Peak Frequency Annotation Algorithm Guided Slow Pathway Ablation in Typical Atrioventricular Nodal Re-entrant Tachycardia.

BACKGROUND: The slow-pathway potential is difficult to annotate because it is buried within the atrial potential. Omnipolar technology Near Field (OTNF) in Ensite X can automatically annotate the peak frequency potential associated with acquired intracardiac electrograms. OBJECTIVE: This study aimed to visualize the junction between the transitional cells and the slow pathway using a peak frequency map with OTNF and evaluate whether the high-frequency site around the tricuspid annulus (TA) is an effective target for slow pathway ablation. METHODS: This prospective observational study enrolled 37 patients with typical atrioventricular nodal re-entrant tachycardia. Patients underwent slow pathway ablation using peak frequency map (n = 17) and the conventional approach based on anatomical and electrophysiological findings (n = 20). RESULTS: High-frequency sites were distributed at the TA side of 4-5 o'clock in all peak frequency map-guided patients. The distance to His bundle from successful ablation site was farther (24.0 ± 4.8 vs. 12.7 ± 4.0 mm, p < 0.0001), junctional rhythm was slower (88 ± 17 vs. 115 ± 12 bpm, p < 0.0001), time to junctional rhythm after radiofrequency application was shorter (3.4 ± 1.4 vs. 8.2 ± 4.6 sec, p < 0.0001), and elimination rate of jump up (71 vs. 30%, p = 0.02) was higher in the peak frequency map-guided group. CONCLUSION: The high-frequency site of the TA at 4-5 o'clock in the peak frequency map could be a novel target of slow pathway ablation with high safety, efficiency, and efficacy.

Bipolar ablation involving coronary venous system for refractory left ventricular summit arrhythmias.

Background: Catheter ablation of premature ventricular complexes (PVCs) and ventricular tachycardia (VT) from the left ventricular summit (LVS) may require advanced ablation techniques. Bipolar ablation from the coronary veins and adjacent endocardial structures can be effective for refractory LVS arrhythmias. Objective: The aim of this study was to investigate the outcomes of bipolar ablation performed between the coronary venous system and adjacent endocardial left ventricular outflow tract (LVOT) or right ventricular outflow tract (RVOT). Methods: This multicenter study included consecutive patients with LVS PVC/VT who underwent bipolar ablation between the anterior interventricular vein (AIV) or great cardiac vein (GCV) and the endocardial LVOT/RVOT after failed unipolar ablation. Ablation was started with powers of 10-20 W and uptitrated to achieve an impedance drop of at least 10%. Angiography was performed in all cases to confirm a safe distance (>5 mm) of the catheter from the major coronary arteries. Results: Between 2013 and 2023, bipolar radiofrequency ablation between the AIV/GCV and the adjacent LVOT/RVOT was attempted in 20 patients (4 female; age 57 ± 16 years). Unipolar ablation from sites of early activation (AIV/GCV, LVOT, aortic cusps, RVOT) failed to effectively suppress the PVC/VT in all subjects. Bipolar ablation was delivered with a maximum power of 30 ± 8 W and total duration of 238 ± 217 s and led to acute PVC/VT elimination in all patients. No procedural-related complications occurred. Over a follow-up period of 30 ± 24 months, the freedom from arrhythmia recurrence was 85% (1 recurrence in the VT group and 2 in the PVC group). PVC burden was reduced from 22% ± 10% to 4% ± 8% (P <.001). Conclusion: In cases of LVS PVC/VT refractory to unipolar ablation, bipolar ablation between the coronary venous system and adjacent endocardial LVOT/RVOT is safe and effective if careful titration of power and intraprocedural angiography are performed to ensure a safe distance from the coronary arteries.

Cryoballoon ablation of peri-mitral atrial flutter refractory to radiofrequency ablation: a case report.

