Variant of ventricular outflow tract ventricular arrhythmias requiring ablation from multiple sites: Intramural origin.

BACKGROUND: The optimal site of ablation of idiopathic left ventricular outflow tract (LVOT) ventricular arrhythmias (VAs) is challenging as activation mapping can reveal similar activation times in different anatomical sites, suggesting an intramural origin. OBJECTIVE: We sought to assess whether in patients with intramural VAs and with multiple early activation sites (EASs), sequential ablation of all the early EASs could improve acute and long-term clinical outcomes. METHODS: A total of 116 patients undergoing catheter ablation for symptomatic LVOT VAs were enrolled in this study. Thirty-nine patients (34%) were referred for a redo procedure, whereas the remaining presented for a first procedure. Mapping was performed manually in 86 cases (74%) and with a magnetic robotic system (Niobe, Stereotaxis, St. Louis, MO) in the remainder of the cases. RESULTS: Of the 116 patients, 15 (13%) were found to have multiple sites of equally early activation. In patients with multiple EASs, the mean pre-QRS activation time was significantly less than in patients with a single EASs (-26 ± 3 ms vs -38 ± 6 ms; P < .005). Sequential ablation of all the EASs was possible in 14 patients (93%), resulting in complete arrhythmia suppression. After a mean follow-up of 21 ± 5 months, all patients with successful ablation of all multiple early EASs remained free from clinical VAs. CONCLUSION: Intramural LVOT VAs manifesting with multiple EASs require ablation at all sites to achieve acute and long-term success, particularly if none of the EASs is > -30ms pre-QRS activation time.

Long-term follow-up of patients with paroxysmal atrial fibrillation and severe left atrial scarring: comparison between pulmonary vein antrum isolation only or pulmonary vein isolation combined with either scar homogenization or trigger ablation.

AIMS: Left atrial (LA) scarring, a consequence of cardiac fibrosis is a powerful predictor of procedure-outcome in atrial fibrillation (AF) patients undergoing catheter ablation. We sought to compare the long-term outcome in patients with paroxysmal AF (PAF) and severe LA scarring identified by 3D mapping, undergoing pulmonary vein isolation (PVAI) only or PVAI and the entire scar areas (scar homogenization) or PVAI+ ablation of the non-PV triggers. METHODS AND RESULTS: Totally, 177 consecutive patients with PAF and severe LA scarring were included. Patients underwent PVAI only (n = 45, Group 1), PVAI+ scar homogenization (n = 66, Group 2) or PVAI+ ablation of non-PV triggers (n = 66, Group 3) based on operator's choice. Baseline characteristics were similar across the groups. After first procedure, all patients were followed-up for a minimum of 2 years. The success rate at the end of the follow-up was 18% (8 pts), 21% (14 pts), and 61% (40 pts) in Groups 1, 2, and 3, respectively. Cumulative probability of AF-free survival was significantly higher in Group 3 (overall log-rank P <0.01, pairwise comparison 1 vs. 3 and 2 vs. 3 P < 0.01). During repeat procedures, non-PV triggers were ablated in all. After average 1.5 procedures, the success rates were 28 (62%), 41 (62%), and 56 (85%) in Groups 1, 2, and 3, respectively (log-rank P< 0.001). CONCLUSIONS: In patients with PAF and severe LA scarring, PVAI+ ablation of non-PV triggers is associated with significantly better long-term outcome than PVAI alone or PVAI+ scar homogenization.

Left Atrial Appendage Isolation in Patients With Longstanding Persistent AF Undergoing Catheter Ablation: BELIEF Trial.

