Predictive value of frontal QRS-T angle after cardiac resynchronization therapy.

OBJECTIVE

It is practical and useful to detect patients who benefit from cardiac resynchronization therapy (CRT) by electrocardiographic (ECG) methods. In this study, the predictive role of the frontal QRS-T angle and other ECG parameters was evaluated in CRT responder patients.

METHOD

Seventy-seven consecutive patients with left ventricular ejection fraction (LVEF) ≤ 35%, New York Heart Association (NYHA) classes II-III, ambulatory class IV and normal sinus rhythm, who had complete left bundle branch block and were treated with CRT were included in this study. Patients were classified as "CRT responders" and "CRT non responders" according to their LVEF improvement. The frontal QRS-T angle was calculated as the absolute value of the difference between the QRS and T wave axes [frontal QRS-T angle = (QRS axis-T axis)].

RESULTS

The mean age of the patients was 64.5 ± 9.1 years, and the average follow-up was 28 (12-47) months. The post-implantation LVEF was higher in the patients CRT responders group (p < 0.001). Post-implantation frontal QRS-T angle (p = 0.003), QRS duration (p = 0.008) and cQT interval (p = 0.012) values were much shorter in the CRT responder group. Multivariable regression analyses showed that the frontal QRS-T angle and age were independent risk factors for CRT response (p = 0.009). The results of the receiver operating characteristic curve analyses (ROC) showed that the predictive optimal cut-off value of CRT response for the frontal QRS-T angle was <135 degrees (AUC: 0.69, 95% CI 0.575-0.814, p = 0.004).

CONCLUSION

The narrowed frontal QRS-T angle (<135 degrees), QRS duration and cQT interval were associated with CRT response in heart failure patients. The frontal QRS-T angle can be an independent predictor of CRT response.