What are some causes of dilated cardiomyopathy and restrictive cardiomyopathy?
Cardiomyopathies are diseases that involve primary dysfunction of the heart muscle. This broad collection of diseases can be divided on a pathophysiologic basis into dilated, hypertrophic, and restrictive subtypes, with some overlap occurring between these categories. A few causes of dilated cardiomyopathy include previous myocarditis related to viral infection (especially by coxsackievirus B and cytomegalovirus), and toxic exposure (e.g., cocaine, alcohol, and doxorubicin). Causes of restrictive cardiomyopathy include infiltrative systemic disorders such as sarcoidosis, amyloidosis, eosinophilic cardiomyopathy (Löffler syndrome), and Fabry disease. On MRI, nonischemic cardiomyopathy may show midmyocardial or subepicardial delayed enhancement not corresponding to a coronary artery distribution.