Calcium-channel blockade in the management of severe chronic congestive heart failure: a bridge too far.

Because vasodilator therapy has become an established approach to the treatment of patients with severe chronic heart failure, there has been increasing interest in the use of the calcium channel-blocking drugs in the management of this disorder. This approach has particular appeal because approximately 60% of patients with heart failure have severe left ventricular dysfunction associated with coronary artery disease, and left ventricular systolic and diastolic performance in these patients may improve after interventions directed at improving myocardial blood flow. Unfortunately, all available calcium channel-blocking drugs possess potent negative inotropic effects; these are normally offset in patients without heart failure by activation of the sympathetic nervous system. Patients with severe left ventricular dysfunction, however, are exquisitely dependent on the transmembrane transport of calcium for maintenance of contractile function and show marked attenuation of adrenergic reflexes, which can no longer serve a homeostatic support function; hence, such patients are likely to experience notable cardiodepressant effects after calcium-channel blockade. In clinical trials, although some patients with severe chronic heart failure have been reported to benefit from short-term calcium-channel blockade, the hemodynamic benefits seen are modest compared with those from conventional vasodilator drugs, and little long-term improvement has been observed in randomized, double-blind trials. In addition, 10% to 40% of patients who receive short- and long-term therapy with verapamil, nifedipine, and diltiazem show evidence of serious hemodynamic or clinical deterioration.(ABSTRACT TRUNCATED AT 250 WORDS)