Characterization of arrhythmia-induced cardiomyopathy using magnetic resonance imaging in patients with persistent atrial fibrillation and left ventricular systolic dysfunction - insights from DECAAF II.

AIMS Atrial fibrillation (AF) ablation in heart failure reduces mortality and hospitalizations and improves ejection fraction. Arrhythmia-induced cardiomyopathy (AIC) is diagnosed after complete recovery of left ventricular systolic function after ablation. We aimed to identify the prevalence and pre-ablation predictors of AIC among patients with AF and left ventricular systolic dysfunction (LVSD). METHODS AND RESULTS We utilized the DECAAF II database, where 815 patients with persistent AF underwent late gadolinium enhancement cardiac magnetic-resonance imaging (LGE-CMR) before and 3 months after AF ablation. We only included patients with available left ventricular ejection fraction (LVEF) and LVSD. AF burden was continuously monitored. AIC was defined as LVSD and coexisting AF in patients with ejection fraction improvement to ≥50% following ablation. We identified 119 patients with LVSD and AF with a mean LVEF of 39.1 ± 7.8% and mean baseline fibrosis of 20.0 ± 7.3%. Mean AF burden post-ablation was 16.8 ± 20.2%, and mean LVEF recovery was 13.9 percentage points. Seventy-two patients (60.5%) fulfilled the criteria for AIC, and 47 (39.5%) did not. AIC patients had a mean baseline LVEF of 39.1 ± 7.9% (vs. 39.2 ± 7.9% in non-AIC patients; p = 0.9), a significantly lower percentage of fibrosis in the left atrial septal wall (12.2 ± 10.0% vs. 20.7 ± 11.4% in non-AIC patients, p < 0.001). Additionally, LVEF improvement was correlated with lower AF burden post-ablation (r = -0.23, p = 0.02). CONCLUSIONS In this post-hoc analysis of the DECAAF II trial, we found that the majority of patients with LVSD and persistent AF have AIC rather than primary cardiomyopathy. We identified LGE-CMR as a differentiator between AIC and other cardiomyopathies.