Myocardial dyssynchrony assessed by CMR-TSI is a powerful independent predictor of mortality and morbidity after CRT.

A PL scar is associated with a worse clinical outcome following CRT, particularly if it is transmural. Pacing scarred left ventricular myocardium carries a greater risk of mortality and morbidity than pacing nonscarred myocardium.

Cardiac resynchronisation therapy leads to similar prognostic and symptomatic benefits in patients in AF and SR, even without atrioventricular junction ablation. Echocardiographic improvements are also comparable.