Successful atrial fibrillation ablation following bariatric surgery in Japanese patients with extreme obesity

Abstract

Obesity is a significant risk factor for the development and progression of atrial fibrillation (AF) and is associated with poor outcomes following AF ablation. We present two compelling cases of extremely obese Japanese patients with long-standing persistent AF who underwent laparoscopic sleeve gastrectomy (LSG) prior to successful radiofrequency catheter ablation (RFCA). Both patients maintained sinus rhythm for over 4.5 years post-RFCA, with notable improvements in cardiac parameters, such as reduced left atrial size, and favorable metabolic profiles, including improved glycemic control and decreased N-terminal pro-B-type natriuretic peptide levels. These cases underscore the crucial benefits of weight reduction strategies, particularly bariatric surgery, as a preparatory intervention for AF ablation in this challenging patient population. While severe obesity (body mass index ≥35 kg/m²) has historically been less common in Japan, its prevalence is increasing. This trend highlights a growing number of patients who could benefit from interventions such as LSG. Our report emphasizes the importance of integrating bariatric surgery into the management paradigm for obese AF patients in Japan, demonstrating its efficacy and the growing relevance of a multidisciplinary approach focusing on substantial weight reduction to enhance AF ablation outcomes.

Learning objective

This case report highlights the significant impact of bariatric surgery on improving catheter ablation outcomes for atrial fibrillation (AF) in extremely obese patients. It demonstrates how substantial weight reduction can lead to favorable cardiac remodeling and metabolic improvements, enhancing long-term rhythm control after ablation. We emphasize the growing importance of a multidisciplinary approach that integrates weight management into the overall treatment strategy for obese AF patients.

Introduction

Obesity has emerged as a significant risk factor for the development and progression of atrial fibrillation (AF) and is associated with poor outcomes following AF ablation. A retrospective study showed that bariatric surgery before AF ablation in patients with morbid obesity was associated with >3-fold reduction in AF recurrence rates [1]. The interaction between obesity and AF is complex and multifactorial, involving changes in cardiac structures. Bariatric surgery has shown multiple positive effects in patients with extreme obesity. In Japan, severe obesity is rare; however, we encountered two patients who underwent successful ablation therapy after bariatric surgery. This report reviews the current understanding of the relationship between obesity, weight loss, and AF. We also reconsidered the effect of bariatric surgery in managing AF in patients with extreme obesity. Finally, we highlight the importance of comprehensive management combining obesity treatment and AF ablation in AF patients with extreme obesity.

Case report

Case 1

A 52-year-old man with obesity [body mass index (BMI) 35.5 kg/m²], hypertension, and diabetes was diagnosed with AF in 2021. He was treated with oral hypoglycemics including a glucagon-like peptide (GLP)-1 receptor agonist. Three months later, the patient was referred to our hospital for the treatment of AF. Electrocardiography revealed AF rhythm. His HbA1c and N-terminal pro-B-type natriuretic peptide (NT-pro BNP) levels at the first visit were 8.8 % and 542 pg/mL, respectively. Echocardiography revealed a left atrial diameter (LAD) of 48 mm, left atrial volume (LAV) of 106 mL, and left atrial volume index (LAVI) of 50 mL/m². Antiarrhythmic drug therapy, initially with flecainide (200 mg/day) and later with bepridil (200 mg/day) for four months, proved ineffective. The patient was diagnosed with long-standing persistent AF (LSPAF), and the time from his initial diagnosis to his first visit to our hospital was at least one year. One year later, the patient underwent a laparoscopic sleeve gastrectomy (LSG) for extreme obesity. Three months after the LSG, his HbA1c level decreased to 6.4 %, and oral hypoglycemics were discontinued. Six months after LSG, his BMI decreased to 29.5 kg/m², and he underwent radiofrequency catheter ablation (RFCA). The procedure included pulmonary vein isolation (PVI), cavo-tricuspid isthmus (CTI) ablation, and posterior wall isolation (PWI). To prevent esophageal injury, a luminal esophageal temperature probe was used continuously, and ablation was performed with high-power, short-duration radiofrequency energy on the posterior wall. The bepridil dose was gradually tapered and discontinued. His NT-pro BNP level had decreased to 147 pg/mL at the 3-month follow-up after RFCA. His LAD, LAV, and LAVI decreased to 47 mm, 76 mL, and 39 mL/m², respectively. The patient maintained sinus rhythm for more than 4.5 years after the RFCA. At his most recent outpatient visit, his obesity was well-managed with a BMI of 28.4 kg/m², he maintained an HbA1c of 6.8 % without hypoglycemic agents, and his LAVI was 42 mL/m² (Fig. 1).