Background: The radiofrequency catheter ablation of peri-mitral atrial flutter is occasionally difficult, mostly due to epicardial or intramural conduction on the mitral isthmus (MI). However, cryoballoon ablation (CBA) of peri-mitral atrial flutter refractory to radiofrequency ablation has not been reported. Case summary: We report a case of a 66-year-old male patient who experienced a recurrence of atypical atrial flutter and underwent the sixth catheter ablation. The activation and entrainment maps showed that this atypical atrial flutter (AFL) was peri-mitral AFL via pathways other than endocardial conduction in the MI. Previous radiofrequency catheter ablation attempts on the MI line, including endocardial, coronary sinus, and epicardial ablations, failed to achieve a bidirectional block of the MI. In this case, we selected CBA for the MI area and successfully achieved a bidirectional block of the MI. Discussion: Although using CBA in the MI is off-label, it could be safely implemented using CARTOUNIVU™. We attributed the success of the bidirectional block of the MI in this case to the crimping of the northern hemisphere of the CBA to the mitral isthmus area, which resulted in the formation of a broad, uniform, and deep ablation lesion site.

A case report of Bow Hunter's syndrome with intravascular ultrasound showing changing significant severe stenosis of the left vertebral artery associated with turning left.

Background: Bow Hunter's syndrome is vertebral basilar artery insufficiency caused by mechanical occlusion of the vertebral artery during head rotation. This is often due to the formation of osteophytes, herniated discs, cervical spondylosis, or tumours. However, whether the contralateral vessel is organically stenotic is not well known. Case summary: A 79-year-old man was referred to our department for a close examination of syncope because the transient loss of consciousness occurring when he was made to turn his head to the left was reproducibly induced and recovered when his face was returned to the normal position. The carotid massage did not induce significant bradycardia or hypotension bilaterally, and Holter electrocardiography, echocardiography, head-up tilt test, coronary angiography, and an acetylcholine stress test showed no obvious abnormalities. A 3D CT angiography was performed to investigate the possibility of vertebrobasilar artery insufficiency, as C3/4 cervical spondylosis, and the left vertebral artery was compressed by the C4 superior process osteophyte, indicating hypoplasia of the contralateral vertebral artery. Vertebral artery angiography and intravascular ultrasound (IVUS) showed moderate stenosis of the left vertebral artery, and IVUS showed a half-circumferential calcified lesion. Compared to the midline position, the stenosis worsened at the site of compression and drainage when the patient turned left downward, and a diagnosis of Bow Hunter's syndrome was made. Discussion: Bow Hunter's syndrome is characterized by vertebrobasilar insufficiency. Intravascular ultrasound clearly showed that the lesion was not only stenotic due to compression but also had plaque growth due to continuous mechanical stimulation.

T-wave oversensing after implantation of pacemakers with automatic sensitivity adjustment in patients with atrioventricular block.

T-wave oversensing in pacemakers is rare because the set sensitivity is generally fixed. However, several models of pacemaker employ automatic sensitivity adjustment. Here, we present two cases of atrioventricular block treated by implantation of the pacemaker with automatic sensitivity adjustment. After implanting the pacemaker with automatic sensitivity adjustment, ventricular pacing suppression due to T-wave oversensing occurred. In both cases, T-wave oversensing disappeared after adjusting the setting sensitivity from 0.9 to 2.0 mV.

New-onset atrial high-rate episodes between his bundle pacing and conventional right ventricular septum pacing in patients with atrioventricular conduction disturbance.

BACKGROUND: The effect of His bundle pacing (HBP) on the incidence of new-onset atrial fibrillation (AF) after pacemaker implantation (PMI) for atrioventricular conduction disturbance (AVCD) remains unknown. We compared the incidence of new-onset atrial high-rate episode (AHRE) in conventional right ventricular (RV) septum pacing (RVSP) and His bundle pacing (HBP) after PMI for AVCD. METHODS: One hundred and four consecutive patients who underwent dual chamber PMI for AVCD in our hospital were screened. Thirty-five patients with mitral or aortic valve disease, history of open-heart surgery, prior AF, subclinical AF, cumulative ventricular pacing percentage < 90%, and RV lead revision were excluded, and 69 patients were effectively enrolled in this study. The primary endpoint was new-onset AHRE within the follow-up period. New-onset AHRE was defined as an atrial high-rate episode that occurred 3 months after PMI and lasted for > 6 min at an atrial heart rate > 190 bpm. RV leads were placed in the His bundle region and RV septum region in 22 and 47 patients, respectively. The mean follow-up period was 539 ± 218 days. The follow-up period was 2 years after PMI or until the new-onset AHRE occurred. RESULTS: The incidence of new-onset AHRE was lower in the HBP group than in the RVSP group (11% vs. 43%, p = 0.01). Multivariate analysis in the Cox regression hazard model showed that HBP had a significantly lower risk of new-onset AHRE compared with RVSP (HR = 0.21; 95% confidence interval 0.04-0.78, p = 0.02). CONCLUSION: The incidence of new-onset AHRE was significantly less in HBP compared to RVSP during the 2-year follow-up period after pacemaker implantation in AVCD patients with RV pacing dependence.

