Electrocardiographic effects of right atrial pacing and nitroglycerin in atherosclerotic rhesus monkeys.

Right atrial pacing at rapid heart rates induced ischemic S-T segment changes in 19 atherosclerotic, male rhesus monkeys. Prior administration of nitroglycerin (100 mug/kg, i.v.) prevented the S-T segment alteration at a given pacing rate in 5 animals, attenuated it in 12 others, and had no effect in the remaining 2. The results of these studies are similar to earlier ones in atherosclerotic rabbits.