Echocardiographic E/e for the prediction of recurrent atrial fibrillation after ablation or electrical cardioversion: a systematic review and meta-analysis
Authors: Gomez G , Tan M K C , Bailon D P , Te-Rosano A L D , Jimenez R M , Tiongco R.H.P.I.I , Bernardo J J G 
Published: October 2021

Abstract

Background
Atrial Fibrillation (AF) is the most common arrhythmia, with important sequelae if left untreated. Markers help to predict the recurrence of AF after an intervention like ablation or electrical cardioversion (ECV). E/e' ratio is an echocardiographic marker which is potentially useful in predicting AF recurrence, however, present data is conflicting. Adding a simple tool like E/e' ratio to evaluation of patients for AF intervention may help in advising patients better about their risk for recurrent AF after intervention without adding much cost to the diagnostic work-up.

Purpose
To determine if there is a significant difference in pooled mean E/e' ratio among AF patients with recurrence after ablation or ECV compared to those who maintained sinus rhythm, and to determine the odds ratio of recurrent AF given an abnormal E/e' ratio.

Methods
The investigators systematically searched Pubmed, Medline, Cochrane Database, and Google Scholar for articles on patients undergoing catheter ablation or ECV for AF and who were adjudicated on recurrence of the arrhythmia. We calculated the weighted mean difference of E/e' ratio between those with recurring AF and those who maintained sinus rhythm, and the odds ratio of AF recurrence given an abnormal E/e' ratio. Statistical analysis was done using RevMan 5.4.1 software.

Results
A total of 38 studies involving 7048 patients were included in the initial analysis (26 studies on ablation with continuous data and 2 with dichotomous data based on a set cutoff, and 10 studies on ECV). One study was excluded due to absence of a blanking period and and another due to outlaying data in funnel plot analysis. The remaining 36 studies with 6910 patients were analyzed. There was a significant difference in the weighted mean E/e' ratio between the two groups in AF patients undergoing ablation (Mean Difference (MD)=0.60 (95% CI [0.20,1.00] p=0.003, I2=63%]), and ECV (MD=2.07 (95% CI [1.66, 2.49] p&lt;0.ehab724.0361, I2=12%), with an odds ratio of 1.88 (95% CI [1.04, 3.37] p=0.04, I2=52%) among those with dichotomous data. Subgroup analyses were done to reduce heterogeneity. E/e' ratio was not significantly different in the population of paroxysmal AF undergoing ablation (MD=0.64, 95% CI [−0.55, 1.83], p=0.29, I2=76%) but significantly different in patients with non-paroxysmal AF undergoing ECV (MD=2.19, 95% CI [1.82, 2.56], I2=0%).

Conclusion
This analysis suggests that a higher E/e' ratio may be used to predict recurrence of AF after ablation or ECV, especially in patients undergoing ECV. The heterogeneity of the data for E/e' ratio in AF ablation and the variety of co-morbid conditions to atrial fibrillation limits its clinical applicability. Further studies are recommended to determine the optimal cutoff of this ratio that would predict AF recurrence.

Funding Acknowledgement
Type of funding sources: None. Forest plot for studies on AblationForest plot for studies on ECV