Hemodynamic effects of intravenous diltiazem in patients with recent myocardial infarction

The hemodynamic effects of intravenous diltiazem, 0.2 mg/kg, were examined in eight patients with recent myocardial infarction. Diltiazem lowered mean aortic pressure (87.0 +/- 3.3 to 79.9 +/- 3.1 mmHg, P less than 0.01) and systemic vascular resistance (1353.0 +/- 136.2 to 964.9 +/- 101.7 dynes.sec.cm-5, P less than 0.01), and increased cardiac index (3.77 +/- 0.27 to 4.72 +/- 0.41 liters/min/sq m, P less than 0.01) and stroke index (57.5 +/- 4.5 to 69.4 +/- 7.6 ml/beat/sq m, P less than 0.05). No significant changes in the left ventricular end-diastolic, right atrial, and pulmonary arterial pressure, or heart rate were noted after diltiazem. These results suggest that the negative inotropic effects of diltiazem are negligible even in patients with recent myocardial infarction. The electrocardiogram should be observed carefully, however, since the PR interval was further prolonged in one patient who had first-degree atrioventricular block before diltiazem.