Trans-aortic mitral isthmus ablation after surgical patch closure for an atrial septal defect.

INTRODUCTION: In patients with prior atrial septal defect (ASD) closure and atrial tachyarrhythmias, transseptal puncture can be challenging. METHODS AND RESULTS: This case report discusses a 65-year-old man who had previously undergone pulmonary vein isolation (PVI) and cavo-tricuspid isthmus ablation for atrial fibrillation before ASD closure, respectively. He developed atrial tachycardia (AT) and underwent catheter ablation. AT was diagnosed as peri-mitral flutter and the mitral isthmus (MI) linear ablation via a trans-aortic approach successfully terminated it. CONCLUSION: This case demonstrates the feasibility and safety of transaortic MI linear ablation in patients with ASD closure devices or anatomical challenges when transseptal puncture is difficult.

Bidirectional rotating biatrial tachycardia.

A 72-year-old man was treated for recurrent atrial tachycardia (AT) and underwent ablation. The AT was diagnosed as bi-AT based on the activation map and the postpacing interval. Another AT appeared and was diagnosed as bi-AT by the same method. Surprisingly, the circuits of both ATs were perfectly matched and rotated in opposite directions. The left atrial anteroseptal wall was ablated during the AT. The AT was immediately stopped and was no longer induced.

Modification of the pulmonary vein antrum is associated with recurrence after durable pulmonary vein isolation for paroxysmal atrial fibrillation.

BACKGROUND: Although previous studies have shown the isolated areas after pulmonary vein isolation (PVI) using cryoballoons (CB) (CB-PVI), no studies have investigated the association between the isolated area and recurrence of atrial fibrillation (AF) and atrial tachycardia (AT). This single-center observational study investigated the association between the ablated area and recurrence rate after durable CB-PVI for paroxysmal AF. METHODS: This study included 76 patients with paroxysmal AF who underwent CB-PVI and established durable PVI with a second procedure, regardless of AF/AT recurrence, 6 months after the first procedure. To compare the ablated zones, we quantified the left- and right-sided PV antral isolation areas and non-ablated posterior wall (PW) area. We examined non-ablated areas of the PW and AF/AT recurrence in the chronic phase. RESULTS: In total, 16 of the 76 patients had AF/AT recurrence. The mean follow-up duration was 34 months. The non-ablated PW area (14.0 ± 4.6 cm2 vs. 11.5 ± 3.7 cm2; p = 0.0213) and the ratio of the non-ablated PW area to the whole PW area (NAPW) (52.9 ± 9.1% vs. 44.8 ± 9.8%; p = 0.003) were significantly higher in the AF/AT recurrence group than in the AF/AT non-recurrence group. NAPW > 50% was an independent predictor of AF/AT recurrence. CONCLUSION: The NAPW after durable CB-PVI is associated with AF/AT recurrence. PW isolation or additional applications on the PV antrum with cryoballoon may be considered in addition to PVI in paroxysmal AF, especially in patients with dilated left atria.

Visualization of the epicardial conduction through the Marshall bundle using the LUMIPOINT™ software.

The LUMIPOINT™ software allows visualization of arrhythmia circuits through the MB. In cases where the full extent of the arrhythmia circuit cannot be identified and epicardial conduction is suspected, it is better to perform the analysis while adjusting the confidence slider in LUMIPOINT™.

