Influence of nifedipine on left ventricular perfusion and function in patients with unstable angina: evaluation with radionuclide techniques.

In 1981, a large, double-blind, randomized trial was started in The Netherlands to evaluate the therapeutic effects of nifedipine and/or metoprolol in patients with unstable angina. This study has been called the Holland Interuniversity Nifedipine/metoprolol Trial (HINT) and required several hundred patients to establish potential therapeutic effects. From December 1982 to January 1984 the effects of nifedipine on left ventricular (LV) performance in a subgroup of 52 HINT patients were studied using radionuclide techniques. All patients (23 on nifedipine, 29 controls) underwent thallium-201 scintigraphy or radionuclide angiography just before and 48 h after the start of experimental medication. The radionuclide angiographic studies were also performed at 1 and 4 h after treatment. Nifedipine did not influence the incidence or disappearance of perfusion defects on the 48-h thallium images. No significant differences in overall LV ejection fraction (EF) were seen at any time between nifedipine-treated patients and controls. However, paired observations in 37 patients showed improvement of LVEF after 48 h in 8 patients on nifedipine and in only 1 control patient. Scintigraphic measurements on admission were not related to clinical outcome after 48 h. Concomitant administration of metoprolol did not influence LVEF in either group. It is concluded that nifedipine improves LVEF after 48 h in a subset of patients with unstable angina without affecting myocardial perfusion. This finding indicates that nifedipine has a predominant effect on afterload reduction in patients with unstable angina. However, early scintigraphic measurements had no significant predictive value for subsequent cardiac events.