Selection Bias Exists for Selection of Contemporary Atrial Fibrillation Ablation Patients

Introduction: Trends in catheter ablation for atrial fibrillation are evolving, with greater numbers of patients with more co-morbid risk factors undergoing this procedure. Demographic and risk factor profiles in this sub-group are often assumed to represent that of the general AF population. We examined the demographic and risk factor profile of patients presenting for AF ablation procedures compared to those presenting to the Emergency Room (ER) for the acute treatment of AF. Methods: 450 patients with an ICD-10 coding I48 admitted to a University Hospital over a seven month period were evaluated. Patients presenting for cardioversions, pacemaker implantations, transthoracic echocardiograms, and those with insufficient hospital data were excluded. Patient characteristics and disease profiles were obtained for the remaining 253 (56.2%) acute and 66 ablation patients (14.7%). Results: Acute management (79.3%) of AF was associated with older patients and greater co-morbidity burden (Figure). The main co-morbid characteristics that distinguished this cohort from the AF ablation cohort (20.7%) were older age (P < 0.001) and higher prevalence of HT, CHF, CAD, or stroke/TIA (P ≤ 0.05). Other predictors included hypercholesterolaemia and history of myocardial infarction (P = 0.03). Conclusions: Our data demonstrate the magnitude of selection bias for contemporary AF ablation patients. AF ablation patient risk profiles and outcomes should be extrapolated to the general AF community with caution.