Association between residual unipolar voltage and arrhythmia recurrence after left atrial posterior wall isolation for persistent atrial fibrillation.

INTRODUCTION: Posterior wall isolation (PWI) combined with pulmonary vein isolation (PVI) has proven effective for persistent atrial fibrillation (AF). However, when performing PWI, creating transmural lesions with subendocardial ablation is sometimes difficult. Endocardial unipolar voltage amplitude had a higher sensitivity than bipolar voltage mapping for identifying intramural viable myocardium in the atria. In this study, we aimed to retrospectively investigate the correlation between the residual potential in the posterior wall (PW) following PWI for persistent AF and atrial arrhythmia recurrence using endocardial unipolar voltage. METHODS: This was a single-center observational study. Patients who underwent PVI and PWI for persistent AF in the first procedure between March 2018 and December 2021 at the Tokyo Metropolitan Hiroo Hospital were included in this study. The patients were divided into two groups based on the presence of residual unipolar PW potentials after PWI with a cutoff of 1.08 mV and the recurrence of atrial arrhythmias was compared. RESULTS: In total, 109 patients were included in the analysis. Forty-three patients had residual unipolar potentials after PWI and 66 patients had no residual unipolar potentials. The atrial arrhythmia recurrence rate was significantly higher in the group with residual unipolar potential (41.8% vs. 17.9%, p = 0.003). The residual unipolar potential was an independent predictor of recurrence (odds ratio: 4.53; confidence interval: 1.67-12.3, p = 0.003). CONCLUSION: Residual unipolar potential after PWI for persistent AF is associated with recurrent atrial arrhythmias.

Comparison of the efficacy of excimer laser coronary angioplasty for ST-segment elevation myocardial infarction with onset-to-balloon time.

Excimer laser coronary angioplasty (ELCA) vaporizes plaques and thrombi, provides better microcirculation, and reduces peripheral embolism when treating acute coronary syndrome. Studies on the efficacy of ELCA for long onset-to-balloon time ST-segment elevation myocardial infarction (STEMI) are limited. Thus, we aimed to examine the efficacy of ELCA for STEMI using the onset-to-balloon time (OBT). A total of 319 patients with STEMI who underwent percutaneous coronary intervention from 2009 to 2012 and from 2015 to 2019 were enrolled. Patients who underwent PCI in 2009-2012 were considered the conventional group, and those treated with ELCA in 2015-2019 were considered the ELCA group. Patients were stratified by OBT. The endpoints were the final thrombolysis in myocardial infarction (TIMI) grade, myocardial blush grade (MBG), and slow-flow or no-reflow phenomenon during the procedure. The ELCA group had 167 patients, and the conventional group had 123. There was no significant difference in achieving final TIMI 3 between the groups. The acquisition rate of final MBG 3 was significantly higher in the ELCA than in the conventional group (79.6% vs. 65.9%; P = 0.01). There was a significant difference between the groups with OBT 12-72 h (82.1% vs. 56.0%; P = 0.031). The slow- or no-reflow incidence during the procedure was significantly lower in the ELCA than in the conventional group with OBT 12-72 h (17.8% vs. 52.2%; P = 0.019). ELCA improves the MBG and reduces intraoperative slow- or no-reflow phenomenon in patients with STEMI, 12-72 h after onset. ELCA will be useful in preventing peripheral embolism in patients with long onset-to-balloon time STEMI.

Relationship between coronary blood flow and improvement of cardiac function after catheter ablation for persistent atrial fibrillation.

