The CAMERA-MRI Score to Predict LVEF Normalization Post Ablation for Primary Atrial Fibrillation Mediated Cardiomyopathy: a Pooled Analysis of Two Randomized Clinical Trials.
BACKGROUND Primary AF-mediated cardiomyopathy is a retrospective diagnosis in which left ventricular ejection fraction (LVEF) normalizes following catheter ablation. Identifying prospectively which patients will achieve LVEF normalization remains challenging. OBJECTIVE To determine predictors of LVEF normalization in AF-mediated cardiomyopathy patients following catheter ablation. METHODS This was a pooled analysis of the CAMERA-MRI and CAMERA-MRI II multicentre randomized trials, which included baseline and serial cardiac magnetic resonance (CMR). This sub-study included all patients who underwent catheter ablation. LVEF normalization predictors were assessed using univariable and multivariable logistic regression. Continuous variables were dichotomized to develop a practical score, internally validated through bootstrap resampling (200 iterations) and 5-fold cross-validation. RESULTS 113 patients (mean age 60.6±11.1, 13.3% female, 90.3% persistent AF, baseline LVEF 31.0±8.7%) were included, and 70 (63.7%) achieved LVEF normalization on serial CMR. On multivariable analysis, there were three independent predictors: normal indexed LV end-diastolic volume (OR=3.20, 95%CI 1.20-8.56, p=0.021), absence of alternate aetiology (OR=4.31, 95%CI 1.14-16.39, p=0.023), and absence of late gadolinium enhancement (OR=2.53, 95%CI 1.01-6.39, p=0.049), with an AUC of 0.788 (95%CI 0.703-0.873). Normalization likelihood by score was 12% (0/3), 38% (1/3), 67% (2/3), and 88% (3/3). CONCLUSION Absence of late gadolinium enhancement, normal LV volumes, and absence of an alternative aetiology identified the AF-induced cardiomyopathy phenotype most likely to achieve LVEF normalization following catheter ablation.