Analysis of 24-Hour Heart Rate Variability among Panic Disorder Patients without Previous Drug Treatment and Comorbid Disorders

Objective: One of the methods used to assess autonomic nervous system dysfunction in the etiology of panic disorder (PD) is heart rate variability (HRV). HRV is controlled by the sympathetic and parasympathetic (vagal) branches of the autonomic nervous system and reflects the capacity of autonomic stimulation by the parasympathetic system. The aim of this study was to evaluate heart rate variability (HRV) time domain parameters based on twenty four hour holter ECG analysis among drug-naive patients with panic disorder (PD) without any other medical and psychiatric comorbidity. Method: The study group consisted of 41 patients with PD and 46 healthy controls. Participants were evaluated with SCID-1 for psychiatric diagnoses. Then Hamilton Depression Rating Scale (HDRS), Hamilton Anxiety Rating Scale (HARS), Panic Disorder Severity Scale (PDSS) and Clinical Global Impression Scale (CGI-S) were applied to participants. Twenty four hour Holter ECG outcomes were analyzed on a computer program and time domain parameters were evaluated. Results: Among the parameters analyzed from HRV, SDANN was significantly higher (p <0.001); duration of RMSSD, NN50 and pNN50 were lower in PD group than the control group (p = 0.003, p = 0.005, p = 0.047, respectively). In the correlation analysis, there was a moderate negative correlation between CGI-S and NN50 and pNN50. In logistic regression analysis, the increase in SDNN was found to increase the probability of PD by 1.11 (95% CI, 1.010-1.209); the increase in SDANN was found to decrease the probability of PD by 0.892 (95% CI, 0.818-0.973), and the increase in pNN50 was found to decrease the probability of PD by 0.523 (95% CI, 0.342-0.801). Conclusion: The data obtained in our study confirm that there is a decrease in some HRV parameters like RMSSD, NN50 and pNN50 reflecting parasympathetic activity among patients with PD.