BACKGROUND: The relationship between coronary blood flow during atrial fibrillation (AF) and improvement of cardiac function after catheter ablation (CA) for persistent AF (PeAF) is not prominent; this study was conducted to evaluate this relationship. METHODS: This was a retrospective case-control study. Eighty-five patients with PeAF (resting heart rate < 100 bpm) and heart failure with reduced ejection fraction (left ventricular ejection fraction (LVEF) < 40%) who had undergone coronary angiography within 1 week before CA were included. All patients could maintain a sinus rhythm for > 6 months after CA. The primary outcome was improvement of cardiac function with an LVEF cutoff value of > 50% during sinus rhythm 6 months after CA. RESULTS: In the LVEF improvement group (N = 57), patients were younger, with a higher baseline diastolic blood pressure and lower baseline brain natriuretic peptide level than the no LVEF improvement group (N = 28). Heart rate at baseline and 6 months after CA and AF duration did not differ between the two groups. Thrombolysis in myocardial infarction frame count parameters was significantly higher in the LVEF improvement (P < 0.001) than in the no LVEF improvement group. Multivariate logistic regression analysis revealed mean thrombolysis in myocardial infarction frame count as an independent factor for LVEF improvement (odds ratio, 1.72 (95% confidence interval 1.17-2.54); P = 0.006). CONCLUSION: Coronary blood flow in patients with PeAF is strongly associated with improved left ventricular systolic function after the restoration of sinus rhythm by CA for PeAF and heart failure with reduced ejection fraction.

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.

A case report of paroxysmal atrial fibrillation in three pulmonary veins presenting a common trunk.

Background: The pulmonary vein (PV) variant is present in 23-38% of patients who undergo atrial fibrillation ablation, and the common inferior PV (CIPV) variant is a rare PV variant that has been reported in 0.9-1.5% of patients. The arrhythmogenicity of the common trunk of the CIPV is unknown. Case summary: A 77-year-old woman underwent catheter ablation for paroxysmal atrial fibrillation (AF). Preoperative computed tomography revealed a common trunk from which the bilateral inferior PVs and a left superior PV originated. The voltage map of the left atrium (LA) showed three PVs stemming from a common trunk. There was a low-voltage area bounded by the common trunk entrance. An isolation line was created to connect the right superior PV and the common trunk. Twelve months later, AF recurred. The voltage map in second session showed residual irregular potentials at the boundary between the common trunk and the LA, and posterior wall isolation was performed. Postoperatively, the patient maintained sinus rhythm with no antiarrhythmic drugs during the 12-month follow-up period. Discussion: The CIPV is likely to predict the AF recurrence, even if preoperative voltage mapping shows a low voltage area. Substrate modification should be performed on abnormal potentials at the entrance of the common trunk, even though no potential is detected in the PVs or their antrum.

Long-term outcome of ventricular tachycardia ablation in patients who did not undergo programmed electrical stimulation after ablation.

BACKGROUND: Ventricular arrhythmia inducibility is one of the ideal endpoints of ventricular tachycardia (VT) ablation. However, it may be challenging to implement programmed electrical stimulation (PES) at the end of the procedure under several circumstances. The long-term outcome of patients who did not undergo PES after VT ablation remains largely unknown. PURPOSE: To investigate the details and long-term outcome of VT ablation in patients who did not undergo PES at the end of the ablation procedure. METHODS: Among 183 VT ablation procedures in patients with structural heart disease who underwent VT ablation using an irrigated catheter, we enrolled those who did not undergo PES after VT ablation. VT ablation strategy involved targeting clinical VT plus pacemap-guided substrate ablation if inducible. When VT was not inducible, substrate-based ablation was performed. The primary endpoint was VT recurrence. RESULTS: In 58 procedures, post-ablation VT inducibility was not assessed. The causes were non-inducibility of sustained VT before ablation (27/58, 46.6%), long procedure time (27.6%, mean 392 min), complications (10.3%), intolerant hemodynamic state (10.3%), and inaccessible or unsafe target (6.9%). With regard to the primary endpoint, 23 recurrences (39.7%) were observed during a mean follow-up period of 2.5 years. Patients with non-inducibility before ablation showed less VT recurrences (4/27, 14.8%) during follow-up than patients with other causes of untested PES after ablation (19/31, 61.2%) (Log-rank < 0.001). CONCLUSIONS: VT recurrence was not observed in approximately 60% of the patients who did not undergo PES at the end of the ablation procedure. PES after VT ablation may be not needed among patients with pre-ablation non-inducibility.

Optimal local impedance parameters for successful pulmonary vein isolation in patients with atrial fibrillation.

