Treatment-Related Changes in Left Atrial Structure in Atrial Fibrillation: Findings From the CABANA Imaging Substudy

Abstract

Background - The Catheter Ablation versus Antiarrhythmic Drug Therapy for Atrial Fibrillation (CABANA) trial was a randomized, prospective trial of left atrial catheter ablation versus drug therapy for treatment of atrial fibrillation (AF). As part of CABANA, a prospective imaging sub-study was conducted. The main objectives were to describe the patterns of changes in the dimensions of the left atrium (LA) and pulmonary veins (PVs), and the relationship between these changes with treatment assignment and clinical outcomes. Methods - CT or MRI was acquired at baseline and follow-up in 121 ablation (median follow-up 101 days) and 85 drug patients (median follow-up 97 days). Left atrial volume index (LAVI), mean PV ostial diameter (MPV) , and ostial diameters of each PV separately were computed. We examined the relationship between the change from baseline to follow-up with subsequent clinical outcomes (composite of death, disabling stroke, serious bleeding, or cardiac arrest [CABANA primary endpoint], total mortality or cardiovascular hospitalization, first AF recurrence after the 90 day blanking period, first AF/atrial flutter/ atrial tachycardia after the 90 day blanking period) using Cox proportional-hazards models. Results - The median (25 th , 75 th ) change from baseline for LAVI was -7.8 mL/m 2 (-16.4, 0.2), ablation arm and -3.5 mL/m 2 (-11.4, 2.6), drug therapy arm. The LAVI decreased in 52.9% of ablation patients versus 40.0% of drug therapy patients. Change for MPV was -2.7 mm (-4.2, -1.3) in the ablation arm versus -0.1 mm (-1.5, 0.8) in the drug therapy arm. Changes in LA and PV dimensions had no consistent relationship with the risk of developing the study primary endpoint. Reductions in LAVI, and in MPV diameter were associated with decreased risk of AF recurrence. Conclusions - Ablation patients demonstrated more frequent and larger atrial structural changes compared with drug patients. These changes suggest a critical relationship between structural features and AF generation.

Impact of pulmonary vein variant anatomy and cross-sectional orifice area on freedom from atrial fibrillation recurrence after cryothermal single-shot guided pulmonary vein isolation

“…A prior study suggested a critical relationship between structural alterations of LA tissue and AF initiation addressing that PV dimensions seem to have a greater impact on AF recurrence than the pure size of the LA [23] and these findings are in line with our observations. Thus, preprocedural imaging and the estimation of the CSOA may help to identify patients who benefit most from single-shot device-guided PVI.…”

Identifying Atrial Fibrillation Mechanisms for Personalized Medicine

“…Intriguing GWAS studies have recently identified genetic loci for atrial dilatation [ 57 ]. A smaller LA volume index was associated with a lower risk for AF recurrence in the CABANA trial of ablation or pharmacotherapy [ 58 ]. Increasing data implicates right atrial enlargement in conferring a worse prognosis after ablation or cardioversion [ 59 , 60 ].…”

Atrial Fibrillation: The Year of 2021 in Review

“…In the CABANA imaging substudy, approximately 200 patients had pre-procedural and follow-up imaging (mean, 100 days) with either cardiac computed tomo graphy or magnetic resonance imaging (MRI) to quantify left atrial volumes and pulmonary vein (PV) diameter. 11 The left atrial volume index decreased 52.9% in the ablation group versus 40.0% in the AAD group. This finding is consistent with prior evidence that catheter ablation is associated with favorable remodeling that may result in long-term clinical benefits such as arrhythmia burden and stroke prevention.…”