May 30, 2018

Left atrial shape predicts recurrence after atrial fibrillation catheter ablation

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Atrial fibrillation (n=254). Intervention: Left atrial shape analysis vs. Clinical parameters and left atrial fibrosis alone. Primary outcome: Prediction of atrial fibrillation recurrence (Harrell's C-statistic) (C-statistic increased from 0.68 to 0.72, p=< 0.05).

Key Result

Left atrial shape analysis improved the prediction of atrial fibrillation recurrence after ablation when added to clinical parameters and fibrosis (C-statistic increased from 0.68 to 0.72; P<0.05).

Study Design

Type

Cohort (n=254)

PICO

Population

254 patients with atrial fibrillation who underwent cardiac MRI of the left atrium prior to catheter ablation, followed for up to 475 days.

Exposure / Comparator

Left atrial shape analysis vs Clinical parameters and left atrial fibrosis alone

Primary Outcome

Prediction of atrial fibrillation recurrence (Harrell's C-statistic) — C-statistic increased from 0.68 to 0.72, p=< 0.05

Main Result

Effect estimate: C-statistic increased from 0.68 to 0.72

p-value: p=< 0.05

Abstract

INTRODUCTION: Multiple markers left atrium (LA) remodeling, including LA shape, correlate with outcomes in atrial fibrillation (AF). Catheter ablation is an important treatment of AF, but better tools are needed to determine which patients will benefit. In this study, we use particle-based modeling to quantitatively assess LA shape, and determine to what degree it predicts AF recurrence after catheter ablation. METHODS AND RESULTS: There were 254 patients enrolled in the DECAAF study who underwent cardiac magnetic resonance imaging of the LA prior to AF ablation and were followed for recurrence for up to 475 days. We performed particle-based shape modeling on each patient's LA shape. We selected shape parameters using the LASSO method and factor analysis, and then added them to a Cox regression model, which included multiple clinical parameters and LA fibrosis. We computed Harrell's C-statistic with and without shape in the model. We used the model to stratify patients into recurrence risk classes by both shape and shape and fibrosis combined. Three shape parameters were selected for inclusion. The C-statistic increased from 0.68 to 0.72 when shape was added to the model (P < 0.05). Visualized shapes showed that a more round LA shape with a shorter, more laterally rotated appendage was predictive of recurrence. CONCLUSION: LA shape is an independent predictor of recurrence after AF ablation. When combined with LA fibrosis, shape analysis using PBM may improve patient selection for ablation.

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