Effect of quinidine on the heart rate and blood pressure response to treadmill exercise

The effect of quinidine on the heart rate and blood pressure response to treadmill exercise was evaluated in 17 normal subjects. Quinidine significantly increased the heart rate at rest and at low levels of exercise. Quinidine had no significant effect on the systolic blood pressure response to any work load. However, quinidine significantly decreased the systolic blood pressure at all exercising heart rates, compared to control, in 15 of the 17 subjects. The magnitude of the decrease in systolic pressure ranged from 1 to 22 mm Hg, with a mean of 10 mm Hg.