Prolonged QTc interval is associated with high CHADS2/CHA2DS2-VASc scores and indicates prior stroke among atrial fibrillation patients

Abstract

Background: Prolonged QTc is associated with an increased risk of stroke or early onset atrial fibrillation (AF) in the general population. We hypothesized that a prolonged QTc is independently associated with the risk scores and prevalence of strokes in AF patients.Methods and results: Among 1,154 patients (75.4% male, 57.2 ± 11.1 years old, 68.4% with paroxysmal AF) included in the Yonsei AF ablation Cohort, we analyzed 823 pre-ablation sinus rhythm electrocardiograms. Patients who took amiodarone were excluded. We compared the QTc with the clinical parameters including the CHADS2/CHA2DS2-VASc scores and imaging parameters. Among the patients with prolonged QTc (≥460 ms in women, ≥450 ms in men), the CHADS2/CHA2DS2-VASc scores (both, P < 0.001) were higher, and the proportions of female, heart failure, and persistent AF were significantly higher compared with those in patients with a normal QTc. In a multivariate linear regression analysis, the QTc (regression coefficient 0.003, 95% confidence interval, 0.000？0.006, P = 0.033), LA dimension (regression coefficient 0.022, 95% confidence interval, 0.007？0.037), and E/Em (regression coefficient 0.054, 95% confidence interval, 0.034？0.074) were independently associated with the CHADS2 score. The same parameters including the QTc (regression coefficient 0.006, 95% confidence interval, 0.002？0.010, P = 0.001) were consistently related to the CHA2DS2-VASc score. The QTc was independently associated with a stroke (Odds ratio 1.011, 95% confidence interval, 1.002？1.019, P = 0.019).Conclusions: A prolonged QTc interval is independently associated with the CHADS2/CHA2DS2-VASc scores and prior strokes among AF patients.