Should different ECG QRS duration criteria be used for men and women with heart failure for cardiac resynchronization therapy?

In the present paper we review data of the efficacy of CRT based on baseline QRS duration and morphology in patients with heart failure due to left ventricle systolic dysfunction. We specifically review data that analyzed men and women separately. The main findings suggest benefit of CRT in patients with baseline LBBB, but not in patients without LBBB. Benefit is directly related to QRS duration at baseline with increasing rates and magnitude of echocardiographic response (in terms of improvement in ejection fraction and decrease in LV size) and clinical response with increasing baseline QRS. The effect was most pronounced when QRSd was above 150 ms. Among women treated with CRT, similar to men, the benefit is also confined mainly to patients with baseline LBBB. In contrast to men benefit is evident starting with QRSd >130 ms. These findings may suggest that different QRS duration criteria should be used for men and women considered for CRT.