Effects of changing heart rate on electrophysiological and hemodynamic function in the dog.

摘要: Abstract Cardiovascular parameters were measured in dogs after RR interval was changed from 0.25 s to 1.2 with atropine and graded doses of zatebradine, an I f -channel blocker. Left ventricular (LV) pre-ejection period (PEP), systemic vascular resistance, tau (an estimate myocardial stiffness), PQ, QTc, dLVP/dt max min , aortic pressure, right atrial pressure did not change when each parameter plotted against (r 2 's ≤ 0.5). LV end-diastolic stroke volume index, ejection time (ET), QT all increased either linearly or curvilinearly as prolonged. Cardiac output index PEP/ET decreased curvilinearly. When heart rate (HR) fixed by pacing, zatebradine given, changes cardiovascular function minimal. Thus affects principally changing HR affecting directly. This study provides data on the effects HR, alone, frequently during pharmacological toxicological studies. It should prove useful physiological variables, including change, there is need know what contributes.