Abstract 10009: Post-Implant QRS Narrowing: A Simple and Strong Predictor of the Long-Term Outcome After Receiving Cardiac Resynchronization Therapy
Background: In heart failure (HF) patients, a wider QRS may indicate ventricular dyssynchrony, and QRS narrowing after receiving cardiac resynchronization therapy (CRT) may predict a favorable outcome. However, there is little information on the relationship between the paced-QRS width or change in the QRS width and the outcome after CRT.
Methods: This study included 112 HF patients who received CRT (NYHA class: II/III/IV=18/70/24; 63±17 years; Ischemic=26). ECGs from pre- and post-implantation were analyzed. The primary endpoint was a composite of death or HF hospitalization.
Results: During an 18 month post-CRT study period, 56 (50%) patients reached the primary endpoint (Event(+) group), but the remaining 56 (Event(-) group) did not. No significant difference was found in the age, gender, structural heart disease, echocardiographic parameters or post-implant QRS width between the 2 groups. However, the baseline NYHA class grade (p<0.001) was greater, and the baseline QRS width (p<0.01) and post-implant QRS narrowing (p<0.001) were smaller in the Event(+) group than Event(-) group. By a receiver operator characteristic analysis, a post-implant QRS of <15 msec was the threshold value for the primary endpoint with a 68 % sensitivity and 75 % specificity (area under the curve: 0.72, p<0.001). The event-free rate was greater in patients with a QRS narrowing of ≥15 msec than in those without (p<0.001; Figure). The Cox regression analysis revealed that a QRS-narrowing of <15 msec was an independent predictor of an unfavorable, long-term outcome (Hazard ratio [HR]=3.454; 95% confidence interval [CI]=1.648-7.238, p=0.001) as well as the baseline NYHA class (HR=2.396, 95% CI=1.543-3.720, p<0.001). However, the baseline or post-implant QRS width was not associated with the long-term outcome.
Conclusion: The presence or absence of post-implant QRS narrowing, not the baseline or post-implant QRS width itself, could predict the long-term outcome after receiving CRT.
- © 2011 by American Heart Association, Inc.