EFFECTS OF ISOPROTERENOL INFUSIONS ON HEART-RATE-VARIABILITY IN PATIENTS WITH PANIC DISORDER

Some evidence suggests that patients with panic disorder have a decrea sed cardiac vagal and a relatively higher sympathetic activity. In thi s study, spectral analysis of the time series of heart rate before and after isoproterenol infusions was used to study heart rate variabilit y in six panic disorder patients and 11 normal control subjects. These preliminary data reveal a significant increase of sympathovagal ratio s only in the patient group after isoproterenol administration. The fi ndings suggest a relative increase in cardiac sympathetic and a relati ve decrease in cardiac vagal function in patients with panic disorder during isoproterenol infusions.