Effect of short and long term administration of amiodarone on ischaemia-induced left ventricular dysfunction. Implications for combined antianginal drug therapy.

To asses haemodynamic effects of short and long term amiodarone on ischaemia-induced left ventricular dysfunction and to compare them with those of glyceryl trinitrate (nitroglycerin), beta-blocking and calcium antagonist drugs, 19 patients with chronic ischaemic heart disease were studied. All patients underwent simultaneous right heart catheterisation and equilibrium radionuclide angiocardiography at rest and during symptom-limited supine bicycle exercise. After control measurements without antianginal therapy, 10 patients received 7.5 mg/kg amiodarone intravenously over 5 minutes (short term study) followed by oral administration of amiodarone for 3 weeks (long term study). The remaining 9 patients were studied following the randomised administration of glyceryl trinitrate (0.8 mg sublingually), metoprolol (0.15 mg/kg intravenously) and nifedipine (5 ng/kg/min). During exercise known to provoke angina pectoris without therapy (control study), amiodarone improved myocardial oxygen consumption by reducing heart rate and systolic blood pressure without the negative inotropic effects seen after acute beta-adrenoceptor blockade. Comparisons with the haemodynamic profiles of other antianginal drugs suggest that amiodarone may be most effective when combined with glyceryl trinitrate or nifedipine for the treatment of ischaemic left ventricular dysfunction.