Effects of nitroglycerin on hemodynamics in dogs with experimentally inserted heartworms

Hemodynamic effects of nitroglycerin were investigated in dogs with right ventricular failure including engorgement of the pulmonary artery and ascites induced by insertion of adult live heartworms into the pulmonary artery. The mean pulmonary arterial pressure (21.5 +/- 6.6 mmHg) in heartworm-inserted dogs 4 or 5 weeks after heartworm insertion were higher than that of control (4.2-7.1 mmHg). Nitroglycerin administered intravenously at doses of 3 or 10 micrograms/kg decreased pulmonary arterial pressure in these heartworm inserted dogs. This drug also decreased pulmonary vascular resistance and total systemic resistance with no effect on cardiac index and heart rate.