Left atrial strain is associated with atrial fibrillation recurrence after catheter ablation: Data from the ISOLATION registry
Authors: Gawalko M , Adriaans B , Habibi Z , Weerts J , Posea P , Hubers S , Verhaert D , Chaldoupi S M , Ter Bekke R , Den Uijl D , Luermans J , Van Empel V , Schotten U , Vernooy K , Linz D 
Published: May 2023

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background
Catheter ablation (CA) has been established as an effective therapeutic option to achieve rhythm control in patients with atrial fibrillation (AF). However, AF recurrence occurs in approximately 45% of the patients undergoing CA. The association between AF recurrence after CA and left atrial (LA) strain, which is a surrogate marker of LA mechanical dysfunction already appearing before the enlargement of the LA, remains less clear.

Aim
The purpose of this study was to evaluate the association between LA function assessed by strain echocardiography and AF recurrence after CA.

Methods
This sub-study of ISOLATION (NCT04342312), involved consecutive patients with paroxysmal or persistent AF scheduled for first cryoballoon or radiofrequency CA. Clinical characteristics and echocardiography examination were collected at baseline visit before CA. Patients were followed for 12 months. Follow-up consisted of outpatient visits and heart rhythm monitoring (48 day Holter, 12-lead electrocardiogram, 7 day photoplethysmography-based rhythm app) at 3, 6, and 12 months.

Results
We analyzed 312 patients (median age 65, 36% women). More than half (52%; n=162) underwent radiofrequency CA and 84 (27 %) had AF recurrence within one year follow-up. No statistically significant differences in baseline characteristic were observed between patients with and without recurrent AF, expect higher prevalence of persistent AF prior to CA in patients with recurrence of AF (75% vs. 46%, p&lt;0.001). LA reservoir strain (22 [14-33]% vs 29 [19-37]%, p=0.002), LA conduit strain (15 [9.6-19]% vs 17 [12-22]%, p=0.038) and LA contraction strain (7.5 [2.2-15]% vs 12 [5.8-16]%, p&lt;0.001), were significantly lower, and mildly-to-severe LA dilatation (≥39mm in women and ≥41–in men) was more frequently observed (77% vs 64%, p=0.039) in patients with (vs without) recurrence of AF. Based on multiple logistic regression, LA contraction strain was an independent predictor for AF recurrence (OR 0.94, 95%CI 0.90-0.98) in all study group. LA contraction strain of ≤9.4% had a sensitivity of 61% and specificity of 58% for recurrence of AF after CA. In the group with normal LA (&lt;39mm in women and &lt;41–in men), LA reservoir strain was significantly associated with the risk for recurrence of AF (OR 0.94 [0.90–0.99]). Overall, LA reservoir strain of ≤29% in this group had a negative predictive value of 90% and sensitivity of 74% for recurrence of AF after CA (Figure 1). AF type was not predictive in this subgroup. In the group with mildly-to-severe enlarged LA, AF type remained strongly predictive for recurrence of AF (OR 3.38[1.82-6.25]), whereas LA strains did not.

Conclusions
LA function assessed by LA strain is associated with AF recurrence after CA, even in patients with non-dilated LA. Whether integration of results derived from systematic preprocedural LA strain analysis into patients’ selection strategies may help to identify patients profiting from CA required further study.