Fig. 1.

Clinical course of case 1.

(A) 12‑lead electrocardiography at the first visit.

(B) Echocardiography (4-chamber view) at the first visit (left) and 3 months after RFCA (right).

(C) Pre- and post-LSG change in LAVI and BMI.

(D) Pre- and post-LSG change in HbA1c and NT-pro BNP levels.

LSG, laparoscopic sleeve gasterectomy; OHAs, oral hypoglycemic agents; RFCA, radiofrequency catheter ablation; LAVI, left atrial volume index; BMI, body mass index; NT-pro BNP, N-terminal-pro-brain natriuretic peptide.

Case 2

A 53-year-old man was diagnosed with AF in 2015. At that time, the patient was extremely obese, with a BMI of 31.7 kg/m². His medical history included hypertension, hyperuricemia, dyslipidemia, chronic kidney disease, obstructive sleep apnea, and primary aldosteronism. He was referred to an arrhythmia outpatient clinic in 2018 and was started on oral bepridil at 200 mg/day. He underwent electrical cardioversion and returned to sinus rhythm but soon experienced AF recurrence, leading to the discontinuation of bepridil. He was then administered amiodarone (100 mg/day), which was ineffective. In March 2019, the patient underwent RFCA for LSPAF. Two months after the first RFCA, the patient experienced a recurrence of paroxysmal AF (PAF) despite continuing amiodarone therapy, at which time his BMI had increased to 36.4 kg/m2. The patient visited our outpatient clinic in October 2019. His NT-pro BNP level at the first visit was 1196 pg/mL. He was pharmacologically cardioverted to sinus rhythm in April 2020, and his NT-pro BNP decreased to 215 pg/mL in June 2020. Despite weight loss guidance for severe obesity, no improvement was observed. In 2021, the patient underwent LSG. One month after the LSG, his NT-pro BNP decreased to 50 pg/mL. Amiodarone was gradually tapered and discontinued 3 months after LSG because of thyroid dysfunction. Six months after LSG, his BMI decreased to 28.1 kg/m², and he underwent a second RFCA for recurrent PAF. Due to electrical reconduction of the bilateral pulmonary veins, the patient underwent repeat PVI, CTI ablation, and PWI. Before the second RFCA, the LAD was 47 mm, LAV was 90 mL, and LAVI was 42 mL/m². One year after the second RFCA, the LAD, LAV, and LAVI had decreased to 46 mm, 73 mL, and 34 mL/m², respectively. The patient maintained sinus rhythm for over 4.5 years after the second RFCA. At the most recent outpatient visit, his BMI was 30.5 kg/m² and LAVI was 22 mL/m² (Fig. 2). In both cases, AF recurrence was monitored by 12‑lead electrocardiogram at each outpatient visit and 24-hour Holter monitoring was performed at 3, 6, and 12 months, and annually thereafter.

Fig. 2.

Clinical course of case 2.

(A) 12‑lead electrocardiography at the first visit.

(B) Echocardiography (4-chamber view) at the first visit (left) and 3 months after the second RFCA (right).

(C) Pre- and post-LSG change in LAVI and BMI.

(D) Pre- and post-LSG change in NT-pro BNP.

LSG, laparoscopic sleeve gasterectomy; RFCA, radiofrequency catheter ablation; LAVI, left atrial volume index; BMI, body mass index; NT-pro BNP, N-terminal-pro-brain natriuretic peptide.

