Association Between QT-Interval Components and Sudden Cardiac Death

Abstract

Background Several reports have demonstrated that prolongation of the QT interval is associated with sudden cardiac death (SCD). However, it is unknown whether any of the components within the QT interval are responsible for its association with SCD. Methods and Results We examined the association of the individual QT interval components (R-wave onset to R-peak, R-peak to R-wave end, ST-segment, T-wave onset to T-peak, and T-peak to T-wave end) with SCD in 12,241 participants (54 ± 5.7 years; 26% black; 55% women) from the Atherosclerosis Risk In Communities (ARIC) study. The QT interval and its components were measured at baseline (1987-1989) from 12-lead electrocardiograms. SCD cases were adjudicated by a group of physicians through December 31, 2012. Over a median follow-up of 23.6 years, a total of 346 cases of SCD were identified. While prolongation of the QT interval was associated with a 49% increased risk of SCD (HR=1.49, 95%CI=1.01, 2.18), only the T-wave onset to T-peak component (per 1-SD increase: HR=1.19, 95%CI=1.06, 1.34) was associated with SCD, and not any of the other components in separate models. When all of the QT interval components were included in the same model, T-wave onset to T-peak remained the strongest predictor of SCD (per 1-SD increase: HR=1.21, 95%CI=1.06, 1.37). Conclusion The risk of SCD with the QT interval is driven by prolongation of the T-wave onset to T-peak component. This suggests that shifting the focus from the overall QT interval to its individual components will refine SCD prediction in the community.

Associations between QT interval subcomponents, HIV serostatus, and inflammation

“…to T-peak is associated with increased SCD risk and incident atrial fibrillation in community-based cohorts without prevalent cardiovascular disease (O'Neal et al, 2017;Roberts et al, 2017). We find here a distinctive positive association between HIV infection and both T-wave components.…”

“…Prior studies have reported the association between longer T‐peak to T‐end and increased risk for SCD in cohorts with pre‐existing heart disease (Goldenberg & Moss, ; Morin et al, ; Panikkath et al, ; Rosenthal et al, ; Shimizu et al, ; Yamaguchi et al, ). In contrast, prolonged T‐onset to T‐peak is associated with increased SCD risk and incident atrial fibrillation in community‐based cohorts without prevalent cardiovascular disease (O'Neal et al, ; Roberts et al, ). We find here a distinctive positive association between HIV infection and both T‐wave components.…”

“…Tracings were excluded ( n = 137) from analysis because of poor quality ( n = 32), nonsinus rhythm (e.g., atrial fibrillation/flutter, n = 15 or paced atrial rhythm, n = 5), or major intraventricular conduction defects (QRS duration ≥120 ms, Wolff–Parkinson–White syndrome, or ventricular pacemaker, n = 85). Left ventricular hypertrophy (LVH) was defined by the Cornell criteria (O'Neal et al, ).…”

“…The second subcomponent, the JT interval, is a purer measure of myocardial repolarization and includes three segments: the ST segment and two T‐wave subcomponents, T‐wave onset to T‐wave peak, and T‐wave peak to T‐wave end. Longer T‐wave subcomponents have been associated with atrial and ventricular arrhythmias and SCD in HIV‐uninfected (HIV−) cohorts (Goldenberg & Moss, ; Morin et al, ; O'Neal et al, ; Panikkath et al, ; Roberts et al, ; Rosenthal et al, ; Shimizu et al, ; Yamaguchi et al, ). Whether these associations occur in HIV‐infected (HIV+) persons is unknown.…”

Importance of the heart vector origin point definition for an ECG analysis: The Atherosclerosis Risk in Communities (ARIC) study

“…To identify cases of SCD in ARIC, cases of cardiovascular death that occurred by December 31, 2012, were reviewed and adjudicated by a committee of electrophysiologists, general cardiologists, and internists, as previously described. [13]…”