Arrhythmias are not cardiomyopathies, but are abnormalities in the frequency or rhythm of the heartbeat caused by the origin of the heart activity or by conduction disorders. Arrhythmias are an important group of cardiovascular diseases that can develop alone or in association with other cardiovascular diseases. Cardiomyopathies are a group of cardiovascular diseases that are mainly caused by myocardial lesions, and are clinically characterized by abnormalities in the mechanical and electrical activity of the heart caused by different etiologies. Severe cardiomyopathy can cause cardiovascular death or progressive heart failure, and arrhythmia can also be a clinical manifestation of cardiomyopathy.