Regression of Ventricular Fibrosis After Catheter Ablation

Study Questions:

Is catheter ablation (CA) of atrial fibrillation (AF) associated with regression of ventricular fibrosis in patients with AF-mediated cardiomyopathy?

Methods:

In this substudy of the CAMERA-MRI trial, 36 patients (mean age 61 years) with persistent AF and nonischemic cardiomyopathy (ejection fraction [EF] ≤45%, mean 34%) were randomly assigned to CA (n = 18) or a rate-control strategy (n = 18). Cardiac magnetic resonance imaging was performed at baseline and 6 months. Ventricular fibrosis was quantified by T1 mapping.

Results:

The mean AF burden in the CA arm was reduced to 0.8% at 6 months of follow-up. At 6 months, compared to baseline, there was a significant reduction in the mean myocardial T1 time in the CA arm (-92 ms), but not in the rate-control arm. Improvement in T1 time was associated with a significant increase in EF (absolute change of +14%) and reduction in serum B-type natriuretic peptide (-213 ng/L). These parameters did not change significantly in the rate-control arm.

Conclusions:

Six months of sinus rhythm after CA in patients with persistent AF and left ventricular dysfunction is sufficient to result in regression of ventricular fibrosis in association with an improvement in left ventricular function.

Perspective:

At some point in the natural history of AF-mediated cardiomyopathy, it is likely that ventricular fibrosis will transition to irreversible scar and permanent remodeling. Although the mean duration of continuous AF was 24 months in the CA arm of this study, the ventricular fibrosis was still reversible. This is an encouraging finding that reinforces the appropriateness of CA even in patients whose AF is long-standing.

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Heart Failure and Cardiac Biomarkers, Magnetic Resonance Imaging

Keywords: Arrhythmias, Cardiac, Atrial Fibrillation, Cardiomyopathies, Catheter Ablation, Fibrosis, Heart Failure, Magnetic Resonance Imaging, Natriuretic Peptide, Brain, Stroke Volume, Ventricular Dysfunction, Left, Ventricular Function, Left


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