Hemodynamic effects of nitroglycerin combined with diltiazem in patients with coronary artery disease

Resting coronary and left ventricular hemodynamic effects of diltiazem and nitroglycerin, given intravenously in combination, were studied in 12 patients with coronary heart disease. Results observed with this combination were compared with those in seven patients given diltiazem initially (group I) and five patients given nitroglycerin initially (group II). The diltiazem-nitroglycerin combination reduced systolic blood pressure 27 percent (p less than or equal to 0.05) with no significant change in heart rate to affect a 22 percent (p less than or equal to 0.05) decrease in the rate-pressure product. Left ventricular end-diastolic pressure (-36 percent) and dp/dt (-6.4 percent) both declined (p less than or equal to 0.05). Coronary flow and cardiac output were both maintained. Diltiazem alone and nitroglycerin alone also reduced systolic pressure and the rate-pressure product but to a lesser degree than the combination. Diltiazem did not significantly affect left ventricular end-diastolic pressure and dp/dt. Nitroglycerin reduced left ventricular end-diastolic pressure to an extent similar to the reduction produced by the combination but increased heart rate whereas this determinant of myocardial oxygen demand did not increase significantly with the combination. These findings suggest that the combination of diltiazem and nitroglycerin produces a greater reduction in myocardial oxygen demand than either drug alone. In addition, the combination maintains coronary blood flow without increases in determinants of myocardial oxygen demand. This potentially beneficial drug combination warrants further trial in patients with myocardial ischemia.