Persistent left superior vena cava isolation in patients with atrial fibrillation: Selective or empirical?

BACKGROUND: Persistent left superior vena cava (PLSVC) is the most prevalent form of thoracic venous abnormality and can serve as a significant arrhythmogenic source in atrial fibrillation (AF). METHODS AND RESULTS: Among the 3950 patients who underwent radiofrequency ablation for AF between September 2014 to April 2020, 17 patients (mean age 59.4 ± 8.0 years, 64.7% male) with PLSVC were identified. Among them, nine patients (52.9%) had a prior history of pulmonary vein isolation (PVI) alone. Eight out of nine patients who experienced AF recurrence underwent PLSVC isolation with or without pulmonary vein (PV) reconnection. For the remaining eight patients (47.1%), PVI plus PLSVC isolation were performed during the index procedure. Ectopy originating from PLSVC was documented in 11 patients (64.7%) and successful PLSVC isolation was achieved in 16 patients (94.1%). After a median follow-up of 28.3 months, freedom from AF/ atrial tachycardia (AT) was observed in 13 patients (76.5%). CONCLUSION: Empirical PLSVC isolation beyond PVI appears to be a feasible and safe strategy to prevent AF recurrence in patients with concomitant PLSVC.

Scar-related atrial macroreentries: Different arrhymogenic basis generates different reentry type.

BACKGROUND: Catheter ablation is an established therapeutic strategy to treat scar-related macroreentry atrial tachycardia (MAT). However, the scar properties and arrhythmogenicity and the reentry type have not been clearly defined. METHODS AND RESULTS: A total of 122 patients with scar-related MAT were enrolled in this study. The atrial scars were classified into two categories: spontaneous scars (Group A: n = 28) and iatrogenic scars (Group B: n = 94). According to the relationship between scar location and the reentry circuit, MAT was described as scar pro-flutter MAT, scar-dependent MAT, and scar-mediated MAT. The reentry type of MAT was significantly different between Groups A and B: pro-flutter (40.5% vs. 62.0%, p = 0.02), scar-dependent AT (40.5% vs. 13.0%, p < 0.001), and scar-mediated AT (19.0% vs. 25.0%, p = 0.42). After a median follow-up of 25 months, 21 patients with AT recurrence were observed. Compared with the spontaneous group, there was a lower recurrence rate of MAT in the iatrogenic group (28.6% vs. 10.6%, p = 0.03). CONCLUSION: Scar-related MAT has three reentry types, and the proportion of each type varies with the scar properties and its arrhythmogenic basis. Optimization of the ablation strategy based on the scar properties to improve the long-term outcome of catheter ablation of MAT is necessary.

Chinese expert consensus on the construction of the fluoroless cardiac electrophysiology laboratory and related techniques.

Transcatheter radiofrequency ablation has been widely introduced for the treatment of tachyarrhythmias. The demand for catheter ablation continues to grow rapidly as the level of recommendation for catheter ablation. Traditional catheter ablation is performed under the guidance of X-rays. X-rays can help display the heart contour and catheter position, but the radiobiological effects caused by ionizing radiation and the occupational injuries worn caused by medical staff wearing heavy protective equipment cannot be ignored. Three-dimensional mapping system and intracardiac echocardiography can provide detailed anatomical and electrical information during cardiac electrophysiological study and ablation procedure, and can also greatly reduce or avoid the use of X-rays. In recent years, fluoroless catheter ablation technique has been well demonstrated for most arrhythmic diseases. Several centers have reported performing procedures in a purposefully designed fluoroless electrophysiology catheterization laboratory (EP Lab) without fixed digital subtraction angiography equipment. In view of the lack of relevant standardized configurations and operating procedures, this expert task force has written this consensus statement in combination with relevant research and experience from China and abroad, with the aim of providing guidance for hospitals (institutions) and physicians intending to build a fluoroless cardiac EP Lab, implement relevant technologies, promote the standardized construction of the fluoroless cardiac EP Lab.

Bipolar catheter ablation strategies for outflow tract ventricular arrhythmias refractory to unipolar ablation.

INTRODUCTION: Conventional unipolar catheter ablation (UA) is generally effective for the treatment of outflow tract ventricular arrhythmias (OT-VAs). However, deep foci refractory to UA remains a clinical challenge. The present study evaluated the efficacy and safety of bipolar ablation (BA) in the treatment of OT-VAs refractory to UA. METHODS: A total of 1022 consecutive patients with antiarrhythmic drugs resistant OT-VAs were screened for inclusion in this study, from 1643 VAs cases who underwent catheter ablation in two centers from October 2014 to May 2019. BA was performed after failed sequential UA. The pair of catheters used for BA was positioned on opposing surfaces of the earliest activation (EA) sites or on adjacent anatomical structures. RESULTS: Twelve patients (seven males, mean age 33.3 ± 16.2 years) who met the inclusion criteria were recruited: one patient suffered sustained monomorphic ventricular tachycardia (VT), six patients had frequent premature ventricular contractions (PVCs), and nonsustained VT (NSVT), and five patients had PVCs only. The 24-hPVC/NSVT burden was 36.9 ± 21.7%. The mean distance between two ablation catheters during BA was 11.1 ± 4.3 mm (range 6.5-23.9 mm). The "rS" morphology of the unipolar electrogram was recorded simultaneously in both EA regions in seven cases (58.3%). Acute eradication of VAs was obtained in 10 (83.3%) cases. At a median follow-up of 58 months, 10 patients (83.3%) remained free from VAs. CONCLUSION: BA was highly effective and safe for the treatment of OT-VAs refractory to UA.

