The effects of intracoronary nitroglycerin on left ventricular systolic and diastolic function in man.

The effects of intracoronary (IC) nitroglycerin (NTG) on left ventricular (LV) function were evaluated in 13 patients with significant coronary artery disease.LV cineangiograms were performed in the 40° right anterior oblique projection before and 2 minutes after 0.15 mg NTG was injected directly into the left main coronary artery, and angiographically derived volume and dimensional data were related to simultaneously measured high-fidelity pressures.The diameter of the proximal left anterior descending (LAD) coronary artery was measured from 3-mi injections of contrast material before and after drug administration, and hemodynamic measurements were made 1 and 2 minutes after IC NTG.There was a 22% increase in diameter of the LAD, a small (but significant) and transient rise in heart rate, a more sustained increase in maximal dP/dt and no change in LV end-diastolic pressure, LV systolic pressure or LV volumes.NTG produced no change in global systolic LV function, quantitated as ejection fraction and mean normalized systolic ejection rate, or in regional systolic LV function, measured as 1) shortening velocity and percentage shortening of basal, middle and apical transverse diameters, and 2) segmental ejection fraction.There was also no change in diastolic function evaluated in terms of 1) volume stiffness: slope k of the linear relation between logarithmic pressure and volume, and 2) muscle stiffness: slope ae of the linear relation between logarithmic wall stress and midwall circumference.LV geometry, assessed by ratios of basal, middle and apical transverse diameters to the long axis and slope and intercept of the linear relation between middle diameter/long-axis ratio and volume throughout diastole, likewise was not affected.These results with IC NTG contrast with the previously demonstrated significant effects of sublingual NTG on hemodynamics, systolic and diastolic LV function and LV geometry, and suggest that the major cardiac actions of the drug are indirect.