Arguments supporting the use of calcium antagonists in idiopathic dilated cardiomyopathy: theoretical considerations and clinical results.

There is increasing evidence that sarcolemmal disorders in idiopathic dilated cardiomyopathy (IDC), due either to viral infection, catecholamine excess, ethanol intoxication, microcirculatory disorders, or autoimmune responses, induce enhanced Ca2+ inflow. This may lead to mitochondrial Ca2+ accumulation and activation of phospholipase and proteases, resulting in left ventricular dysfunction. The acute beneficial hemodynamic response to diltiazem in IDC patients, in comparison to other calcium blockers, enabled us to perform an open trial investigating the effects of chronic diltiazem (60-90 mg t.i.d.) in patients with IDC. The results of this trial suggested that adjunctive diltiazem in IDC had beneficial effects on mortality, hemodynamics, and symptoms. Thus a multicenter, double-blind, placebo-controlled trial was initiated.