Several retrospective single centre studies in highly selected patients have demonstrated marked improvements in left ventricular (LV) function in patients undergoing successful catheter ablation for atrial fibrillation (AF). However, in this patient population the success of catheter ablation is modest with multiple procedures common and a not insignificant risk of serious complications. The contribution of AF to LV function is likely variable as highlighted in more recent randomised studies which have observed a more modest improvement in left ventricular ejection fraction (LVEF).
Therefore, there is a need for a non-invasive tool such as cardiac MRI that will assist in evaluating patients with heart failure where AF is contributing significantly to LV dysfunction and in whom catheter ablation should be considered. We have commenced a multicentre randomised control trial in patients with AF and unexplained heart failure to compare rhythm control by catheter ablation with conventional rate control drug therapy for patients with or without ventricular fibrosis. Ventricular fibrosis will be identified by cardiac MRI screening on the basis of late gadolinium enhancement (LGE).
The aim of this project is to improve the treatment of AF in heart failure; specifically, to target patients for catheter ablation who will gain the most benefit from this procedure. In addition, patients with cardiac ejection fraction less than 35 per cent would routinely be implanted with a defibrillator which would be avoided if cardiac function recovers with successful AF ablation.