INTRODUCTION: Local impedance (LI) parameters of IntellaNav STABLEPOINT for successful pulmonary vein isolation (PVI) of atrial fibrillation (AF) remain unclear. The purpose of this study was to seek LI data achieving successful PVI. METHODS: Consecutive AF patients who underwent catheter ablation with STABLEPOINT were prospectively enrolled in two centers. PVI was performed under a constant 35-or 40-watt power, 20-s duration, and >5-g contact force. The operators were blinded to the LI data. The characteristics of all ablation points with/without conduction gaps (Unsuccess or Success tags) after the first-attempt PVI were evaluated for the right/left PVs and anterior/posterior wall (RPV/LPV and AW/PW, respectively), and cutoff values of LI data were calculated for successful lesion formation. RESULTS: A total of 5257 ablation points in 102 patients (65 [58-72] years old, 65.7% male) were evaluated. The LI drop values were higher in the Success tags than Unsuccess tags on the LPV-AW and RPV-AW/PW (p < .001), except for the LPV-PW (p = .105). The %LI drop values (LI drop/initial LI) were higher for the Success tags in all areas (15.8 [12.2%-19.6%] vs. 11.6 [9.7%-15.6%] in LPV-AW: p < .001, 15.0 [11.5%-19.3%] vs. 11.4 [8.7%-17.3%] in LPV-PW: p = .035, 15.3 [11.5%-19.4%] vs. 9.9 [8.1%-13.7%] in RPV-AW: p < .001, and 13.3 [10.1%-17.4%] vs. 8.1 [6.3%-9.5%] in RPV-PW, p < .001). The LI drop and %LI drop cutoff values were 20.0 ohms and 11.6%, respectively. CONCLUSIONS: An insufficient LI drop with STABLEPOINT was associated with a gap formation during PVI, and the best cutoff values for the LI drop and %LI drop were 20.0 ohms and 11.6%, respectively.

Benefits of excimer laser coronary angioplasty over thrombus aspiration therapy for patients with acute coronary syndrome and thrombolysis in myocardial infarction flow grade 0.

In primary percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS), the presence of a thrombus or unstable plaque can cause microvascular obstructions, which may increase infarct size and reduce survival. Excimer laser coronary angioplasty (ELCA) is a unique revascularization technique that can vaporize plaques and thrombi. However, to date, only few reports indicate the efficacy of ELCA for ACS. We retrospectively analyzed 113 consecutive ACS patients who underwent PCI with either ELCA or manual thrombus aspiration therapy (TA) before balloon angioplasty or stenting and who had a Thrombolysis in Myocardial Infarction flow (TIMI) grade 0 on the first contrast injection within 24 h of onset at our hospital from March 2011 to March 2020. Patients were divided into two groups by the procedure used: ELCA (N = 48) and TA (N = 50). Door-to-reperfusion time was significantly shorter in the ELCA group than TA group (89.2 ± 6.7 vs. 137.9 ± 12.3 min, respectively; P < 0.01). There was also a significant difference in peak creatine kinase-myocardial band between the ELCA and TA groups (242 ± 25 vs. 384 ± 63 IU/L, respectively; P = 0.04). Although there was no difference in myocardial blush grade (MBG) before treatment, the MBG after treatment was higher in the ELCA group (P < 0.01). In-hospital major adverse cardiac events (MACE) were also significantly fewer in the ELCA group than in the TA group (8% vs. 20%, P = 0.045). ELCA for TIMI grade 0 ACS may shorten reperfusion time, improve the MBG score, and reduce MACE when compared to TA.

Left atrial macroreentrant tachycardia via Bachmann bundle revealed by epicardial mapping.

Although it is common for bi-atrial tachycardia (AT) circuits to include the Bachmann bundle, there are few reports of its role in left AT circuits. A 77-year-old man was admitted for recurrent AT with a cycle length of 425 ms. The endocardial and epicardial activation map revealed an AT circuit located in the left atrial anterior wall and transverse pericardial sinus, showing a centrifugal pattern stemming from the left atrial appendage. After radiofrequency ablation, AT was no longer induced. This case suggests that the Bachmann bundle may be part of the left AT circuit.