Effects of tiapamil on myocardial performance in coronary artery disease.

Tiapamil has been extensively investigated for treatment of cardiac arrhythmias. Concern persists, however, that, as a calcium antagonist, it may seriously depress myocardial function. To investigate this possibility, 20 patients were given tiapamil intravenously and studied by radionuclide ventriculography. Tiapamil markedly lowered arterial pressure. Left ventricular ejection fraction increased from 54 +/- 3.3 to 57 +/- 3.3%. No significant change in heart rate was noted. Tiapamil did not increase the extent of left ventricular asynergy. The potent vasodilator properties of tiapamil compensate for any intrinsic decrease in left ventricular contractibility, and therefore overall cardiac function is not worsened by the drug in patients with normal or moderately reduced resting ventricular ejection fractions.