Strategy for Failed Transvenous Left-Ventricular Lead Placement in Cardiac Resynchronization Therapy: Surrender or Struggle?

INTRODUCTION: For those cardiac resynchronization therapy (CRT) candidates who experience left-ventricular (LV) lead placement failure or underwent concomitant cardiac surgeries, surgical placement of epicardial LV lead guided by electroanatomic mapping may be a promising alternative. METHODS: Electroanatomic mapping was used to guide positioning of the LV lead through a surgical approach. The LV lead was placed at the region with the latest local LV activation and normal voltage, away from the scar. RESULTS: From April 2010 to September 2018, 10 consecutive patients (3 female) underwent surgical epicardial LV lead implantation. Among them, 3 had other surgical indications simultaneously (including 1 CRT non-responder), and 7 had failed transvenous LV lead placement. After CRT, the QRS duration was shortened from 149.3 ± 20.4 ms to 125.1 ± 15.2 ms (p = 0.01). At 6 months, the LV ejection fraction was significantly improved and remained stable in the follow-up (FU) period thereafter (baseline vs. 6 months, 31.0 ± 8.3% vs. 42.2 ± 13.4%, p = 0.006). Other parameters, including the threshold and impedance of the LV lead, were also stable at a mean FU of 755 ± 406 days, and the NYHA functional classification decreased from 2.9 ± 0.7 to 1.8 ± 0.8 (p = 0.002). CONCLUSIONS: Placement of an epicardial LV lead guided by electroanatomic mapping could be used as an adjunctive strategy in patients who were unable or refractory to conventional CRT therapy. This approach could also be applied in patients who had other surgical indications at the same time.

Efficacy of ablation index-guided pulmonary vein isolation in patients with paroxysmal atrial fibrillation.

BACKGROUND: Ablation index (AI) is a novel technology of ablation lesion quality to help improve homogeneity of lesion size and continuity. In this study, we aim to evaluate whether AI-guided PVI improves clinical outcomes compared to CF-guided PVI in patients with paroxysmal AF (PAF). METHODS: Patients undergoing first-time radiofrequency ablation for PAF were randomized in a 2:1 ratio to two groups: AI-guided PVI and CF-guided PVI. In the AI group, AI ≥500 was recommended at the anterior/superior/inferior walls, 350-400 at the posterior wall, and inter-lesion distance ≤4 mm. The primary endpoint is the freedom from atrial arrhythmia recurrence during 12 months follow-up, without antiarrhythmic drug therapy (ADT). The key secondary endpoints include intra-procedural efficiency and peri-procedural complications. RESULTS: Two hundred twenty five patients were randomized (AI group [n = 149] and CF group [n = 76]). First-pass isolation rate in AI group was significantly higher than that in CF group (58.3% vs. 43.4%, p = .035). After a median follow-up of 12.2 months, 154/225 (68.4%) of patients were free from atrial arrhythmia recurrence without ADT, which was higher in AI group compared with CF group, but without significant difference (71.1% vs. 63.2%, p = .253). The incidence of peri-procedural complications is low and without difference between two groups. CONCLUSIONS: AI-guided ablation provided higher acute efficacy than CF-guided ablation in PV isolation for patients with paroxysmal AF. The long-term success rate in AI group was higher than CF group, but did not reach statistical significance.

Surgical ablation supplemented by ethanol injection for ventricular tachycardia refractory to percutaneous ablation.

BACKGROUND: A combination of endocardial and epicardial approaches has improved the overall success rate of ventricular tachycardia (VT) ablation in patients with cardiomyopathy. However, the origins of some VTs are truly intramural or close to coronary arteries, which makes this combined strategy either prone to failure or too risky. OBJECTIVES: This observational study aimed to explore the feasibility and efficacy of direct epicardial ablation combined with intramural ethanol injection via surgical approach for inaccessible intramural VTs or VTs too close to coronary arteries. METHODS: In four canines ventricular lesions produced by direct epicardial injection of ethanol were assessed. Six consecutive patients with recurrent VT refractory to catheter endocardial and epicardial RF ablation and that remained inducible after surgical epicardial mapping and RF ablation were included. Ethanol was injected by needle at the epicardial RF ablation sites. The primary outcome was freedom of sustained VT determined by device interrogation and periodical 24-h holter recordings subsequently. RESULTS: In an animal study, the lesions were homogenous and increased in size with the volume of ethanol injected. In all six patients, ethanol injection at the target sites in the anterior or lateral left ventricle abolished inducible VT. Over a median follow-up of 22 months (range, 6-65), all patients remained free of sustained VT. One patient died of pulmonary infection one year after the procedure. CONCLUSIONS: A hybrid strategy of surgical ablation combined with intramural ethanol injection is feasible and effective in patients with multiple failed percutaneous ablation attempts.

