BACKGROUND: The electrocardiographic Tpeak-Tend interval is considered a novel risk marker of cardiac arrhythmias and cardiovascular death; however, results to date have been conflicting.

OBJECTIVE: The purpose of this study was to investigate the association between this interval and the risk of all-cause and cardiovascular mortality, atrial fibrillation, and heart failure, allowing for nonlinear relationships.

METHODS: From primary care, 138,404 individuals were included and categorized into seven groups based on Tpeak-Tend interval. Cox regression models were used to describe the association between these groups and the risk of the selected outcomes.

RESULTS: Compared with the reference groups (104-115 ms for all-cause mortality and 98-103 ms for all other outcomes), individuals with a Tpeak-Tend interval in lead V5 <5th percentile (58-77 ms) had hazard ratios of 1.29 (95% confidence interval [CI] 1.21-1.38, P <.001) for all-cause mortality, 1.31 (95% CI 1.15-1.50, P <.001) for cardiovascular death, 1.18 (95% CI 1.06-1.32, P = .003) for atrial fibrillation, and 1.52 (95% CI 1.33-1.74, P <.001) for heart failure. Individuals with a Tpeak-Tend interval ≥95th percentile (116-140 ms) had hazard ratios of 1.15 (95% CI 1.08-1.23, P <.001) for all-cause mortality, 1.30 (95% CI 1.15-1.47, P <.001) for cardiovascular death, 1.09 (95% CI 0.99-1.22, P = .088) for atrial fibrillation, and 1.28 (95% CI 1.12-1.46, P <.001) for heart failure. Similar results were obtained for leads II and V2.

CONCLUSION: We observed U-shaped associations between the Tpeak-Tend interval and risk of all-cause and cardiovascular mortality, atrial fibrillation, and heart failure.