Conduction time around the mitral valve annulus has the potential to rule out postablation perimitral atrial tachycardia.

INTRODUCTION: It would be helpful in determining ablation strategy if the occurrence of perimitral atrial tachycardia (PMAT) could be predicted in advance. We investigated whether estimated perimitral conduction time (E-PMCT), namely, twice the time between coronary sinus (CS) pacing and the ensuing wave-front collision at the opposite side of the mitral annulus, correlated with the cycle length of PMAT and could predict future PMAT. METHODS AND RESULTS: We retrospectively (retrospective cohort) and prospectively (validation cohort) investigated atrial fibrillation patients who had received pulmonary vein isolation (PVI) and in whom left atrial maps had been created during CS pacing. We calculated their E-PMCT. PMAT was observed either by provocation or during follow-up in 25, AT other than PMAT was observed in 24 (non-PMAT AT group), and 53 patients never displayed any AT (no-AT group) in the retrospective cohort. In the PMAT group of the retrospective cohort, a strong positive correlation was observed between the PMAT CL and E-PMCT (r = .85, p < 0.001). PMAT was never induced nor observed in patients with E-PMCT less than 176 ms, and the best cut-off value for PMAT was 180 ms by receiver-operating characteristic curve analysis. In the validation cohort of 76 patients, the cut-off value of the E-PMAT less than 180 ms predicted noninducibility of PMAT, with a sensitivity of 78.6%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 25.0%. CONCLUSION: Short E-PMCT may predict noninducibility of PMAT and guide a less invasive ablation strategy.

Differences between typical and reverse typical atrial flutter identified by ultrahigh resolution mapping.

BACKGROUND: Although 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. METHODS: We 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. RESULTS: Baseline 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. CONCLUSION: Mapping 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.

Peri-procedural anticoagulation in patients with end-stage kidney disease undergoing atrial fibrillation ablation: results from the multicentre end-stage kidney disease-atrial fibrillation ablation registry.

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.

Treatment of atrial tachycardia arising after superior transseptal approach mitral valve surgery: Insights from ultra-high-density mapping to prevent atrioventricular block.

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.

Difference in radiofrequency ablation profile between during sinus rhythm and atrial fibrillation: Considerations in this era of high-power short-duration strategy.

Background: The concept of ablation index (AI) was introduced to evaluate radiofrequency (RF) ablation lesions. It is calculated from power, contact force (CF), and RF duration. However, other factors may also affect the quality of ablation lesions. To examine the difference in RF lesions made during sinus rhythm (SR) and atrial fibrillation (AF). Methods: Sixty patients underwent index pulmonary vein isolation during SR (n = 30, SR group) or AF (n = 30, AF group). All ablations were performed with a power of 50 W, a targeted CF of 5-15 g, and AI of 400-450 using Thermocool Smarttouch SF. The CF, AI, RF duration, temperature rise (Δtemp), impedance drop (Δimp), and the CF stability of each ablation point quantified as the standard deviation of the CF (CF-SD) were compared between the two groups. Results: A total of 3579 ablation points were analyzed, which included 1618 and 1961 points in the SR and the AF groups, respectively. Power, average CF, RF duration per point, and the resultant AI (389 ± 59 vs. 388 ± 57) were similar for the two rhythms. However, differences were seen in the CF-SD (3.5 ± 2.2 vs. 3.8 ± 2.1 g, p < .01), Δtemp (3.8 ± 1.3 vs. 4.0 ± 1.3°C, p < .005), and Δimp (10.3 ± 5.8 vs. 9.4 ± 5.4 Ω, p < .005). Conclusions: Despite similar AI, various RF parameters differed according to the underlying atrial rhythm. Ablation delivered during SR demonstrated less CF variability and temperature increase and greater impedance drop than during AF.

Surgical Excision of a Left Atrial Mobile Stalked Calcification Arising After Multiple Radiofrequency Ablations.

We report a rare case of a mobile ectopic calcification in the left atrium requiring surgical excision 9 years after multiple atrial fibrillation ablations. (Level of Difficulty: Intermediate.).