Intraprocedural endpoints to predict durable pulmonary vein isolation: a randomized trial of four post-ablation techniques.

AIMS: The optimal procedural endpoint to achieve permanent pulmonary vein isolation (PVI) during ablation of atrial fibrillation (AF) remains unknown. We aimed to compare the impact of prolonged waiting periods and adenosine triphosphate (ATP) testing after PVI on long-term freedom from AF. METHODS AND RESULTS: In total, 538 patients (median age 61 years, 62% male) undergoing first-time radiofrequency ablation for paroxysmal AF were randomized into four groups: Group 1 [PVI (no testing), n = 121], Group 2 (PVI + 30min waiting phase, n = 151), Group 3 (PVI+ATP, n = 131), and Group 4 (PVI + 30min+ATP, n = 135). The primary endpoint was freedom from AF. Repeat mapping to assess for late pulmonary vein (PV) reconnection was performed in patients who remained AF-free for >3 years (n = 46) and in those who had repeat ablation for AF recurrence (n = 82). During initial procedure, acute PV reconnection was observed in 33%, 26%, and 42% of patients in Groups 2, 3, and 4, respectively. At 36 months, no significant differences in freedom from AF recurrence were observed among all four groups (55%, 61%, 50%, and 62% for Groups 1, 2, 3, and 4, respectively; P = 0.258). Late PV reconnection was commonly observed, with a similar incidence between patients with and without AF recurrence (74% vs. 83%; P = 0.224). CONCLUSION: Although PVI remains the cornerstone for AF ablation, intraprocedural techniques to assess for PV reconnection did not improve long-term success. Patients without AF recurrence after 3 years exhibited similarly high rates of PV reconnection as those that underwent repeat ablation for AF recurrence. The therapeutic mechanisms of AF ablation may not be solely predicated upon durable PVI.

Surgical and percutaneous left atrial appendage intervention: silent cerebral embolism considerations.

OBJECTIVES: Left atrial appendage intervention is an alternative to oral anticoagulation for thromboprophylaxis in atrial fibrillation. The aim of our study was to compare the incidence of silent cerebral embolisms after surgical and percutaneous intervention and to identify the risk factors for procedure-related silent cerebral embolisms after intervention. METHODS: This prospective observational study included consecutive atrial fibrillation patients from 2 independent cohorts (left atrial appendage excision (LAAE) cohort and left atrial appendage occlusion cohort) between September 2018 and December 2020. All patients underwent cerebral magnetic resonance imaging before and after the procedure. Silent cerebral embolism was defined as new focal hyperintense lesions detected only on postprocedural sequence. RESULTS: Thirty-two patients from the LAAE cohort and 42 patients from the occlusion cohort were enrolled. A significantly lower incidence of silent cerebral embolism was observed in the LAAE cohort as compared with occlusion (6.3% vs 54.8%, P < 0.001). In the left atrial appendage occlusion cohort, patients who developed silent cerebral embolism after the procedure had significantly higher CHA2DS2-VASc scores [odds ratio (OR) 2.172; 95% confidence interval (CI) 1.149-4.104; P = 0.017], longer occlusion placement time (OR 1.067; 95% CI 1.018-1.118; P = 0.006) and lower peak activated clotting time level after transseptal puncture (OR 0.976; 95% CI 0.954-0.998; P = 0.035). CONCLUSIONS: The incidence of procedure-related silent cerebral embolism was strikingly lower in patients with LAAE than in patients with occlusion. More cardiovascular comorbidities, longer occlusion placement time and lower activated clotting time level were significantly associated with the development of procedure-related silent cerebral embolism.

Epicardial catheter ablation of idiopathic ventricular arrhythmias originating from uncommon epicardial sites.

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.

The role of noncoronary cusp ablation approach in the treatment of perinodal atrial tachycardias.

BACKGROUND: Ablation in the noncoronary aortic cusp (NCC) potentially has a role in the treatment of perinodal atrial tachycardias (ATs). The objective of the study was to characterize clinical and electrophysiological properties of perinodal ATs between two groups of requiring and not requiring NCC ablation. METHODS: A total of 113 patients with focal ATs who underwent electrophysiologic study and radiofrequency catheter ablation were enrolled in the study. The clinical and electrophysiological characteristics of ATs that need and not need NCC ablation were compared. RESULTS: Totally 20 cases were revealed to have the focal ATs located in the perinodal area. Among them, only five cases (25%) warrant ablation in the NCC, whereas the remainder could be successfully eliminated by ablation from the endocardial right atrium at the perinodal region. There were no clinical and electrophysiological clues observed to have the potential to predict the true original site, including the activation mode, the three-dimensional mapping characteristics of earliest activation site in the right atrium, as well as the time of termination during the ablation in the perinodal area. CONCLUSIONS: Approximately, one-fourth of the perinodal ATs warrant ablation in the NCC. However, no clinical and electrophysiological clues could predict the potential site of the perinodal ATs.