Introduction Mitral valve surgery employing a superior transseptal approach (STA) is associated with arrhythmogenicity and intra‐atrial conduction delay, despite being optimal for visualization of the surgical field. It is sometimes difficult to treat atrial tachycardias (AT) that arise after STA. To investigate AT circuits that arise after STA in detail in order to identify the optimal ablation line, using ultra‐high‐resolution mapping (UHRM). Methods We retrospectively analyzed 12 AT from 10 patients (median age 70 years, nine males) who had undergone STA surgery. The tachycardias were mapped using the Rhythmia mapping system (Boston Scientific, Natick, Massachusetts). Results The 12 STA‐related AT (STA‐AT) circuits were classifiable as follows according to location of the optimal ablation line: (1) peri‐septal incision STA‐AT (n = 3), (2) cavotricuspid isthmus (CTI) dependent STA‐AT (n = 7), and (3) biatrial tachycardia (n = 2). Radiofrequency (RF) application terminated 11 of the 12 STA‐AT. We found that difference in STA‐AT circuit type was due to characteristics of the septal incision line made for STA. UHRM was important in identifying optimal ablation sites that did not create additional conduction disturbances in the right atrium (RA). Conclusions ATs after STA involve complex arrhythmia circuits due to multiple and long incision lines in the RA. Accurate understanding of the arrhythmia circuit and sinus conduction in the RA after STA is recommended for treating post‐surgical tachycardia in a minimally invasive manner.

No abstract

Aims The optimal anticoagulation regimen in patients with end-stage kidney disease (ESKD) undergoing atrial fibrillation (AF) catheter ablation is unknown. We sought to describe the real-world practice of peri-procedural anticoagulation management in patients with ESKD undergoing AF ablation. Methods and results Patients with ESKD on haemodialysis undergoing catheter ablation for AF in 12 referral centres in Japan were included. The international normalized ratio (INR) before and 1 and 3 months after ablation was collected. Peri-procedural major haemorrhagic events as defined by the International Society on Thrombosis and Haemostasis, as well as thromboembolic events, were adjudicated.  A total of 347 procedures in 307 patients (67 ±9 years, 40% female) were included. Overall, INR values were grossly subtherapeutic [1.58 (interquartile range: 1.20–2.00) before ablation, 1.54 (1.22–2.02) at 1 month, and 1.22 (1.01–1.71) at 3 months]. Thirty-five patients (10%) suffered major complications, the majority of which was major bleeding (19 patients; 5.4%), including 11 cardiac tamponade (3.2%). There were two peri-procedural deaths (0.6%), both related to bleeding events. A pre-procedural INR value of 2.0 or higher was the only independent predictor of major bleeding [odds ratio, 3.3 (1.2–8.7), P = 0.018]. No cerebral or systemic thromboembolism occurred. Conclusion Despite most patients with ESKD undergoing AF ablation showing undertreatment with warfarin, major bleeding events are common while thromboembolic events are rare.

BackgroundAlthough atrial flutter (AFL) is a common arrhythmia that is based on a macro‐reentrant tachycardia around the tricuspid annulus, the factors giving rise to typical AFL (t‐AFL) versus reverse typical AFL (rt‐AFL) are unknown. To investigate the difference between t‐AFL and rt‐AFL circuits using ultrahigh resolution mapping of the right atrium.MethodsWe investigated 30 isthmus‐dependent AFL patients (mean age 71, 28 male) who underwent first‐time cavo‐tricuspid isthmus (CTI) ablation guided by Boston Scientific's Rhythmia mapping system and divided them into two groups: t‐AFL (22 patients) and rt‐AFL (8 patients). We compared the anatomy and electrophysiology of their reentrant circuits.ResultsBaseline patient characteristics, use of antiarrhythmic drugs, prevalence of atrial fibrillation, AFL cycle length (227.1 ± 21.4 vs. 245.5 ± 36.0 ms, p = .10), and CTI length (31.9 ± 8.3 vs. 31.1 ± 5.2 mm, p = .80) did not differ between the two groups. Functional block was observed at the crista terminalis in 16 patients and at the sinus venosus in 11. No functional block was observed in three patients, all of whom belonged to the rt‐AFL group. That is, functional block was observed in 100% of the t‐AFL group as opposed to 5/8 (62.5%) of the rt‐AFL (p < .05). Slow conduction zones were frequently observed at the intra‐atrial septum in the t‐AFL group and at the CTI in the rt‐AFL group.ConclusionMapping with ultrahigh‐resolution mapping showed differences between t‐AFL and rt‐AFL in conduction properties in the right atrium and around the tricuspid valve, which suggested directional mechanisms.

No abstract