Catheter ablation in rate-controlled atrial fibrillation with severely reduced ejection fraction: intervention for irregularity-mediated cardiomyopathy.

Background: Recent evidence suggests atrial fibrillation (AF) causes cardiomyopathy due to remodeling driven by both irregular rate and rhythm. Atrial fibrillation (AF) ablation in patients with reduced ejection fraction (EF) ≤ 35% has been shown to improve EF and mortality. It is unknown whether the benefits of AF ablation among patients with reduced EF are affected by the degree of pre-ablation rate control.

Objectives: To evaluate AF ablation echocardiographic outcomes for patients who have EF ≤ 35% with varying degrees of pre-ablation rate control.

Methods: Single-center, retrospective study of patients with EF ≤ 35% undergoing first-time ablation of persistent AF. Primary analyses evaluated the degree to which pre-ablation rate control impacted echocardiographic outcomes. Rates of EF recovery to > 35% were compared at three different cutoffs: 110 bpm, 90 bpm, and 70 bpm. A linear regression analysis was then performed to evaluate whether baseline heart rate (HR) predicted change in EF.

Results: Among 73 patients, the mean pre-ablation resting HR was 90 ± 25 bpm, and baseline EF was 27 ± 7%. Patients experienced significant improvements in EF by mean + 14% ± 11% (p < 0.001). Post-ablation EF recovery occurred in 60% of patients. No differences in EF improvement were detected at HR control targets of ≤ 110 bpm or ≤ 90 bpm, while patients achieving HR ≤ 70 bpm had less improvement in EF (+ 9% ± 9%) compared to those with HR above the cutoff (+ 16% ± 11%; p = 0.01). Linear regression analysis did not reveal baseline HR as a significant predictor of change in LVEF (slope = 0.09, r = 0.05, p = 0.07).

Conclusions: Catheter ablation of persistent AF in patients with reduced EF frequently resulted in recovery in EF > 35%, irrespective of pre-ablation achieved rate control. While patients with HR > 70 bpm experienced a greater improvement in EF compared to those ≤ 70 bpm, patients with baseline HR below this target still experienced significant EF improvements. Further investigation into irregularity-mediated cardiomyopathy is warranted.