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Background: Different types of recurrent atrial tachycardia (AT) after Cox-maze procedures have been reported, whereas biatrial tachycardia (BiAT) has not been systematically analyzed., Objective: In this study, we retrospectively investigated the electrophysiologic characteristics of BiAT after Cox-maze procedures by use of an ultrahigh-density mapping system., Methods: Of a consecutive 76 patients who underwent catheter ablation of AT after Cox-maze procedures, 12 BiATs were identified. High-density activation mapping was performed in both the left atrium and right atrium in combination with entrainment pacing to confirm the circuit., Results: We classified these BiATs into 2 groups. In group 1 (7 patients), the bidirectional block of maze linear lesions to prevent the macroreentrant AT was achieved; the posterior interatrial connections were involved in the circuit. In group 2 (5 patients), the bidirectional block of maze linear lesions was not blocked, and the most common gap was located at the end of the linear lesion near the annulus. In group 1, all the ATs were terminated by targeting the corresponding left atrium end of the posterior interatrial connections. In group 2, the ATs were terminated by targeting the gap near the annulus., Conclusion: The optimal ablation strategy for BiATs after the maze procedure should be based on detailed demonstration of the circuit by high-density mapping., Competing Interests: Disclosures The authors have no conflicts of interest to disclose., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Mapping and ablation of atrial tachycardia (AT) in patients who have had prior cardiac surgery can be a challenge for clinical electrophysiologists. High density mapping (HDM) technology has been widely used in these patients because it provides a better characterization of the substrate and the mechanisms with an unprecedented high resolution. In this review, we summarize how the latest HDM technologies can reveal the mechanism of AT in different types of patients post-cardiac surgery and guide a specifically tailored ablation strategy., (© 2023 Wiley Periodicals LLC.)

Background: Endocardial ablation is effective for most focal atrial tachycardias (FATs). In rare circumstances, the FAT can originate from the epicardial side of the atrium., Objective: In the present study, we retrospectively assessed the percutaneous approach for epicardial ablation of FAT when standard endocardial ablation had failed., Methods: Among a consecutive 186 patients undergoing ablation for 198 FATs, epicardial mapping and ablation via a percutaneous subxiphoid approach were attempted in 10 patients because of failed endocardial ablation., Results: In 3 cases, the origin of FAT was at the epicardial side of the junction of the right atrial appendage and superior vena cava. In 3 cases, the origin of FAT was located in the epicardial region of the left atrial insertion of Bachmann bundle. In 2 cases, the FAT originated from the epicardial side of the right atrial free wall. In 1 case, the FAT was successfully ablated from the epicardial side of the right atrial appendage, and in the remaining case, the origin of FAT was located in the epicardial region of the vein of Marshall. All FATs were successfully eliminated by ablation at the epicardial earliest activation site., Conclusion: Epicardial mapping and ablation can be considered as an effective and safe option for FAT resistant to endocardial ablation., (Copyright © 2022 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Purpose: Idiopathic epicardial ventricular arrhythmias (VAs) are clustered in the areas of the summit and crux. This study was to report a group of idiopathic epicardial VAs remote from the summit and crux areas., Methods: In total, 9 patients (6 males, mean age 32 ± 13 years) were enrolled. The locations were identified by epicardial mapping and ablation. The electrocardiographic and electrophysiological characteristics were compared to those of 9 patients who had VAs ablated at the opposite endocardial site., Results: VAs were identified at the epicardium, with 4 patients had VAs located at the inferior wall, one at the anterior wall, one at the apex and 3 patients had VAs at the lateral wall. A "QS" type at the location-related leads was the only identified surface electrocardiogram indication suggesting epicardial origin (compared to that of the controls, 100% vs 0%, p<0.001). Endocardial and epicardial mapping revealed pre-maturities of -11 ± 4 ms and -25 ± 8 ms, respectively (VS. -28 ± 8 ms revealed by endocardial mapping in control patients, p<0.001 and p=0.389, respectively). All of the study cases demonstrated an "rS" pattern in the endocardial unipolar electrogram. Acute and long-term successful ablation (a median of 11 months of follow-up) was achieved in all patients without complications., Conclusions: A distinct group of idiopathic VAs remote from the summit and crux areas warranting