Catheter Ablation Versus Medical Rate Control in Atrial Fibrillation and Systolic Dysfunction The CAMERA-MRI Study

Sandeep Prabhu, Andrew J. Taylor, Ben T. Costello, David M. Kaye, Alex J.A. McLellan, Aleksandr Voskoboinik, Hariharan Sugumar, Siobhan M. Lockwood, Michael B. Stokes, Bhupesh Pathik, Chrishan J. Nalliah, Geoff R. Wong, Sonia M. Azzopardi, Sarah J. Gutman, Geoffrey Lee, Jamie Layland, Justin A. Mariani, Liang-han Ling, Jonathan M. Kalman, Peter M. Kistler

Atrial fibrillation (AF) and left ventricular systolic dysfunction (LVSD) frequently co-exist despite adequate rate-control. Existing randomized studies of AF and LVSD of varying etiologies have demonstrated modest benefits with a rhythm control strategy. To determine whether catheter ablation (CA) for AF could improve LVSD compared to medical rate-control (MRC) where the etiology of the LVSD was unexplained, apart from the presence of AF. This multi-center randomized clinical trial enrolled patients with persistent AF and idiopathic cardiomyopathy (LVEF ≤45%). After optimization of rate-control, patients underwent cardiac MR (CMR) to assess LVEF and late gadolinium enhancement (LGE), indicative of ventricular fibrosis, before randomization to either CA or ongoing MRC. CA included PVI and posterior wall isolation. AF burden post CA was assessed by implanted loop recorder, and adequacy of MRC by serial Holter-monitoring. The primary endpoint was ΔLVEF on repeat CMR at 6 months. 301 patients were screened and 68 enrolled between November 2013 and October 2016 and randomized with 33 in each arm accounting for two dropouts. The average AF burden post CA was 1.6% ± 5.0% at six months. On intention to treat analysis, absolute LVEF improved by +18 ± 13% in the CA group compared to +4.4 ± 13% in MRC group, (p <0.0001) and normalized (LVEF ≥50%) in 58% vs 9%, p = 0.0002. In those undergoing CA, the absence of LGE predicted greater improvements in absolute LVEF (+10.7%, p = 0.0069) and normalization at 6 months (73% vs 29%, p = 0.0093). AF is an underappreciated reversible cause of LVSD in this population despite adequate rate control. The restoration of sinus rhythm with CA results in significant improvements in ventricular function, particularly in the absence of ventricular fibrosis on CMR. This challenges the current treatment paradigm that rate control is the appropriate strategy in patients with AF and LVSD.