Prediction of arrhythmias in primary prevention ICD patients: Resting versus exercise electrocardiogram

Ejection fraction and microvolt T-wave alternans (mTWA) lack specificity to predict sudden cardiac death in heart failure (HF). We compared resting ECG variables (QRS duration, lead-dependent T-amplitudes) and exercise-ECG-derived TWA variables (amplitude in the 12 leads, in the orthogonal X, Y, Z leads and in the vector magnitude) of 56 HF patients with an implanted cardioverter-defibrillator: cases and matched controls with/without antiarrhythmic therapy for VT/VF during follow up. Linear discriminant models, using resting and exercise ECG variables, were built in half of the study group, and were tested on the other half. QRS duration and TWA in lead Z discriminated best in the resting and exercise ECG, respectively, and had comparable diagnostic accuracy for VT/VF prediction.