ablation by a subxiphoid approach were identified. Morphological ECG features of a "QS" type among the location-related grouped leads combined with the mapping findings helped in the identification of the epicardial site of origin., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Premature ventricular complexes (PVCs) with narrow QRS duration, inferior frontal plane QRS axis, and right bundle branch block (RBBB) pattern generally originate from the proximal segment of the left anterior fascicle (LAF)., Objective: The purpose of this study was to investigate the exact origin of this category of PVCs., Methods: Twenty-two patients with assumed proximal LAF-PVCs were enrolled in the study. Detailed mapping of fascicular potentials (FPs) was performed during sinus rhythm (SR) and PVCs., Results: During SR, a cluster of FPs could be found at the most superior portion of the left ventricle (LV). These FPs represented the terminal end of a discrete branch of the left fascicular system, which we named the "retro-aortic root branch" (RARB). The shortest distance between the proximal LAF and the terminal end of the RARB was 13.5 ± 4.2 mm. The earliest activation site (EAS) of PVCs in all patients were confirmed at the terminal end of the RARB, where the FP-V interval was 35.1 ± 4.3 ms during PVCs. The shortest distance from the right coronary cusp (RCC) to the EAS was 5.3 ± 3.5 mm. PVCs could be eliminated by ablation from the RCC in 45.5% (10/22) cases, in the remaining cases, ablation at the EAS in the LV endocardium successfully abolished PVCs., Conclusion: The terminal end of the retro-aortic root branch was the actual origin site for PVCs with inferior frontal plane axis, RBBB pattern and narrow QRS duration. Ablation in the RCC or at the EAS in the LV could both eliminate PVCs safely with high efficacy., (Copyright © 2022 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Catheter ablation of right atrial (RA) tachycardia in patients who have extensive spontaneous RA scarring is challenging due to the complex substrate and the potential for multiple inducible atrial tachycardias (ATs)., Methods: Eighteen patients with scar-related RA AT and no prior cardiac surgery were enrolled. A total of 52 different ATs (mean 3.2 ± 1.5 ATs per patient) were observed. We endeavored to complete activation maps for 45 ATs., Results: By analyzing activation maps, we classified ATs into six categories. The discrepant location and extension of ESAs were associated with different AT mechanisms., Conclusions: Multiple scar-related RA ATs were observed in patients without previous cardiac surgery. The detailed activation patterns of these ATs could be clearly demonstrated by using an ultra-high-density mapping system., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Clinical studies have suggested that there is a significant correlation between left ventricular (LV) false tendon and premature ventricular complexes (PVCs)., Objective: This study aimed to investigate the electrophysiological characteristics and the outcome of radiofrequency catheter ablation (RFCA) for this category of PVCs., Methods: From a total of 2284 patients with idiopathic PVCs who underwent catheter ablation at 6 institutions in China, intracardiac echocardiography (ICE) was used during the procedure in 346 cases; 10 patients (2.9%) with PVCs associated with false tendon were retrospectively reviewed and enrolled in the present study. Activation mapping and pace mapping were performed to localize the origin of PVCs. ICE was used in all patients. If the false tendon was directly visualized and identified, we attempted to identify the distinct relationship with the PVC origin., Results: The PVCs were successfully eliminated by ablation in all patients. The target sites were confirmed to be related to false tendon. The origin of PVCs was located at the attachment of the false tendon to the papillary muscle, LV septum, or LV apex. At the target site, high-frequency Purkinje potentials were observed preceding local ventricular activation in 7 patients., Conclusion: LV false tendon can be associated with PVCs, which can be cured by RFCA. An ICE-guided electroanatomical approach should be considered to improve the safety and feasibility of this procedure., (Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Macroreentrant biatrial tachycardia (BiAT) associated with interatrial septal incisions after mitral valve (MV) surgery has been rarely reported., Objective: The purpose of this study was to assess the mapping and ablation strategy of this special category of atrial tachycardia (AT)., Methods: We identified 10 BiATs from a total of 84 ATs after MV surgery performed at 3 institutions. Activation maps for both the right atrium (RA) and left atrium (LA) were obtained using an ultrahigh-density mapping system. We also performed entrainment pacing from multiple LA and RA site within the speculative circuit., Results: By analyzing activation and propagation maps of both