Discussion

Obesity is closely associated with left atrial enlargement as well as new-onset and perpetuation of AF. Obesity and AF share key pathophysiological links, including inflammation and oxidative stress, atrial electrical and structural remodeling, left ventricular remodeling, and epicardial adipose tissue [2]. Extreme obesity (BMI ≥40 kg/m²) was associated with very low single-procedure ablation success rates, especially for non-paroxysmal AF. Another retrospective analysis suggested a higher BMI (≥35 kg/m²) is associated with more comorbidities and more persistent/long-standing AF and adversely impacts long-term ablation success rates in patients who underwent AF ablation. Furthermore, BMI ≥40 kg/m² increases the risk of minor procedural complications [3].

Several studies have demonstrated the impact of weight loss on the incidence and outcomes of AF [1,3]. Weight loss through lifestyle modification and risk factor management improves the AF burden, symptom severity, and cardiac remodeling. Greater degrees of weight loss (>10 %) are associated with better arrhythmia-free survival and potential reversal of AF disease progression [4]. An observational study suggested that bariatric surgery before AF ablation in patients with morbid obesity was associated with a greater than 3-fold reduction in AF recurrence rates. It recommended considering bariatric surgery evaluation for patients with morbid obesity before ablation. The beneficial effects may be mediated through improvements in weight, glycemic control, blood pressure, and reduction in epicardial fat after bariatric surgery [1]. Other changes, such as gut hormone and mitochondrial function and decreased inflammation, possibly lead to improved cardiac function and liver and renal function through mechanisms associated with the reversal of tissue fibrosis in patients with diabetes [5]. In our case, Case 1 showed substantial improvement in HbA1c, which probably provided a synergistic effect to suppress AF recurrence.

Bariatric surgery also promotes favorable cardiac remodeling [6]. For example, concentrations of vasoconstrictors, such as angiotensin II, renin, and endothelin-1, significantly decrease by 6 months after bariatric surgery, which leads to a further reduction in afterload and alleviates the pressure load on the heart, particularly the left atrium [5]. In both cases, the size of the left atrium decreased after bariatric surgery and RFCA. In Case 2, while the initial NT-proBNP reduction was mainly due to restoring sinus rhythm, its further decrease to 50 pg/mL post-LSG suggests an additional benefit from reduced cardiac load through weight loss, implying a synergistic effect of these two factors on cardiac function. Furthermore, in morbid obesity, bariatric surgery reduces AF recurrence rates to levels similar to those of non-obese patients after ablation [7].

Metabolic surgery in Japan has been performed safely and effectively over the past 20 years, with an increasing number of LSG procedures in recent years after receiving full insurance coverage in 2014 [8]. However, the adoption of these procedures in Japan has been sluggish, partly due to stringent insurance criteria that are stricter than in many Western countries, the low prevalence of extreme obesity, and a limited number of qualified facilities. Moreover, contributing factors likely include cultural views, such as a reluctance toward abdominal surgery and a perception of obesity as a matter of personal responsibility rather than a treatable disease. These are combined with systemic barriers, including a limited understanding of surgical benefits and the historical lack of insurance coverage until 2014. While a shorter duration from diagnosis to ablation is generally associated with better outcomes [9], this principle may not be directly applicable to patients with severe obesity. A multidisciplinary approach is essential for these patients. New anti-obesity medications are emerging as a promising first-line therapy. The recent LEAF study provided evidence for this, showing that even a modest pre-ablation weight loss of ≥3 %, achieved with a GLP-1 receptor agonist-based program, significantly improved freedom from AF [10]. While new anti-obesity medications are a promising first-line therapy, bariatric surgery remains a crucial option for unresponsive patients. For this high-risk population, balancing the risk of AF progression against the poor outcomes of ablating a metabolically unprepared patient presents a critical clinical challenge. Our experience suggests that, even in Japanese patients, a strategy prioritizing significant weight loss before ablation may lead to better long-term outcomes. However, further research is needed to confirm the benefits of this approach and to establish the optimal therapeutic timing.

Consent statement

Written consent for publication was obtained from all patients, and they approved the final manuscript.

Declaration of competing interest

The authors have nothing to declare.