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Ablation vs. Rate Control in AF and Systolic Dysfunction
Study Questions:
Does catheter ablation for atrial fibrillation (AF) improve left ventricular (LV) systolic dysfunction compared to medical rate control?
Methods:
CAMERA-MRI, a multicenter randomized clinical trial, enrolled patients with persistent AF and idiopathic cardiomyopathy (LV ejection fraction [LVEF] ≤45%). After optimization of rate control, patients underwent cardiac magnetic resonance (CMR) imaging to assess LVEF and late gadolinium enhancement, indicative of ventricular fibrosis, before randomization to either catheter ablation or ongoing medical rate control. Catheter ablation included pulmonary vein and posterior wall isolation. AF burden after catheter ablation was assessed by implanted loop recorder, and adequacy of medical rate control by serial Holter monitoring. The primary endpoint was change in LVEF on repeat CMR at 6 months.
Results:
A total of 301 patients were screened; 68 were enrolled and randomized. The average AF burden after catheter ablation was 1.6% ± 5.0% at 6 months. On intention-to-treat analysis, absolute LVEF improved by +18 ± 13% in the catheter ablation group compared to +4.4 ± 13% in the medical rate control group (p < 0.0001), and normalized (LVEF ≥50%) in 58% versus 9% (p = 0.0002). In those undergoing catheter ablation, the absence of late gadolinium enhancement predicted greater improvements in absolute LVEF (+10.7%, p = 0.0069) and normalization at 6 months (73% vs 29%, p = 0.0093).
Conclusions:
In a population of patients with idiopathic cardiomyopathy, restoration of sinus rhythm with catheter ablation results in significant improvements in LV function, particularly in the absence of ventricular fibrosis on CMR.
Perspective:
In patients with cardiomyopathy, prior studies of rhythm control with antiarrhythmic medications had disappointing results. A few studies of catheter ablation in various AF types and cardiomyopathy populations have shown benefits in patients in whom sinus rhythm is maintained after AF ablation. The present study confirms many of those findings in a population of patients with persistent AF and idiopathic cardiomyopathy, especially in patients who do not have late gadolinium enhancement on MRI. The current study supports the notion that rhythm strategy with ablation should be pursued despite the achievement of good rate control. It just so happens that another study, involving patients with paroxysmal and persistent AF, with a greater number of patients, was just presented at the the European Society of Cardiology Congress. CASTLE-AF (Catheter Ablation vs. Conventional Therapy For Patients With AF and LV Dysfunction) showed that the composite of all-cause mortality and hospitalization for worsening heart failure was significantly lower in the ablation group (28.5%) compared to the control group (44.6%) over a median follow-up period of 37.8 months.
Keywords: Anti-Arrhythmia Agents, Arrhythmias, Cardiac, Atrial Fibrillation, Cardiac Imaging Techniques, Cardiomyopathies, Catheter Ablation, Electrocardiography, Ambulatory, ESC Congress, ESC2017, Gadolinium, Heart Failure, Magnetic Resonance Imaging, Primary Prevention, Stroke Volume, Ventricular Dysfunction, Left
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