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

Abstract

Introduction-Though increased risk of sudden death in patients with schizophrenia is welldocumented, the mechanisms remain unclear. Recent studies report two known risk factors for sudden cardiac death and other arrhythmias in schizophrenia, i.e., decreased R-R 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.

QTc interval and its variability in patients with schizophrenia and healthy subjects: implications for a thorough QT study

“…It must be noted that the within-subject variability in the present study pertains to changes in QTc intervals over a period of days or weeks (Bexton et al 1986), and should not be confused with beat-to-beat QT variability which assesses variability in QTc interval in a series of consecutive beats recorded over a relatively shorter period of hours or minutes (Bär et al 2007 ;Jindal et al 2009). Beat-to-beat QT variability analysis is used to study the effects of autonomic influences on cardiac repolarization using complex mathematical and computational methods (Bär et al 2007 ;Jindal et al 2009) and decreased beat-to-beat variability has been associated with increased risk of cardiac arrhythmias and sudden death in a variety of cardiac conditions (Berger et al 1997 ;Myredal et al 2008).…”

Autonomic nervous system dysfunction in psychiatric disorders and the impact of psychotropic medications: a systematic review and meta-analysis

“…224,225 A more important question for future research may be what impact age and earlier manifestions of the disorder have on changes in HRV over time, including first-episode and prodromal periods, as symptoms change or worsen. 65,226,227 Additionally, the inclusion of cross-sectional studies in the case-control analysis does not address the question of whether reduced vagal control in these populations is part of a potential mechanism placing these individuals at a greater risk for cardiovascular disease, or whether reduced HRV in these groups compared to controls is actually a downstream effect of altered neural pathways that control autonomic regulation of the heart. 228 Our search strategy included other classes of psychotropic medications (e.g., mood stabilizers, benzodiazepines) and …”

Relation between Beat‐to‐Beat QT Interval Variability and T‐Wave Amplitude in Healthy Subjects

“…6 In addition, elevated beat-tobeat QTV has also been demonstrated in patients with obstructive sleep apnea 7 and mental disorders. 8 However, the mechanisms underlying QTV are incompletely understood. Reduction in repolarisation reserve has been suggested to increase QTV.…”