BACKGROUND: Longstanding persistent (LSP) atrial fibrillation (AF) is the most challenging type of AF. In addition to pulmonary vein isolation, substrate modification and triggers ablation have been reported to improve freedom from AF in patients with LSPAF. OBJECTIVES: This study sought to assess whether the empirical electrical isolation of the left atrial appendage (LAA) could improve success at follow-up. METHODS: This was an open-label, randomized study assessing the effectiveness of empirical electrical left atrial appendage isolation for the treatment of LSPAF. Patients were randomly assigned to undergo empirical electrical left atrial appendage isolation along with extensive ablation (group 1; n = 85) or extensive ablation alone (group 2; n = 88). Recurrence of atrial arrhythmias was the primary endpoint. Secondary endpoints included cardiac-related hospitalization, all-cause mortality, and stroke at follow-up. RESULTS: Major clinical characteristics were not different between the 2 groups. At 12-month follow-up, 48 (56%) patients in group 1 and 25 (28%) in group 2 were recurrence free after a single procedure (unadjusted hazard ratio [HR] for recurrence with standard ablation: 1.92; 95% confidence interval [CI]: 1.3 to 2.9; log-rank p = 0.001). After adjusting for age, sex, and left atrial size, standard ablation was predictive of recurrence (HR: 2.22; 95% CI: 1.29 to 3.81; p = 0.004). During repeat procedures, empirical electrical left atrial appendage isolation was performed in all patients. After an average of 1.3 procedures, cumulative success at 24-month follow-up was reported in 65 (76%) in group 1 and in 49 (56%) in group 2 (unadjusted HR: 2.24; 95% CI: 1.3 to 3.8; log-rank p = 0.003). CONCLUSIONS: This randomized study showed that both after a single procedure and after redo procedures in patients with LSPAF, empirical electrical isolation of the LAA improved long-term freedom from atrial arrhythmias without increasing complications. (Effect of Empirical Left Atrial Appendage Isolation on Long-term Procedure Outcome in Patients With Persistent or Longstanding Persistent Atrial Fibrillation Undergoing Catheter Ablation [BELIEF]; NCT01362738).

Is transesophageal echocardiogram mandatory in patients undergoing ablation of atrial fibrillation with uninterrupted novel oral anticoagulants? Results from a prospective multicenter registry.

BACKGROUND: Transesophageal echocardiography (TEE) is recommended in patients undergoing atrial fibrillation (AF) ablation, but use of this strategy is variable. OBJECTIVE: To evaluate whether TEE is necessary before AF ablation in patients treated with novel oral anticoagulants (NOACs). METHODS: We performed a prospective multicenter registry of AF patients undergoing radiofrequency catheter ablation on uninterrupted NOACs (apixaban and rivaroxaban). All patients were on NOACs for at least 4 weeks before ablation. Heparin bolus was administered to all patients before transseptal catheterization to maintain a target activated clotting time above 300 seconds. A subset of 86 patients underwent brain diffuse magnetic resonance imaging (dMRI) to detect silent cerebral ischemia (SCI). RESULTS: A total of 970 patients (514 [53%] apixaban patients and 456 [47%] rivaroxaban patients) were enrolled for this study. The mean age was 69.5 ± 9.0 years, with 824 patients (85%) having nonparoxysmal AF, and 636 patients (65.6%) were male. The average CHA2DS2-VASc score was 3.01 ± 1.3 and CHADS2 score was ≥2 in 609 patients (62.8%). Intracardiac echocardiogram ruled out left atrial appendage thrombus in all patients whose left atrial appendage was visualized (692, 71%), and detected "smoke" in 407 patients (42%). SCI at postprocedure dMRI was detected in 2.3% (2/86). One thromboembolic event (transient ischemic attack) (0.10%) with positive dMRI occurred in a patient on uninterrupted rivaroxaban with longstanding persistent AF. CONCLUSION: Our study illustrates that performing AF ablation while on uninterrupted apixaban and rivaroxaban without TEE is feasible and safe. This finding has important clinical and economic relevance.

Importance of non-pulmonary vein triggers ablation to achieve long-term freedom from paroxysmal atrial fibrillation in patients with low ejection fraction.

BACKGROUND: Whether ablation of non-pulmonary vein (PV) triggers after pulmonary vein antrum isolation (PVAI) improves the long-term procedure outcome in patients with paroxysmal atrial fibrillation (PAF) and left ventricular systolic dysfunction is unknown. OBJECTIVE: We sought to evaluate whether a more extensive ablation procedure improves outcomes at follow-up. METHODS: Consecutive patients with PAF refractory to antiarrhythmic drugs presenting for PVAI were prospectively studied. Patients were categorized into 2 groups: patients with left ventricular ejection fraction (LVEF) ≤35% (group I; n = 175) and patients with LVEF ≥50% (group II; n = 545). Patients in group I were further divided according to whether additional ablation of non-PV triggers was performed (group IA; n = 88) or not (group IB; n = 87). Long-term ablation success off antiarrhythmic drugs after a single procedure was analyzed. RESULTS: Patients in group I had more non-PV triggers than did patients in group II (69.1% vs 26.6%; P < .001). During a follow-up of 15.8 ± 4.7 months, fewer patients in group I remained free from recurrences than those in group II (53.7% vs 81.7%; P < .001). Long-term ablation success was higher in group IA than in group IB (75.0% vs 32.2%; P < .001) and similar to that in group II (75.0% vs 81.7%; P = .44). In multivariate analysis, LVEF ≤35% (hazard ratio 1.68; P = .003) and non-PV triggers (hazard ratio 3.12; P < .001) were independent predictors of recurrences. CONCLUSION: In patients with PAF and left ventricular systolic dysfunction, ablation of non-PV triggers in addition to PVAI significantly improves their long-term procedure outcome.

