Background: Repolarization abnormalities are associated with ventricular arrhythmias, and published studies report that a reversal of T wave polarity (positive or flat T wave) in lead aVR may be linked to increased cardiovascular mortality. We evaluated whether a positive or flat T wave in aVR is a risk marker for sudden cardiac death (SCD).
Methods: SCD cases from the Oregon Sudden Unexpected Death Study (catchment population ~1 million) were compared to geographic controls with coronary artery disease and no history of SCD. Archived electrocardiograms performed prior and unrelated to the SCD event were evaluated.
Results: SCD cases (n = 691, 67.6 ± 14.9 years, 69% male) were more likely than controls (n = 663, 66.2 ± 11.6 years, 67% male) to have diabetes (40 vs 32%; p < 0.01), left ventricular ejection fraction (LVEF) ≤35% (27 vs 11 %; p < 0.01), prolonged QTc (≥450 ms; 54 vs 28%; p < 0.01) and positive (19 vs 13%; p < 0.01) or flat T wave (14 vs 7%; p < 0.01) in aVR. On multivariable analysis, a positive/flat T wave in aVR was independently associated with SCD (OR 1.9, 95% CI 1.3-2.8, p < 0.01). However, a positive T wave alone lost statistical significance in patients with LVEF ≤ 35% and QTc ≥ 450 ms. In a subgroup analysis among patients with normal LVEF, QTc, and no diabetes, a positive T wave in aVR (but not a flat T wave) remained associated with SCD (OR 2.8, 95% CI 1.2-6.1, p < 0.01).
Conclusions: A positive or flat T wave in lead aVR was associated with SCD in subsets of patients. This simple ECG marker in this often-ignored lead may contribute to enhancement of SCD risk stratification, and warrants further evaluation.
Keywords: Electrocardiography; Lead aVR; Risk stratification; Sudden cardiac death.