atria, we classified the circuit into 3 distinct types. In all types, posteroinferior interatrial connections act as a critical limb that, combined with other interatrial connections (Bachmann bundle, fossa ovalis, and coronary sinus ostium in 3 types, respectively), complete the circuit of BiATs. Most ATs (8/10) were terminated targeting the RA and LA end of posteroinferior interatrial connection sites., Conclusion: Ultrahigh-density mapping provides a detailed description of the macroreentrant circuit of BiAT associated with interatrial septal incisions. Posteroinferior interatrial connections were essential for the circuit and should be the preferred target for ablation., (Copyright © 2020 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: The ablation therapy for persistent atrial fibrillation (PerAF) is still a challenge due to the high recurrence rate. This study was aimed to investigate the value of extensive linear ablation with contact force sensing techniques for PerAF., Methods: A total of 214 patients with PerAF were enrolled in five centers. The patients were randomly assigned to Group I (PVI + LA roof line+ LA anterior wall line) and Group II (PVI + LA roof line), mitral valve isthmus lines were added in both groups if the atrial fibrillation (AF) could not be terminated after all approaches above., Results: Acute success rate of AF termination during the ablation procedure in Group I was significantly higher than Group II (P = 0.028). Two-years follow-up showed no significant difference in the sinus rhythm maintenance rate between the two groups (63.4% in group I vs. 57.2% in group II, P = 0.218). More patients in Group I recurred as organized atrial tachycardia (AT) and can be precisely mapped during repeat ablation procedures (15 vs. 2, P = 0.001). The Kaplan-Meier estimates of AF/AT-free survival after repeat ablation procedures were 76.2% in Group I and 47.1% in Group II (P = 0.039)., Conclusions: Extensive linear ablation with contact force monitoring did not improve the long-term outcomes for PerAF patients. Repeat ablation procedure showed a possible higher chance of sinus rhythm restoration during follow-up., (Copyright © 2020. Published by Elsevier B.V.)

Background: Idiopathic premature ventricular complexes (PVCs) that originate from the left fascicular system have rarely been reported., Objective: The present study aimed to investigate the electrophysiological characteristics and the ablation strategy for this category of PVCs., Methods: Of 648 patients with idiopathic PVCs, 27 were enrolled in this study. All the PVCs presented with a relatively narrow QRS complex and right bundle branch block morphology. The mean QRS duration was 117.4 ± 8.6 ms. Radiofrequency catheter ablation was applied at the site recording the earliest fascicular potential (FP)., Results: The origin of PVCs was as follows: 15 originating from the left anterior fascicle, 7 originating from the left posterior fascicle, 2 originating from the left middle fascicle, and 3 originating from the common trunk of the left bundle branch. The earliest local FP preceded the onset of the QRS complex by 32.7 ± 6.4 ms. The immediate ablation success rate was 100%. Three patients had recurrent PVCs during follow-up. The total success rate of a single procedure was 88.9%., Conclusion: Ablation of PVCs originating from the left fascicular system guided by an earliest presystolic FP was found to be safe and effective., (Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Right ventricular outflow tract (RVOT) ventricular arrhythmias (VAs) may originate from the pulmonary sinus cusps (PSCs) far more frequently than previously recognized., Objective: The purpose of this study was to assess whether mapping and ablation in PSCs might be an appropriate first-choice treatment in unselected patients with idiopathic RVOT VAs., Methods: Ninety consecutive patients with VAs of RVOT-type origin were prospectively enrolled at our institution between August 2015 and September 2016. Pulmonary valve (PV) and PSCs were precisely localized by pulmonary arteriography. Activation and pace-mapping were performed in the PSCs and RVOT region below the PV, and ablation was preferentially performed in PSCs., Results: In 81 patients (90%), earliest activation of VAs was found in PSCs, and ablation resulted in elimination of VAs without any additional ablation in the RVOT region underneath the PV. The best pace-map was obtained at successful ablation sites in PSCs in 96.3% of patients. In the remaining 9 patients, final successful ablation sites were in the aortic coronary cusps in 5 and at the lowest and most posterior part of the RVOT in 4. During mean follow-up of 15.2 ± 9.5 months, single procedural success rate was 96.7%., Conclusion: In this single-center, prospective study, a strategy based on PSC mapping and ablation eliminated 90% (81/90) of unselected idiopathic RVOT-type VAs with favorable mid-term effectiveness., (Copyright © 2017. Published by Elsevier Inc.)

