Effects of specific bradycardic agents on exercise-induced regional myocardial dysfunction in dogs.
Alinidine and ULFS 49, two specific bradycardic agents were comparatively investigated with propranolol in a model of exercise-induced regional myocardial contractile dysfunction in dogs. Standardized treadmill exercise resulted in a marked decrease in regional function in the myocardium supplied by the critically stenosed circumflex branch of the left coronary artery. All three drugs prevented exercise-induced myocardial dysfunction. The effect on the exercise-induced increase in heart rate and left ventricular dp/dt, however, suggests different modes of action. Propranolol prevents dysfunction by a marked negative inotropy and negative chronotropy, alinidine by a marked negative chronotropy and moderate negative inotropy, but ULFS 49 prevents dysfunction solely by a marked negative chronotropic effect.
Raberger
G
G
Pharmakologisches Institut, Universität Wien, Austria.
Krumpl
G
G
Schneider
W
W
Mayer
N
N
D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D001552:Benzazepines / Q000627:therapeutic use*; D003000:Clonidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D003327:Coronary Disease / Q000188:drug therapy* / Q000209:etiology; D003864:Depression, Chemical; D004285:Dogs; D006339:Heart Rate / Q000187:drug effects*; D009200:Myocardial Contraction / Q000187:drug effects*; D005082:Physical Exertion; D011433:Propranolol / Q000627:therapeutic use
D000889:Anti-Arrhythmia Agents; D001552:Benzazepines; D011433:Propranolol; C022192:alinidine; D003000:Clonidine; C043636:zatebradine