Superior diagnostic performance of beat-to-beat T-wave angle monitoring for ventricular arrhythmia prediction during cardiac rehabilitation

Background / Introduction

Risk stratification for ventricular arrhythmias in ischemic heart disease (IHD) traditionally relies on left ventricular ejection fraction (LVEF) and exercise-derived variables such as blood pressure response, Duke treadmill score, Veterans score, and rate–pressure product. However, these static parameters may not adequately capture beat-to-beat electrical instability. Dynamic T-wave angle variation, reflecting periodic repolarization instability, may provide superior predictive value.

Purpose

To determine whether dynamic T-wave angle variation during cardiac rehabilitation is superior to conventional pre-rehabilitation risk markers in predicting ventricular arrhythmias.

Methods

We conducted a prospective cohort study including 78 patients with IHD (31 women). LVEF was <35% in 27 patients, 35–49% in 15, and >50% in the remainder. Fifty-two underwent percutaneous coronary intervention and the rest coronary bypass surgery, with no difference in arrhythmic outcomes between revascularization strategies.

All patients completed a 12-session cardiac rehabilitation program with continuous 12-lead telemetry. Beat-to-beat T-wave angle was analyzed in real time. A sudden change >10° was predefined as abnormal.

The primary endpoint was ventricular arrhythmias (paired premature ventricular complexes, ventricular bigeminy, or non-sustained ventricular tachycardia). Predictive performance was assessed using sensitivity, specificity, positive and negative predictive values, and comparative diagnostic accuracy analysis. Between-method comparisons were performed using chi-square testing, with p<0.05 considered significant.

Results

A T-wave angle change >10° predicted ventricular arrhythmias with sensitivity 89% and specificity 96% (p<0.001 vs no angle change).

False-negative cases were attributable to supraventricular arrhythmias (17 atrial tachycardia, 4 atrial flutter), in which T-wave angle variation was not statistically significant.

Among conventional predictors, only LVEF <35% (sensitivity 77%, specificity 94%; p=0.01) and exercise-induced hypotension (sensitivity 78%, specificity 97%; p=0.008) were significant, but both showed lower sensitivity compared with T-wave angle variation (p<0.05 for sensitivity comparison).

Other markers demonstrated inferior diagnostic performance: Duke score (44%/86%), Veterans score (47%/89%), flat and hypertensive blood pressure responses (28%/74% and 35%/68%), and rate–pressure product (56%/87%), none reaching comparable discriminative capacity.

Conclusion(s)

Dynamic T-wave angle variation >10° during supervised cardiac rehabilitation showed superior sensitivity and high specificity for predicting ventricular arrhythmias compared with conventional pre-rehabilitation risk markers.

Beat-to-beat repolarization monitoring may enhance electrical risk detection beyond traditional stratification strategies in patients with ischemic heart disease.Comparative ROC CurvesForest Plot – Diagnostic Accuracy