The effects of glyceryl trinitrate, isosorbide dinitrate and sodium nitroprusside on haemodynamics, coronary blood flow and myocardial oxygen consumption - an experimental study.
The influences of glyceryl trinitrate, isosorbide dinitrate and sodium nitroprusside intravenously on haemodynamics, coronary circulation and myocardial oxygen consumption were investigated in closed chest dogs (n = 8). In an attempt to simulate heart failure the dogs received blood transfusion (15 ml/kg) in the presence of halothane-induced myocardial depression. All three nitrates reduced the loads for the left ventricle. With isosorbide dinitrate and sodium nitroprusside the preload and pulmonary pressure decreased to a greater extent than with glyceryl trinitrate. The haemodynamic results suggest that sodium nitroprusside is the favourable nitrate in left ventricular failure because it produces a balanced reduction in the ratio of pre- and afterload. Four micrograms/kg X min sodium nitroprusside induced marked coronary dilatation; glyceryl trinitrate had only a slight coronary vasodilating effect. With isosorbide dinitrate the myocardial blood flow remained well adapted to oxygen demand, the coronary vascular resistance did not change. Sodium nitroprusside produced a significant change of the transmural myocardial blood distribution-expressed as the epi/endocardial blood flow ratio. The ratio was increased by sodium nitroprusside, much more than by glyceryl trinitrate or isosorbide dinitrate.
D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects; D004285:Dogs; D005292:Ferricyanides / Q000494:pharmacology*; D006439:Hemodynamics / Q000187:drug effects*; D007548:Isosorbide Dinitrate / Q000494:pharmacology*; D009206:Myocardium / Q000378:metabolism; D005996:Nitroglycerin / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects
D005292:Ferricyanides; D009599:Nitroprusside; D005996:Nitroglycerin; D007548:Isosorbide Dinitrate