The Association of Depression With QT Duration: A Comparison Between Individuals Younger or Older Than 65 Years

OBJECTIVE: The electrocardiogram-derived corrected QT (QTc) interval is an indicator of cardiac autonomic activity that has been proposed as a biological measure to investigate the interplay between depression and cardiovascular diseases. This study assesses whether depression is associated with a longer QTc interval across age groups. METHODS: Assessment of depressive symptoms was performed in 1637 participants of the cross-sectional Corinthia study with the Zung Self-Rating Depression Scale in those younger than 65 years (group 1) and with the Geriatric Depression Scale in elderly individuals (≥65 years, group 2). The QT interval was obtained from electrocardiogram recordings and corrected for heart rate (QTc). RESULTS: Individuals in group 1 with depression were predominantly women and had a higher prevalence of coronary artery disease and diabetes mellitus. Group 1 individuals with depression had longer QTc duration (no depression versus depression, 389.3 [27.0] versus 401.1 [32.9] milliseconds; p < .001) and percentage of abnormal QTc (no depression versus depression, 2.0% versus 10.8%; p = .001) compared with those without depression. Elderly individuals (group 2) had similar values of QTc and percentage of abnormal QTc irrespective of depression status. Even after adjustment for known QT-prolonging factors, the presence of depression in younger individuals was associated with an increased QTc by 11.1 milliseconds and with an approximately 10.6-fold higher prevalence of abnormal QTc duration. CONCLUSIONS: Depression was associated with a longer QTc interval especially in individuals younger than 65 years. These findings may indicate an interrelationship between depression and autonomic dysregulation as potential risk factors for cardiovascular disease and sudden cardiac death.