Abstract
A system for experimental studies of pacing rate and optimum AV interval in rate responsive dual chamber pacing have been developed and two types of preliminary experiments have been performed on 4 mongrel dogs. The methods are as follows. 1) The system was programmed as a dual chamber pacemaker with a fixed rate, and the cardiac output and right atrial pressures were measured while AV interval was varyed. 2) The system was programmed as a rate res-ponsive pacemaker using a right atrial blood temperature as a guide parameter. Cardiac output and right atrial pressures in the canines in feverish condition were measured varying the AV interval. All experi-ments were performed under anesthesia. Maxmum cardiac output and minimum right atrial pressurs were obser-ved at AV intervals of 100-125ms both at rest and during feverish condition with higher rates. It can be considered that optimum AV intervals during feverish condition with higher rates are not very different from those at rest.
