Difference in QRS Variability According to Clinical Outcome in Severe Heart Failure Patients

Abstract

Background: QRS duration is well known predictor for survival in heart failure patients. We investigated whether there is any difference in variation of QRS duration according to clinical outcome.
Method: Total 457 patients (60±14 ages, 62% men) with severe left ventricular dysfunction (left ventricular ejection fraction (LVEF) ≤35%) were enrolled. We calculated QRS variability by difference between baseline and maximum QRS duration during follow-up (53±18 months).
Result: The average QRS duration at baseline, at maximum and QRS variability were 111±27 [64~0272], 124±32 [72~0272] and 12±19 [0~0164] ms, respectively. Survival group (n=346) showed shorter QRS duration both at baseline (109 vs. 117 ms, p=0.008) and at maximum (120 vs. 134 ms, p=0.02) than decreased group (n=111). QRS variability was lower in survival group (11 vs. 17 ms, p=0.02). Patients who showed LVEF improvement (>5% compared to baseline LVEF, n=277) showed shorter QRS duration both at baseline (106 vs. 118 ms, p<0.001) and at maximum (117 vs. 132 ms, p<0.001) and QRS variability (10 vs. 15 ms, p=0.04) than those who did not.
Conclusion: In severe heart failure patients, survival group and those with LV systolic improvement showed shorter QRS duration and variation during follow-up. The variation of QRS duration analyzed by serial ECG follow-up might give additional prognostic information to QRS itself in severe heart failure patients.