Prognostic Implications of QRS Duration in Third-Degree Atrioventricular Block Patients with Heart Failure Treated with Cardiac Resynchronization Therapy.

Cardiac resynchronization therapy (CRT) improves heart function and prognosis in third-degree atrioventricular block (AVB) patients with heart failure (HF). However, it is still unclear how to screen for appropriate patients before implantation. This study aimed to evaluate the value of using QRS duration to predict CRT efficacy.This study enrolled a total of 72 third-degree AVB patients with HF who received CRT implantation. The patients were divided into Groups A (QRS duration < 120 ms, 33 cases), B (120 ms ≤ QRS duration < 150 ms, 22 cases), and C (QRS duration ≥ 150 ms, 17 cases) according to their baseline QRS duration. The effects of different QRS durations on CRT efficacy were analyzed.The CRT response rate were 30.3%, 50.0%, and 76.5% in Groups A, B, and C, respectively (P = 0.008). The patients in the 3 groups showed significant changes in left ventricular (LV) end-diastolic volume, LV end-systolic volume, and LV ejection fraction over the baseline values at 12 months after the implantation (P < 0.05), with the greatest change observed in Group C. Survival analysis indicated statistically significant differences among Groups A, B, and C (P = 0.024). Multivariate logistic regression analysis suggested that QRS duration was an independent prognostic factor for CRT efficacy. Baseline QRS duration was associated with improved myocardial remodeling and reductions in the incidence rates of primary endpoint events.QRS ≥ 150 ms is an effective predictor of postoperative outcome in patients with third-degree AVB and HF treated with CRT.