Altered heart rate variability in panic disorder patients.

Resting electrocardiographic recordings were obtained from 10 patients with panic disorder (PD) and 14 normal controls. Signal analysis of the beat-to-beat heart rate variability was performed by means of power spectrum analysis. The analysis revealed that patients with PD had marked reduction in the high-frequency peaks of the power spectrum densities. An Energy Ratio Index (ERI), which accurately differentiated between patients and controls, was calculated. In PD patients, a significant correlation was demonstrated between the clinical ratings and the energy ratios. Our findings suggest that decreased heart rate variability may be a characteristic of PD. The importance of this finding as a diagnostic marker and the underlying pathophysiological mechanisms need to be further explored.