Effects of intracoronary nicardipine and nifedipine on left ventricular function and coronary sinus blood flow

1 To determine the relative effects of nifedipine and nicardipine on left ventricular inotropy we directly injected into the left main coronary artery, in 12 patients with coronary artery disease, 20 min apart and in random order, 0.2 mg of each drug, which had previously been shown to increase coronary sinus blood flow equally. All variables were recorded at time (min), 1 through 5 and 7.5 and 10 min after injection. 2 Coronary sinus blood flow was increased by both drugs to the same extent (54% vs 56%). 3 Peak (+) and peak (–) dP/dt, and (dP/dt)/DP40 were affected by both drugs after 1 min, but by nifedipine to a significantly larger extent (P < 0.001, P < 0.001 and P < 0.005 respectively). 4 Left ventricular end-diastolic pressure was also increased by both drugs, but again was more pronounced after nifedipine (79% vs 30%, P < 0.001). 5 Left ventricular systolic pressure, mean aortic pressure and pulmonary artery pressure were not affected by nicardipine in contrast to nifedipine. 6 At doses that increased coronary sinus blood flow to a similar extent, nicardipine, in contrast to nifedipine, showed little effect on left ventricular inotropy.