Introduction: The outcome of atrial fibrillation (AF) ablation is suboptimal in overweight patients. This study reports the relationship of overweight patients and AF ablation outcome from a high-volume UK centre (>250 per year).
Methods: The study population consisted of 283 patients (mean age 62 ± 11 years, 61% male) who underwent their first-time AF ablation at Queen Elizabeth Hospital (QEH) Birmingham in 2018–2019. Recurrence of AF (AF >30 s, symptomatic recurrence) at 1 year (365 days) after 90-day blanking period was reviewed. Recurrence and no recurrence groups were compared according to body mass index (BMI), indexed left atrial (LA) volume and ablation methods.
Results: Mean BMI was 29.3 ± 5 kg/m2 and 111 (39%) patients were obese (BMI >30) at ablation despite risk factor (RF) modification advice at clinic. A total of 35 patients (12%) with morbid obesity (BMI >35 kg/m2) had higher prevalence of diabetes (1.7% in BMI <25 vs 22.9% in BMI >35; p=0.002), hypertension (18.3% in BMI <25 vs 57.1% in BMI >35; p<0.001) and sleep apnoea (nil in BMI <25 vs 20% in BMI >35; p<0.001). Overall, 25 patients (10%) had impaired left ventricular function (<50%) on echocardiography, and 109 patients (45%) had dilated indexed LA volume (>34 mL/m2) with mean 34.2 ± 12.5 mL/m2. In total, 15 patients (5%) had at least moderately severe valvular heart diseases. Single-procedure success rate in the cohort was 76% (74% pulmonary vein isolation only). The only predictor of outcome in our cohort between the recurrence vs no recurrence groups was indexed LA volume (37.1 ± 14.4 vs 33.3 ± 11.7 mL/m2; p=0.04). Higher BMI patients (BMI >30 and BMI >35) tended to have worse outcomes; however, results were not statistically significant (no recurrence 39.1% vs recurrence 39.7% in BMI >30 group, p=0.92; and no recurrence 9.8% vs recurrence 16.2% in BMI >35 group, p=0.14) (Table 1).
Conclusion: The success rate of first-time AF ablation at QEH was better than the published research data despite nearly 40% of our cohort consisting of obese patients with dilated LA. Obesity alone may not be a sufficient marker of poor outcome with ablation, but if associated with adverse LA remodelling, outcomes are poorer. Further mechanistic research is needed to optimise patient selection prior to catheter ablation. ❑