Beat-to-beat heart rate and QT interval variability in first episode neuroleptic-naive psychosis.

Introduction: Though increased risk of sudden death in patients with schizophrenia is well-documented, the mechanisms remain unclear. Recent studies report two known risk factors for sudden cardiac death and other arrhythmias in schizophrenia, i.e., decreased RR interval variability (RRV) and increased QT interval variability (QTV). However, these studies did not control for the effects of medication. Herein, we report the results of our study comparing RRV and QTV in first episode neuroleptic-naive psychosis patients with healthy matched controls.

Methods: 24 patients with first episode neuroleptic naïve psychosis were matched with 26 healthy controls on age and gender. After an overnight fast, all participants underwent an electrocardiogram recording in the morning.

Results: In comparison with matched controls, patients with first episode neuroleptic-naïve psychosis had significantly increased QTV corrected for RRV, and decreased RRV.

Conclusions: The observed alterations in RRV and QTV may reflect impaired cardiac autonomic function that could underlie risk for abnormal ventricular repolarization and thereby increase the risk of sudden death and other arrhythmias. Our data suggest that RRV and QTV alterations may be independent of medication effects in first episode psychosis patients.