Predictors of non-response to cardiac resynchronization therapy implantation in patients with class I indications: the markedly dilated left ventricular end-diastolic dimension and the presence of fragmented QRS

Background Cardiac resynchronization therapy (CRT) is a highly effective treatment in patients with a class I recommendation. However, a small proportion of the strictly selected patients still fail to respond. This study was designed to identify predictors of non-response in patients with class I indications for CRT and determine the non-response probability of the patients. Methods A total of 296 consecutive patients with a class I recommendation received CRT from January 2009 to January 2017 were retrospectively analyzed. Multivariate logistic regression analysis was performed to identify predictors for non-response (defined as cardiac death, heart transplantation, or HF hospitalization during 1-year follow-up). Results Among 296 patients, 30 (10.1%) met non-response. Multivariate analysis demonstrated that non-response to CRT was associated with a fragmented QRS (odd ratio (OR) = 2.86, 95% CI: 1.14–7.12; P = 0.025) and left ventricular end-diastolic dimension (LVEDD) ≥ 77 mm (OR = 3.02, 95% CI: 1.17–7.82; P = 0.022). Patients with both of the predictors had a non-response probability of 46.2% (95% CI: 19.1%–73.3%). Conclusion In patients with left bundle branch block and wider QRS duration, the proportion of non-response to CRT is not low in real world. The presence of the dilated LVEDD or fragmented QRS is a strong predictor of non-response to CRT. The probability of non-response in the patients with the two predictors was 46.2%.