Association of PR Interval with Illness Duration and Lymphocyte Count in Asian Adults with Bipolar Disorder

Abstract

Objective: Individuals with serious mental illness are predisposed to a heightened risk of cardiac arrhythmias, with specific subtypes demonstrating a disproportionately high prevalence in Asian populations.An overlapping pathophysiology is hypothesized to underpin this clinical association.This study investigated the association between electrocardiographic (ECG) parameters and the clinical characteristics of Asian adults with bipolar disorder (BD).Methods: This multicenter retrospective study analyzed data of 230 patients with BD admitted to Taipei Medical University-affiliated teaching hospitals between 2006 and 2015.Clinical characteristics and ECG parameters in the index (final) psychiatric hospitalization were extracted from medical records and reviewed by experienced, board-certified psychiatrists and a cardiologist.Results: The study sample comprised patients with the median age of 61.0 years at the index psychiatric hospitalization and the median BD duration of 30.0 years.Approximately one-third of the participants were male.The median ECG PR interval at index hospitalization was 158.0 milliseconds.Correlation analysis revealed that BD duration was positively correlated with the PR interval.Additionally, marginal correlations were found between the PR interval and serum uric acid levels, blood lymphocyte counts, and the neutrophil-to-lymphocyte ratio.Multiple regression analysis revealed that both the duration of BD illness (p = 0.042) and blood lymphocyte count (p = 0.032) were significantly associated with the PR interval duration.Conclusion: This study provides preliminary evidence linking the pathophysiology of BD to PR interval variations.Future longitudinal research is warranted to validate these findings and elucidate the underlying mechanisms.