Introduction: Adenosine triphosphate (ATP) has been used to provoke dormant pulmonary vein (PV) conduction after circumferential PV isolation (CPVI). However, there have been no systematic studies examining the incidence and the mechanism of ATP-induced atrial fibrillation (AF) following CPVI in paroxysmal AF. In this study, we explore the mechanism of ATP-induced AF and assess the feasibility of eliminating this response by additional radiofrequency (RF) ablation., Methods and Results: A total of 300 consecutive patients with paroxysmal AF underwent CPVI. After all PVs were isolated, intravenous ATP (40 mg) was administered during an intravenous isoproterenol (ISP) infusion (5 μg/min). AF was reproducibly induced by ATP in 39 patients. Non-PV foci were confirmed and located in 29 of these patients at the onset of AF, including 27 foci in the superior vena cava (SVC), 1 focus in the crista terminalis, and 1 focus near the antrum of the PV. In all these cases, ATP-induced AF was eliminated after the non-PV foci were successfully ablated. For the other 10 patients, the foci triggering AF could not be confirmed or located due to the transient effect of ATP, thus no further ablation was performed. After a mean follow-up period of 18.7 ± 6.4 (8-24) months, the success rate in the ATP-induced AF group was not significantly different compared with the conventional treatment group who did not exhibit ATP-induced AF (76.9% vs 67.3%; P = 0.25). But in the subgroup of which the ATP-induced AF could be eliminated by additional RF ablation, the success rate was significantly higher than the non-ATP inducible group (86.2% vs 67.3%; P = 0.04)., Conclusions: A large proportion of the ATP-induced AF post CPVI were initiated by rapid firing in the SVC. Eliminating this response by additional ablation may have an influence on clinical results of paroxysmal AF ablation., (© 2014 Wiley Periodicals, Inc.)

Introduction: Descriptions for left atrial macroreentry tachycardia (LAMRT) in patients without obvious structural heart disease or previous surgery or catheter radiofrequency (RF) ablation have been sparse., Methods and Results: Ten of 226 patients (7 women, mean age 57 ± 14) with LAMRT underwent electroanatomic mapping and catheter ablation. None of the 10 patients had structural heart disease or history of previous surgery or catheter ablation. In all patients, the reentry circuits were located within a large low-voltage (bipolar voltage ≤ 0.5 mV) area in left atrium (LA), which contained 2.6 ± 1.2 electrically silent areas (ESAs) and/or lines of double potentials (LDPs). The tachycardia circuit propagated through a narrow isthmus (<5 mm width) bounded by ESAs/LDPs and adjacent anatomical barriers (e.g., mitral annulus). In these isthmus, low amplitude (0.21 ± 0.05 mV), long-duration (123 ± 14 milliseconds) fractionated electrograms were found in 8 tachycardias, accounting for 43 ± 5% of the tachycardia cycle length. In 2 other tachycardias without fractionated electrograms, the electrogram amplitude in the isthmus was extremely low (<0.1 mV). RF energy was delivered at the isthmuses and terminated all 10 tachycardias. After ablation, the original LAMRT was not inducible in all patients. During follow-up (mean 14 ± 10 months), 2 patients developed recurrence of ATs and were successfully ablated., Conclusion: Extensive scarring of the LA formed arrhythmogenic substrates of LAMRT in this group of patients. Ablation targeting these narrow, slow conduction zones eliminated atrial tachycardia in all patients., (© 2012 Wiley Periodicals, Inc.)

