Background: Since there is an uncertainty regarding which of the 12 leads provides the most information, we investigated the association between repolarization phenomenon in all of the 12 leads and cardiovascular (CV) mortality.
Methods: Retrospective cohort study was performed at Palo Alto Veterans Affairs Medical Center, Palo Alto, California, which included 24,270 consecutive male veterans with ECGs obtained for clinical reasons from 1987 to 2000. Analysis of computerized 12-lead resting ECGs was performed of all subjects excluding inpatients, patients with atrial fibrillation, WPW, QRS duration > 120 ms, and paced rhythms. Average follow-up was 7.5 years during which time there were 1859 CV deaths.
Results: While ST segment measurements in aVR were univariately predictive of CV death, T wave amplitude superseded them in multivariate survival analysis. In addition, T wave amplitude in aVR outperformed repolarization measurements in all other leads as well as other ECG criteria (Q waves, damage scores, LVH) for predicting CV mortality. As T wave amplitude became less negative in aVR, there was a progressive increase in relative risk (RR). When the T waves in aVR had a positive deflection (i.e., upward pointing) the RR for CV death was 5.0.
Conclusions: T wave amplitude in lead aVR is a powerful prognostic marker for estimating risk of CV death. Upward pointing T waves (a simple visual criterion) was prevalent (7.3% of a clinical population) and was associated with an annual CV mortality of 3.4% and a risk of five times.