[Changes in diastolic ventricular properties by intravenous nifedipine infusion in patients with unstable angina pectoris].

In 16 patients with unstable angina pectoris 2 mg of nifedipine were infused intravenously for 1 hour. From coronary angiograms and cineventriculograms before and after nifedipine infusion vessel and stenosis diameters and global and regional left ventricular function were determined. Pressures in the left ventricle (Millar catheter tip manometer), aorta and pulmonary artery were measured continuously. Intravenous nifedipine infusion decreased left ventricular systolic pressure from 131.9 +/- 15.3 to 119.1 +/- 18.6 mm Hg (p less than 0.001) and mean aortic pressure from 94.4 +/- 13.6 to 85.8 +/- 15.0 mm Hg (p less than 0.01) and increased heart rate from 70.6 +/- 10.6 to 77.5 +/- 10.4, with no change in pressure rate product. Left ventricular volumes declined significantly (EDVI from 94.4 +/- 16.7 to 79.4 +/- 17.1 ml/m2 p less than 0.001, ESVI from 34.2 +/- 9.3 to 27.2 +/- 10.4 ml/m2 p less than 0.001). Ejection fraction increased slightly from 63.2 +/- 7.8 to 66.2 +/- 9.4% (p less than 0.05). Regional wall motion did not change, either in ischemic or in normally perfused areas. A change in coronary vessel or stenosis diameter was not observed. There was a remarkable 46% decrease in left ventricular enddiastolic pressure (from 11.1 +/- 5.1 to 6.0 +/- 2.3 mmHg, p less than 0.001) which developed slowly and not parallel in time to the afterload reduction. The cause appears to be the normalization of an increased left ventricular compliance documented by a significant decrease of the late diastolic dp/dV from 0.35 +/- 0.22 to 0.07 +/- 0.02 mm Hg (p less than 0.001) after nifedipine infusion. This implicates a direct myocardial effect of calcium antagonists on the ischemic myocardium.