The symptoms and signs of heart failure, commented above, do not guarantee the diagnosis of dilated cardiomyopathy. The electrocardiogram does also not guarantee the diagnosis, because it may be normal or show nonspecific signs of atrial enlargement and / or ventricular hypertrophy. The chest radiograph is usually abnormal, showing an increased heart size and sometimes signs of congestion and / or pulmonary edema. Echocardiography is the best technique for assessing patients with dilated cardiomyopathy, since it permits the visualization of ventricular dilatation and decreased ventricular contractility. Coronary arteriography is normal or findings are unrelated to the decreased contractility in the idiopathic dilated
