title: Effects of nitroglycerin on left ventricular diastolic properties in man.
abstract: The effects of nitroglycerin (NTG) on left ventricular (LV) isovolumic relaxation and diastolic function were studied in 12 patients with coronary artery disease: in 6 patients after 0.8 mg sublingual (sI) NTG and in 6 patients after 0.15 mg intracoronary (ic) NTG. From high-fidelity LV pressure peak positive and negative dP/dt, LV systolic (LVSP) and end-diastolic pressure (LVEDP) were measured. The time constant T of isovolumic pressure decay was derived from P = a X exp(-t/T) + c. From simultaneous diastolic pressures and volumes, pressure-volume curves were obtained throughout diastole. In an additional 14 patients, the effects of 0.15 mg ic NTG on coronary sinus blood flow (CSBF) and end-diastolic (ED) and end-systolic septal thickness (ESST) were evaluated. SI NTG produced an increase in heart rate and a decrease in LVSP, LVEDP and negative dP/dt. These effects were associated with a decrease in T and a downward shift of the pressure-volume relation. In contrast, ic NTG caused no change in heart rate, LVSP and LVEDP. The LV pressure-volume relation was not altered although T decreased. Ic NTG produced an early rise in CSBF and a sustained increase in EDST and ESST. Data indicate that sI NTG increases the speed of isovolumic relaxation and improves diastolic function, but these actions are not reflected by negative dP/dt due to its dependence on multiple hemodynamic factors. Ic NTG accelerates isovolumic relaxation, but has no measurable effects on later diastolic function. The increase in positive dP/dt may be explained by an engorgement of the coronary vasculature resulting in stretching of the myocardial fibers.
mesh_terms: D001794:Blood Pressure / Q000187:drug effects; D003971:Diastole / Q000187:drug effects*; D006801:Humans; D009200:Myocardial Contraction / Q000187:drug effects*; D005996:Nitroglycerin / Q000494:pharmacology*
chemical_list: D005996:Nitroglycerin