Original Article: PDF OnlyEffects of Spiraprilat, an Angiotensin-Converting Enzyme Inhibitor, on Anesthetized Dogs in a New Model of Acute Left Ventricular FailureNakazawa, Mikio; Ishihara, Tukasa; Takahashi, Yoshiki; Okuhira, Masayasu; Imai, ShoichiAuthor Information Department of Pharmacology, Niigata University School of Medicine, Niigata, Japan Journal of Cardiovascular Pharmacology: October 1993 - Volume 22 - Issue 4 - p 585-593 Free Abstract Summary Spiraprilat, a new angiotensin-converting enzyme (ACE) inhibitor, was compared with enalaprilat for its ability to improve left ventricular (LV) function and metabolism in anesthetized open-chest dogs with a new model of acute LV failure (ALVF) induced by embolization of the left coronary artery with 50 μm plastic micro-spheres followed by intravenous (i.v.) infusion of methoxamine. With this procedure, LV end-diastolic pressure (LVEDP) increased from 4.2 ± 0.7 to 12.8 ± 1.3 mm Hg and remained at ±12 mm Hg throughout the experiment. Cardiac output (CO) decreased from 1.25 ± 0.12 to 0.79 ± 0.06 and 0.55 ± 0.02 L/min at 30 and 90 min after meth-oxamine infusion, respectively. L±dP/dtmax and dP/dt/P decreased, while total peripheral resistance (TPR) increased. These hemodynamic changes indicated establishment of stable ALVF of a moderate degree. More over, decreases in myocardial lactate consumption and contents of creatine phosphate in the myocardium indicated the existence of moderate ischemia. The new ACE inhibitor, spiraprilat, as well as enalaprilat (30 μg/kg i.v.) effectively decreased mean aortic pressure (30%), LVEDP (20%), and TPR (30%) and increased stroke volume (SV) CO, and dP/dt/P. Both agents decreased myocardial oxygen consumption (20%) and caused a significant increase in myocardial creatine phosphate contents. These data indicate that the beneficial effects of both inhibitors extended not only to LV function but also to myocardial energy metabolism in ALVF. © Lippincott-Raven Publishers.