CMR Detected Atrial Structural and Functional Remodeling in AF HFrEF: Ablation vs Medical Rate Control.

Area of Science:

• Cardiology
• Electrophysiology
• Heart Failure Research

Background:

• Atrial remodeling is a significant issue in heart failure with reduced ejection fraction (HFrEF) and atrial fibrillation (AF).
• The comparative effects of catheter ablation (CA) versus medical rate control (MRC) on atrial function and exercise capacity in these patients remain underexplored.

Purpose of the Study:

• To evaluate changes in biatrial parameters and exercise capacity using cardiac magnetic resonance (CMR) and 6-minute walk tests (6MWT).
• To compare the outcomes of CA versus MRC in patients with AF and HFrEF.

Main Methods:

• Serial CMR assessments of biatrial parameters (atrial ejection fraction [EF], indexed volumes) at baseline and follow-up (≥6 months).
• Serial 6-minute walk tests (6MWT) to assess exercise capacity.
• Analysis of data from the CAMERA-MRI and CAMERA-MRI II multicenter studies.

Main Results:

• Catheter ablation (CA) patients demonstrated significant reverse remodeling of biatrial structure and function (P < 0.001), unlike MRC patients.
• Increased left atrial emptying fraction (LAEF) and reduced AF burden were independently associated with improved left ventricular ejection fraction (LVEF).
• Exercise capacity (6MWT) improved significantly more in CA patients (76.8%) compared to MRC patients (48.8%) (P = 0.002).

Conclusions:

• Restoration of sinus rhythm via CA led to improved biatrial EF and reverse remodeling compared to MRC.
• Atrial fibrillation (AF) burden, rather than just rhythm status, was a better predictor of functional improvements in LAEF, functional status, and LVEF.
• Restoring atrial contractile function, indicated by LAEF, is crucial for recovery in HFrEF patients.