Impact of atrial fibrillation ablation on bi-atrial strain: differences between left and right atrial function

Background

Atrial strain is useful for assessing atrial function, and catheter ablation may improve atrial function in patients with atrial fibrillation (AF). During the cardiac cycle, left atrium (LA) changes in the following order: reservoir function, conduit function, and contractile function. Among these, LA reservoir strain (LASr) is an important index for quantifying LA function. Although changes in LA function before and after catheter ablation have been reported, few studies have examined changes in right atrial (RA) function in the 2D speckle-tracking.

Purpose

We retrospectively measured LA and RA strain before and after AF ablation and analyzed changes (Δ = post–pre). Moreover, we investigated the predictive value of LA and RA function for atrial tachyarrhythmias (AF/AT) recurrence.

Methods

We included patients with initial AF ablation (January–June 2024) who underwent transthoracic echocardiography within 3 months before and 3-12 months after AF ablation. LA and RA strain were measured by 2D speckle-tracking in apical 4- and 2-chamber views (LA: averaged; RA: 4-chamber) using EchoPAC 204 (GE Healthcare, Chicago, IL, USA). The R-wave on the electrocardiography trace was used as the temporal reference (zero baseline).

Results

Eighty-one patients were analyzed (mean age: 68.9 ± 9.8 years, male: n = 63, paroxysmal AF: n = 41). After AF ablation, RASr (18.3 ± 10.8 to 27.3 ± 9.3%, P < 0.001) as well as LASr (15.3 ± 10.0 to 19.9 ± 8.2%, P < 0.001) and significantly increased (Figure 1A, D). RASr was significantly increased compared to LASr (ΔRASr: 9.0 ± 10.7% vs. ΔLASr: 4.5 ± 8.4%, P < 0.001). Moreover, LA conduit strain (LAScd) did not change significantly from pre- to post-procedure (−9.3 ± 5.6 to −10.3 ± 4.4%, P = 0.071), whereas RA conduit strain (RAScd) improved significantly (−10.3 ± 6.3 to −14.1 ± 6.2%, P < 0.001) (Figure 1B, E). LA and RA contractile strain (LA/RASct) showed no significant pre–post change in patients who were in sinus rhythm at both examinations (Figure 1C, F).

Receiver operating characteristic analyses revealed that the predictive value of RASr was comparable to LASr (area under the curve (AUC), 0.69 vs. 0.75; P = 0.367) in the post-procedural echocardiography, with the optimal cut-off value of 20.0% (LASr) and 27.0% (RASr), respectively (Figure 2A). Log-rank analysis showed LASr ≤ 20.0% or RASr ≤ 27.0% on the post-procedural echocardiography were associated with AF/AT recurrence (Figure 2B,C). In separate multivariable models, both LASr (HR 0.92, 95%CI: 0.85-1.0, P = 0.049) and RASr (HR 0.94, 95%CI: 0.89-0.99, P = 0.016) emerged as independent predictors of AF/AT recurrence.

Conclusion

AF ablation led to significant bi-atrial functional recovery, with RA improvement exceeding LA. Both post-procedural LASr and RASr independently predicted AF/AT recurrence, supporting chamber-specific atrial strain as a sensitive marker of reverse remodeling and procedural outcome.