Frontal QRS-T Angle and the Risk of Atrial Fibrillation in the Elderly

Abstract

Background Frontal QRS-T angle reflects changes in regional action potential duration and the direction of repolarization. Although it has been suggested that abnormal ventricular repolarization predisposes to atrial arrhythmias, it is unknown whether abnormal frontal QRS-T angle is associated with an increased risk of atrial fibrillation (AF). Methods We examined the association between frontal QRS-T angle and AF in 4,282 participants (95% white; 41% male) from the Cardiovascular Health Study (CHS). QRS-T angle was computed from baseline electrocardiogram data. Abnormal QRS-T angle was defined as values greater than the sex-specific 95th percentile (men >131°; women: >104°). AF cases were identified from study electrocardiograms and from hospitalization discharge data through December 31, 2010. Cox regression was used to compute hazard ratios (HR) and 95% confidence intervals (CI) for the association between abnormal QRS-T angle and AF. Results Over a median follow-up of 12.1 years, a total of 1,276 (30%) participants developed AF. In a Cox regression model, adjusted for socio-demographics and known AF risk factors, abnormal QRS-T angle was associated with a 55% increased risk of AF (HR=1.55, 95%CI=1.23, 1.97). When QRS-T angle was examined as a continuous variable, each 10° increase was associated with a 3% increased risk of AF (HR=1.03, 95%CI=1.01, 1.05). This finding was consistent in subgroups stratified by age, sex, and race. Conclusion Our findings suggest that an abnormal frontal QRS-T angle on the electrocardiogram provides important prognostic information regarding AF risk in the elderly, and further implicate ventricular repolarization abnormalities in the pathogenesis of AF.

Frontal plane QRS‐T angle in the monitoring of intravenous amiodarone infusion for pharmacological cardioversion of acute atrial fibrillation

“…22,23 However, no study has investigated the impact of antiarrhythmic drugs on frontal plane QRS-T angle. Because increase in frontal plane QRS-T angle predicts arrhythmia and arrhythmic death, 9,12 it is reasonable to investigate the impact of antiarrhythmic drugs on frontal plane QRS-T angle.…”

“…[9][10][11] Importantly, increased frontal plane QRS-T angle seems to be associated with an increased risk for Af development independent of well-known Af risk factors. 12 However, no study has investigated the importance and usefulness of frontal plane QRS-T angle in patients with a recent-onset Af episode. Moreover, although amiodarone can cause various changes in electrocardiography (ECG), the impact of intravenous amiodarone infusion on frontal plane QRS-T angle has not been demonstrated yet.…”

The role of baseline and post‐procedural frontal plane QRS‐T angles for cardiac risk assessment in patients with acute STEMI

“…The f(QRS‐T) angle was calculated from these axes as absolute difference between frontal plane QRS axis and frontal plane T axis. If the angle exceeds 180°, it was calculated by subtracting from 360 o (Jogu et al., ; Macfarlane, ; Oehler et al., ; Zhang et al., ). Because our calculation of f(QRS‐T) angle was based on automatic report of ECG machine, the subjective component of the individual measurements have been eliminated.…”

Electrocardiographic QRS-T angle and the risk of incident silent myocardial infarction in the Atherosclerosis Risk in Communities study

“…The QRS/T angle is a sensitive and reproducible marker of abnormal ventricular depolarization and repolarization which is able to detect depolarization and repolarization abnormalities before other common markers are apparent as QRS duration or QT interval [13–16]. Abnormal ventricular repolarization is an established mechanism for arrhythmogenesis.…”

“…A decade ago, we first reported that the frontal plane QRS/T angle was a ‘suitable clinical substitute’ for spatial QRS/T angle with respect to CHD risk prediction in the ARIC study [12]. Since then, the frontal QRS/T angle has been intensively studied in various populations, as a predictor of different outcomes including heart failure, atrial fibrillation, sudden cardiac death, and all-cause mortality [16–18,24–26]. Our study adds SMI to this list of outcomes, for the first time.…”