Catheter ablation of atrial fibrillation in patients with mechanical mitral valve: long-term outcome of single procedure of pulmonary vein antrum isolation with or without nonpulmonary vein trigger ablation.

INTRODUCTION: It is unclear whether extended pulmonary vein antrum isolation (PVAI) plus nonpulmonary vein (non-PV) trigger elimination prevents more arrhythmia recurrence than PVAI alone in patients with mechanical mitral valve (MMV) undergoing AF ablation. This study compared the efficacy and long-term outcome of 2 ablation strategies--PVAI alone versus extended PVAI plus non-PV trigger elimination--for the treatment of AF in patients with MMV. METHODS AND RESULTS: One hundred and nine consecutive AF patients with MMV were divided into 2 groups: standard PVAI was performed in group 1 (N = 45); in group 2 (N = 64) PVAI was extended to the LA posterior wall, LA septum, and CS; and all non-PV triggers were eliminated. Patients were followed up for 3 years. At the 12th month, 7 (15.6%) patients in group 1, and 39 (60.9%) patients in group 2 were arrhythmia free (log-rank P < 0.001). Four patients (8.9%; 3 cases of AT and 1 case of AF) from group 1, and 12 patients (18.8%; 9 cases of AT, and 3 cases of AFL) from group 2 experienced very late recurrence. At 36 ± 7 months follow-up, the cumulative recurrence after a single procedure was 42/45 (93.3%) in group 1, and 37/64 (57.8%) in group 2 (log-rank P < 0.001). CONCLUSION: Compared with the standard PVAI alone, a strategy including extended PVAI and non-PV trigger elimination is associated with a higher 12-month and long-term arrhythmia-free survival in patients with MMV undergoing AF ablation. Very late recurrence may occur years after the initial procedure with focal AT as the most common type of recurrent arrhythmia.

Catheter ablation of atrial fibrillation in hypertrophic cardiomyopathy: long-term outcomes and mechanisms of arrhythmia recurrence.

BACKGROUND: Pulmonary vein (PV) antrum isolation in patients with hypertrophic cardiomyopathy and atrial fibrillation (AF) has been reported to have satisfactory results at the mid- and short-term follow-up. We determined the outcomes at the long-term follow-up of PV antrum isolation in these patients. METHODS AND RESULTS: We enrolled 43 patients with hypertrophic cardiomyopathy and AF (28% paroxysmal AF). PV antrum isolation (paroxysmal AF) and posterior wall isolation with complex fractionated atrial electrogram ablation (persistent and longstanding persistent AF) were the end points at the time of the index procedure and for repeat procedures during the first year of follow-up. In case of recurrent arrhythmia >1 year, high-dose isoproterenol challenge was used to disclose non-PV trigger sites. During the first year, the success rate reached 91% (mean of 1.6 procedures). After a median follow-up of 42 months (range, 38-48 months), 49% of the patients remained free from AF/atrial tachycardia. All patients underwent an additional procedure. PV antrum and posterior wall remained isolated in 82% of the cases, and extra-PV triggers were documented in all patients and targeted for ablation. After a median follow-up of 15 months (range, 8-19 months) subsequent to the last procedure, 94% of the patients remained free from AF/atrial tachycardia off antiarrhythmic drugs. CONCLUSIONS: PV isolation in patients with hypertrophic cardiomyopathy is feasible and safe, although is not effective in preventing late (≥1 year) AF recurrences in ≈50% of patients. Non-PV triggers seem to be responsible of late recurrences, which supports the appropriateness of a more extensive ablation beyond PV isolation to improve the long-term arrhythmia-free survival.

Administration of isoproterenol and adenosine to guide supplemental ablation after pulmonary vein antrum isolation.

