[Role of calcium antagonists in the pharmacologic treatment of heart insufficiency].
There has been increasing interest in the use of calcium antagonists as arterial vasodilator agents in the management of patients with congestive heart failure. Because congestive heart failure is mostly secondary to coronary artery disease, calcium antagonist drugs seem particularly appealing because of their anti-ischemic properties. The potent vasodilating action of calcium antagonists decreases impedance and improves ejection phase indexes of left ventricle function. However, these drugs interfere with calcium availability for myocardial contraction, and concern has been expressed about their potential depressant effect on myocardial performance. The net hemodynamic effect depends on the relative vascular versus myocardial potency of each calcium antagonist and on the indirect effects of reflex sympathetic activation. Balance between these factors is still influenced by the intrinsic status of left ventricle of the patient. Generally, the negative inotropic direct effect of the calcium antagonists is counteracted by the beneficial influence of the decrease of systemic vascular resistance. Because of its relatively more pronounced negative inotropic action, verapamil is not advisable in patients with left ventricular failure. Limited experience with diltiazem show no significant negative inotropic action. Nifedipine has been studied in its acute and long term effects. The use of sublingual nifedipine is established in the emergency management of acute pulmonary edema, specially in patients with arterial hypertension, or when acute ventricular dysfunction is associated with mitral or aortic insufficiency. Patients with chronic congestive heart failure have shown after nifedipine an increase in stroke volume and cardiac index at rest and during exercise, as well as decreases of pulmonary capillary wedge pressure during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)
de Sá
M E
ME
D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D004095:Dihydropyridines / Q000627:therapeutic use; D004110:Diltiazem / Q000627:therapeutic use; D006333:Heart Failure / Q000188:drug therapy*; D006801:Humans; D009543:Nifedipine / Q000627:therapeutic use; D014700:Verapamil / Q000627:therapeutic use
D002121:Calcium Channel Blockers; D004095:Dihydropyridines; D014700:Verapamil; D004110:Diltiazem; D009543:Nifedipine
O lugar dos antagonistas do cálcio na terapêutica farmacológica da insuficiência cardíaca.