title: Pharmacologically induced myocardial ischemia: a comparison of dobutamine and dipyridamole.
abstract: The purpose of our study was to compare the ability of dobutamine and dipyridamole infusion to induce myocardial ischemia. In a population of 16 anesthetized open-chest swine, a coronary artery stenosis sufficient to abolish the hyperemic response to a 15-second total occlusion was created. Heart rate, systolic blood pressure, and dP/dt were recorded. Myocardial segment shortening was determined by sonomicrometry in all animals. In a subset of seven animals regional myocardial blood flow was measured by injection of radiolabeled microspheres. Dipyridamole was infused according to a high-dose protocol. After a washout period and reestablishment of a baseline state, dobutamine was infused incrementally. There was no significant difference between the baseline states. Dipyridamole did not affect heart rate but did significantly decrease blood pressure and rate-pressure product. Myocardial segment shortening decreased in the ischemic zone by 0.07 +/- 0.08 (p = 0.004). Dobutamine infusion significantly increased heart rate, blood pressure, and rate-pressure product. Myocardial segment shortening in the ischemic zone decreased by 0.17 +/- 0.09 (p < 0.001). Dobutamine decreased blood flow in the ischemic zone relative to baseline. Both dobutamine and dipyridamole infusion resulted in myocardial ischemia. The magnitude of the ischemic response is greater for dobutamine than for dipyridamole.
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Krannert Institute of Cardiology, Indianapolis, IN 46202-4800, USA.
authors.forename: D S
authors.initials: DS
authors.lastname: Segar
authors.forename: T
authors.initials: T
authors.lastname: Ryan
authors.forename: S G
authors.initials: SG
authors.lastname: Sawada
authors.forename: M
authors.initials: M
authors.lastname: Johnson
authors.forename: H
authors.initials: H
authors.lastname: Feigenbaum
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003250:Constriction; D003326:Coronary Circulation / Q000187:drug effects; D003331:Coronary Vessels; D004176:Dipyridamole / Q000009:adverse effects*; D004280:Dobutamine / Q000009:adverse effects*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D017202:Myocardial Ischemia / Q000139:chemically induced* / Q000503:physiopathology; D013552:Swine; D018487:Ventricular Dysfunction, Left / Q000139:chemically induced / Q000503:physiopathology
chemical_list: D004280:Dobutamine; D004176:Dipyridamole