How to Assess the Impact of Left Atrial Appendage Emptying Velocity on the Recurrence of Atrial Fibrillation After Catheter Ablation　― Reply ―

We are grateful for the opportunity to address the insightful comments raised by Imamura et al regarding our recent publication in the Circulation Journal,¹ which reported the clinical implication of left atrial appendage emptying velocity (LAAV) on the recurrence of atrial fibrillation (AF) after surgical ablation.

Imamura et al highlighted the prevalence of persistent AF among patients with lower LAAV in our cohort. It’s crucial to clarify that the manifestation of AF, whether persistent or paroxysmal, exhibits considerable variability, influencing LAAV measurements. Due to this heterogeneity, our analysis adjusted for rhythm status during transesophageal echocardiography (TEE) rather than categorizing by AF subtype. This adjustment aimed to mitigate the direct impact of rhythm at the time of measurement on LAAV, acknowledging the dynamic nature of AF. In the subgroup analysis, by only including patients with AF rhythm during TEE, LAAV was significantly associated with AF recurrence.

The evolution of our institutional approach to postprocedural electrophysiologic studies (EPS) and cavotricuspid isthmus (CTI) ablation has been guided by cumulative evidence and experience. Initially, routine EPS with CTI ablation aimed to preempt atrial flutter. However, shifting towards targeted ablation based on residual pulmonary vein potential reflects a nuanced strategy of prioritizing personalized patient care. This strategic change could potentially influence the clinical outcome of surgical AF ablation, as Imamura et al noted. However, the efficacy of routinely staged radiofrequency catheter ablation (RFCA) after surgical ablation remains debatable. In our institution, routine postoperative EPS with additional ablation did not offer significant benefits for AF recurrence.² Additionally, a randomized study does not support the routine use of EPS after surgical ablation.³ In line with previous studies, staged RFCA did not show a significant association with the risk of AF recurrence in our study, while LAAV was a significant predictor of AF recurrence in multivariate analysis.¹ Hence, despite the prevalent use of post-procedural RFCA in our study, LAAV may be a valuable tool for predicting AF recurrence in patients undergoing surgical ablation.

Concerning the role of the LAA in AF recurrence, Imamura et al’s observation about the exclusion of patients without LAA removal is pertinent. The LAA indeed represents a complex entity in AF pathology. Although our study focused on LAAV as a predictive marker, we acknowledge the multifaceted role of the LAA in AF recurrence.⁴ Future investigations are warranted to explore the intricate relationship between LAA morphology, LAAV, and AF outcomes, potentially including the impact of isoproterenol loading in enhancing LAAV assessment in patients with diminished velocities.

We thank Imamura et al for their valuable feedback, which underscores the complexity of AF management and the need for continued research into optimizing patient selection and therapeutic strategies in TTA. Our study contributes to this ongoing discourse, advocating for the integration of LAAV measurement in the preoperative evaluation to refine risk stratification for AF recurrence post-TTA.

• Jihoon Kim, MD
• Sung-Ji Park, MD, PhD
• Division of Cardiology, Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
• Dong Seop Jeong, MD, PhD
• Department of Thoracic and Cardiovascular Surgery, Cardiac and Vascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea

References

• 1.   Kim J, Bak M, Park SJ, Jeong DS, Chung S, Kim D, et al. Clinical implication of left atrial appendage emptying velocity in thoracoscopic ablation of atrial fibrillation. Circ J 2023; 87: 1742–1749.
• 2.   On YK, Park KM, Jeong DS, Park PW, Lee YT, Park SJ, et al. Electrophysiologic results after thoracoscopic ablation for chronic atrial fibrillation. Ann Thorac Surg 2015; 100: 1595–1602; discussion 1602–1603.
• 3.   Choi MS, On YK, Jeong DS, Park KM, Park SJ, Kim JS, et al. Usefulness of postprocedural electrophysiological confirmation upon totally thoracoscopic ablation in persistent atrial fibrillation. Am J Cardiol 2020; 125: 1054–1062.
• 4.   Di Biase L, Burkhardt JD, Mohanty P, Mohanty S, Sanchez JE, Trivedi C, et al. Left atrial appendage isolation in patients with longstanding persistent AF undergoing catheter ablation: BELIEF trial. J Am Coll Cardiol 2016; 68: 1929–1940.