Background: For patients with persistent atrial fibrillation (AF), whether linear ablation should be performed remains controversial, and the efficacy and safety for ablation index (AI)-guided high-energy linear ablation of mitral isthmus (MI) and left atrial (LA) posterior box isolation is still unclear. The aims of this study were to assess the feasibility and clinical success rate of pulmonary veins isolation (PVI) combined with linear ablation of LA roof and posterior inferior (posterior wall isolation) and MI compare with the PVI-alone method in patients of persistent AF. Methods and results: 362 consecutive persistent AF patients were enrolled from two electrophysiology centers. A total of 200 cases were in PVI-plus group and 162 cases were in PVI-alone group. The PVI-alone group received wide circumferential isolation of both ipsilateral pulmonary veins. PVI combined with linear ablation of left atrial posterior wall isolation (LAPWI)and MI were performed in the PVI-plus group. The primary study end point was the first recurrence of an atrial arrhythmia. After 24 months, freedom from the primary endpoint was achieved in 73.5% of the patients in the PVI-plus group and 62.5% in the PVI-alone group (hazard ratio = 0.62, 95% confidence interval: 0.43–0.91, log rank p = 0.012). The procedure-related complication rates were 2.5% in PVI-plus group and 1.9% in PVI-alone group (p = 0.808). Conclusion: In this study, the ablation strategy of ablation (PVI plus linear ablation of mitral isthmus and posterior box isolation) was feasible and safe for persistent AF patients. Compared with the PVI-alone method, it improved outcomes in patients with persistent AF. [ABSTRACT FROM AUTHOR]

Consequences of Left Atrial Anterior Wall Linear Ablation Objective As an alternative to the mitral isthmus line (MIL), the left atrial anterior wall line (LAAWL) is effective for the treatment of perimitral flutter. This study evaluated the electrophysiologic and clinical outcomes of LAAWL versus MIL in patients with persistent atrial fibrillation (AF). Methods Two hundred patients with persistent AF were evenly randomized to the LAAWL and MIL groups. After confirming bidirectional block of the line, left atrial appendage (LAA) activation time and LA propagation pattern were assessed during sinus rhythm (SR). Transthoracic and transesophageal echocardiography (TTE and TEE) were performed at 12 months after ablation in patients who remained in stable SR. Results In the 74 patients with LAAWL conduction block relative to the 79 with MIL conduction block, LA propagation contour was markedly changed with delayed LAA potential (longer P-wave onset-to-LAA potential interval: 151.7 ± 19.5 vs. 67.8 ± 18.3 milliseconds, P < 0.001); TTE peak A velocity was lower and LAA emptying wave was delayed in the LAAWL group compared with the MIL group; spontaneous echo contrast (SEC) detected in the LAAWL group was significantly higher than that in the MIL group (15.8% vs. 1.6%, p = 0.0004). During a mean follow-up period of 31.8 ± 9.4 (22-57) months, there were 5 cases of stroke in the LAAWL group, which was significantly different from the MIL group (5% vs. 0%, P = 0.047). Conclusions Complete linear lesions transecting the anterior LA were associated with a significant change in the SR propagation pattern with late activation of LAA. This might result in an increased risk of long-term thrombo-embolism events. [ABSTRACT FROM AUTHOR]

Background: Atrial tachycardia (AT) with cycle length (CL) alternans is a rare phenomenon. We aimed to identify the characteristics and precise mechanism of this special category of ATs by using an ultrahigh density mapping system.Methods: We identified 7 ATs with alternating CL in a total of 478 ATs from 2 institutions mapped with an ultrahigh density mapping system. Activation maps were performed for long CL (289±35 ms; mapping points, 21 520±11 103) and short CL (251±18 ms; mapping points,17 594±8059) separately.Results: We classified ATs with CL alternans into 2 types. Type 1: There existed 2 potential loops with different routes. CL alternans resulted from an intermittently 2:1 conducting block within the channel of the smaller loop. Type 2: CL alternans resulted from different conduction velocity through 2 closely spaced gaps within preexisting linear lesions. Catheter ablation successfully terminated all the 7 ATs.Conclusions: Ultrahigh density mapping provides an opportunity to delineate the precise mechanism of AT with CL alternans. Intermittent conduction block or slowing of a channel was essential for the maintenance of AT. [ABSTRACT FROM AUTHOR]