Main findings
We conducted a single center, retrospective analysis of 1346 patients undergoing index AF ablation, with a significant size female cohort in the study population, to investigate gender differences in outcomes and complications following catheter ablation of AF. We found that: diagnosis-to-ablation time for both groups was similar; although the number of EP appointments leading up to ablation was similar in men and women, women tried and failed more AADs than men prior to ablation; there were no gender-based differences in one-year arrhythmia recurrence rates; and procedure-related complication rates between men and women were similar.
Studies have shown that women with AF have a worse prognosis, including an increased risk of stroke, heart failure, and death, as well as more severe symptoms, a worse quality of life, and diminished functional capacity (5). Despite these facts, women are less likely to receive rhythm control through catheter ablation and cardioversion. Consequently, women often undergo ablation procedures at an older age and later in their disease course, often having experienced AF for a longer period with advanced cardiac remodeling resulting from the disease (5). While some studies suggest that females have a higher post-ablation arrhythmia recurrence rate than males, other studies like the CASTLE-AF trial did not show a gender difference in the effectiveness of ablation procedures. There remains ambiguity regarding gender-based differences in outcomes and complications related to AF ablation, partly because of the underrepresentation of women in these studies. Our study aimed to investigate gender-based disparities in the management of AF and as well as the outcome and complication rate of AF ablation procedures.
In contrast to most previous studies investigating gender impact on AF ablation, our study included a relatively large cohort of patients with a significantly higher proportion of female patients (n=450, 33.4% of total study patients). In accordance with existing studies, women were older at the time of ablation (66.2 vs 62.4 years; p<0.001). Compared to their male counterparts, women also tried and failed more anti-arrhythmic drugs before presenting for ablation procedure (1.13 vs 0.98; p=0.002). These results may indicate female patients’ apprehension towards procedural intervention, referral bias, or some other delaying factor. In contrast to previous studies (6), however, we found no significant difference in the duration of AF between men and women from initial diagnosis to ablation (44.6 months versus 44.1 m; p=0.97). At the time of diagnosis, it was observed that 25.3% of female patients had PersAF compared to 35.3% of male patients (p<0.001). Similarly, at the time of ablation, 31.8% of female patients had PersAF as opposed to 43.1% of male patients (p<0.001), suggesting a similar rate of progression from paroxysmal to PersAF in both genders.
With regards to procedural success, we found no significant difference in AF recurrence at 1-year post-ablation between male and female patients (27.7% vs 30%; p=0.38). This is consistent with previous studies (4,12,14) that have reported equal rates of procedural success and low recurrence rates in both genders. We believe it is more likely that the procedural results are primarily influenced by the consistency in timing of ablation from the time of diagnosis, regardless of gender. Timing of ablation is one of the major predictive factors of ablation outcomes due to advancement of atrial substrate. The study by Bunch et al. demonstrated that increasing time between diagnosis of atrial fibrillation and catheter ablation adversely affects long-term outcomes (20).
In prior research, it has been suggested that sex differences in outcomes can be partly explained by women having more advanced AF disease at the time of ablation (16). The prospective multicenter DECAAF study found a linear relationship between the degree of atrial fibrosis as identified by LGE-CMR and AF recurrence rates post-ablation (21) and another study by Chelu and colleagues correlated higher levels of atrial fibrosis with longer AF duration (22). Recent clinical trials EARLY- AF, CASTLE-AF, STOP-AF strongly advocate for early rhythm control using catheter ablation as a first line treatment for AF to reduce morbidity and mortality (23,24,25). With the growing evidence for early ablation, our study supports a uniform approach for all patients with regards to early ablation. Given a greater tendency to use antiarrhythmic drug therapy in women with AF, greater attention to counseling on therapeutic choices may be needed in this population (5).
In addition, no gender-related differences were observed in procedural complications, including vascular injury (7 males, 5 females; p=0.55), phrenic nerve injury (1 male, 1 female), pericardial effusion (6 males, 7 females; p=0.12), esophageal fistula (0 males, 0 females), or stroke/TIA (3 males, 1 female; p=0.71), supporting the recommendation that both men and women should be offered catheter ablation for atrial fibrillation on an equal basis. It should be acknowledged, however, that unlike most other studies in this area (15), our population did not demonstrate significant gender-based differences in the rates of comorbidities such as diabetes, hypertension, heart failure, chronic kidney disease, which may also be contribute to the lack of gender differences in procedural complications.
One of the key gender disparities in the management of AF is in the use of anticoagulation therapy. Studies have shown that women with AF are less likely to receive anticoagulation therapy compared to men, despite having similar or higher risk for stroke (3, 26). It is worth emphasizing, however, that women in our study were adequately treated with oral anticoagulants (92.2% females, 88.6% males; p=0.012), and that may partly explain the reduction in neurological adverse events.