BACKGROUND: Pulmonary vein antrum isolation (PVAI) remains associated with atrial fibrillation (AF) recurrence. We administered adenosine and isoproterenol (ISP) after PVAI to uncover non-PV atrial triggers and PV reconnection, potentially increasing ablation success rate. METHODS: One hundred and ninety-two consecutive patients with symptomatic AF presenting for PVAI were prospectively studied (group 1). Following PVAI, adenosine (18-24 mg) and ISP (20-30 mcg/min) were administered intravenously. Supplemental ablation was performed in patients with non-PV triggers that induced AF (group 1A). Other subgroups included patients with (group 1B) or without (group 1C) consistent non-PV atrial foci that did not induce AF. A cohort of 196 matched control patients undergoing PVAI without drug challenge was used for comparison (group 2). RESULTS: A total of 132 atrial non-PV foci were revealed (31 inducing AF). The majority of atrial foci were observed with ISP (113/132, 86%). Less than 5% of patients had persistent PV recovery during the drug challenge. During a mean follow-up of 22 ± 8 months, PVAI was successful in 110/192 (57%, group 1) versus 100/196 (52%, group 2), P = 0.038. Furthermore, the success rate was statistically different between group 1A (25/32, 78%), group 1B (28/83, 34%), and group 1C (57/74, 74%), P < 0.001. CONCLUSION: After PVAI, ablation guided by the administration of adenosine and ISP to target non-PV triggers inducing AF increased AF ablation outcomes. Patients with non-PV foci that did not induce AF had no further ablation, with the lowest ablation success rate. This group may likely benefit from further ablation after PVAI.

Endo-epicardial homogenization of the scar versus limited substrate ablation for the treatment of electrical storms in patients with ischemic cardiomyopathy.

OBJECTIVES: This study investigated the impact on recurrences of 2 different substrate approaches for the treatment of these arrhythmias. BACKGROUND: Catheter ablation of electrical storms (ES) for ventricular arrhythmias (VAs) has shown moderate long-term efficacy in patients with ischemic cardiomyopathy. METHODS: Ninety-two consecutive patients (81% male, age 62 ± 13 years) with ischemic cardiomyopathy and ES underwent catheter ablation. Patients were treated either by confining the radiofrequency lesions to the endocardial surface with limited substrate ablation (Group 1, n = 49) or underwent endocardial and epicardial ablation of abnormal potentials within the scar (homogenization of the scar, Group 2, n = 43). Epicardial access was obtained in all Group 2 patients, whereas epicardial ablation was performed in 33% (14) of these patients. RESULTS: Mean ejection fraction was 27 ± 5. During a mean follow-up of 25 ± 10 months, the VAs recurrence rate of any ventricular tachycardia (VTs) was 47% (23 of 49 patients) in Group 1 and 19% (8 of 43 patients) in Group 2 (log-rank p = 0.006). One patient in Group 1 and 1 patient in Group 2 died at follow-up for noncardiac reasons. CONCLUSIONS: Our study demonstrates that ablation using endo-epicardial homogenization of the scar significantly increases freedom from VAs in ischemic cardiomyopathy patients.

Catheter ablation of atrial fibrillation in octogenarians: safety and outcomes.

INTRODUCTION: Radiofrequency catheter ablation (RFCA) is an effective treatment for atrial fibrillation (AF), although studies evaluating the role of RFCA have largely excluded elderly patients. We report the safety and outcomes of RFCA of AF in octogenarians. METHODS AND RESULTS: From 2008 to 2011, out of 2,754 consecutive patients undergoing RFCA of AF, 103 (3.7%) had ≥80 years (age 85 ± 3 years, 4 with >90 years). Pulmonary vein (PV) antrum isolation was performed in paroxysmal AF. In nonparoxysmal AF, ablation was extended to the entire left atrial posterior wall and to complex fractionated electrograms. Non-PV triggers were disclosed by isoproterenol challenge at the end of the procedure and targeted for ablation. Octogenarians presented a high rate of non-PV triggers (84% vs 69%, P = 0.001), especially in patients with paroxysmal AF (62% vs 19%, P < 0.001); non-PV triggers were most commonly mapped in the coronary sinus (54%), left atrial appendage (32%), interatrial septum and superior vena cava (14%). After a mean follow-up of 18 ± 6 months, 71 (69%) octogenarians remained free from AF recurrence off antiarrhythmic drugs after a single procedure (vs 71% in patients <80 years, P = 0.65). The success rate reached 87% after 2 procedures. Total periprocedural complication rates also did not differ between the 2 age groups. CONCLUSIONS: RFCA of AF is safe and effective in octogenarians. A high rate of non-PV triggers is present in these patients, and targeting multiple structures other than the pulmonary veins is often necessary to achieve long-term success.

