The volume of left atrium measured by multi-detector computed tomography can predict of long term outcome in catheter ablation of atrial fibrillation

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background This study aimed to identify the volume left atrium (LA) and left atrial appendage (LAA) calculated by multidetector computed tomography (MDCT) is related to the long term out come of radiofrequency catheter ablation (RFCA) for atrial fibrillation(AF). Methods We analyzed data from 99 consecutive patients who referred for RFCA due to drug-refractory symptomatic AF (age 56 ± 10 years; 74% men; 64% paroxysmal AF). Prior to the procedure, all patients underwent ECG-gated 128 channels MDCT scan for assessment for pulmonary vein anatomy, LA and LAA volume estimation, and electro-anatomical mapping integration. Results The volume of LA and LAA calculated by CT was 142.6 ± 32.2 mL and 14.7 ± 6.0 mL, respectively. LA volume was smaller in paroxysmal AF(PAF) than persistent AF(PeAF) (133.9 ± 29.3 mL vs. 158.0 ± 31.4 mL, p < 0.0001) but LAA volume was not significantly different between PAF and PeAF(13.9 ± 5.0 mL vs. 16.3 ± 7.3 mL, p = 0.09). Patients were classified into 2 groups by the LA volume of 160mL; group 1 (LA volume < 160mL,n = 73) and group 2 (LA volume ≥160mL, n = 26). After a mean follow up 12.6 ± 5.3 months, 78.8% of the patients maintained sinus rhythm after the index ablation. AF free survival was significantly greater in group 1 than group 2 (84.9% vs. 61.5% p = 0.017). No relationship was found between LAA volume and the outcome of RFCA. Multivariate analysis showed that the LA volume >160mL was an independent predictor of arrhythmia-free after ablation (Hazard ration 2.55, 95% confidential interval 1.02-6.35, p = 0.045) Conclusion Higher LA volume is independent risk factor for AF recurrence after RFCA but not LAA volume. The LA volume quickly assessed by MDCT could be a good predictor of long term recurrence after AF ablation.