by chest X-ray, which reveals cardiomegaly. An ECG may show arrhythmias and elevated B-type natriuretic peptide levels can indicate cardiac failure.