The effect of tricyclic antidepressants on stress-induced heart rate changes in panic disorder patients.

Eight panic disorder patients participated in a double-blind placebo-controlled infusion study designed to induce panic-anxiety in the laboratory both before and after treatment with tricyclic antidepressants. Pre-infusion heart rates for the first infusion were significantly higher than baseline both before and after treatment. The delta increase in pre-infusion heart rates from baseline and the ratios of pre-infusion heart rates to baseline values were not significantly different between before and after treatment conditions indicating similar levels of arousal during the two pre-infusion periods, while the pre-infusion anxiety ratings after treatment were significantly lower.