Identifying the relationship between the non-PV triggers and the critical CFAE sites post-PVAI to curtail the extent of atrial ablation in longstanding persistent AF.

BACKGROUND: Complex fractionated atrial electrograms (CFAE) ablation has been performed in addition to pulmonary veins (PV) isolation to increase the success rate of atrial fibrillation (AF) ablation in patients with longstanding (LS) persistent AF. The mechanism underlying the clinical benefit of CFAE ablation remains, however, poorly understood. OBJECTIVE: We compared the impact of CFAE ablation on the prevalence of non-PV atrial triggers inducing AF in 2 groups of patients with LS persistent AF. One group underwent PVAI alone, and the other group underwent PVAI plus CFAE ablation. In addition, we correlated the site of non-PV triggers with the presence of CFAE. METHODS: A total of 98 consecutive patients with symptomatic drug refractory LS persistent AF presenting for ablation had a preablation electroanatomic CFAE map. Patients randomized to either isolation of the PVs and posterior wall (PVAI) (group I, n = 48 pts) or PVAI and biatrial ablation of CFAEs (group II, 50 pts). After ablation, infusion of isoproterenol up to 30 mcg/min was given to reveal non PV foci inducing AF. Those foci were mapped and correlated with CFAE regions and ablated. RESULTS: A total of 19 patients (76%) with PV foci inducing AF were associated with either stable or transient CFAE after PVAI, respectively, in 12 patients (48%) and 7 patients (28%). A total of 20 (42%) non-PV triggers were observed in group I versus 5 (10%) in group II (P < 0.001) in 18 and 5 patients, respectively. After a mean f/u of 17.2 ± 5.2 months, 33 (69%) patients in group I and 36 (72%) patients in group II were in SR (P = NS). CONCLUSION: Non-PV triggers inducing AF post-PVAI were associated with the presence of stable or transient CFAE in 48% and 28% of cases, respectively, in LS persistent AF. CFAE ablation after PVAI was associated with a significantly higher elimination of those non-PV triggers. This suggests that at least part of the beneficial effect achieved by CFAE ablation reflects elimination of non-PV AF triggers.

Ablation of ventricular arrhythmias in arrhythmogenic right ventricular dysplasia/cardiomyopathy: arrhythmia-free survival after endo-epicardial substrate based mapping and ablation.

BACKGROUND: In patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy, freedom from ventricular arrhythmias (VAs) after endocardial ablation is limited. We compared the long-term freedom from recurrent VAs by using endocardial-alone ablation versus endo-epicardial substrate-based ablation. METHODS AND RESULTS: Forty-nine patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy undergoing ablation of ventricular tachycardia (VT) were divided into 2 groups: endocardial-alone ablation (group 1, n = 23) and endo-epicardial ablation (group 2, n = 26). All patients had an implantable cardioverter-defibrillator (ICD). Conventional and 3D mappings were used to determine the mechanism of induced VTs and to identify area of "scar" or "abnormal" myocardium. All critical sites responsible for VTs and points with "abnormal" potential were targeted for ablation from endocardium (group 1) or from both endocardium and epicardium (group 2). The procedural end point was noninducibility of sustained, monomorphic VT with isoproterenol. The presence of frequent premature ventricular contractions at the end of ablation was recorded. Patients were followed up by ECG, Holter, and ICD interrogation. After a follow-up of at least 3 years, freedom from VAs or ICD therapy was 52.2% (12/23) in group 1 and 84.6% (22/26) in group 2 (P = 0.029), with 21.7% (5/23) and 69.2% (18/26) patients off antiarrhythmic drugs (P < 0.001), respectively. Compared with patients with no premature ventricular contractions after ablation, patients with frequent premature ventricular contractions after ablation were more likely to have VA recurrence/ICD therapy [3/33 (9%) versus 12/16 (75%); log-rank P<0.001]. CONCLUSIONS: An endo-epicardial-based ablation strategy achieves higher long-term freedom from recurrent VAs off antiarrhythmic therapy in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy when compared with endocardial-alone ablation. The presence of ≥ 10 premature ventricular contractions per minute after ablation is associated with more VA recurrence.

Endo-epicardial ablation of ventricular arrhythmias in the left ventricle with the Remote Magnetic Navigation System and the 3.5-mm open irrigated magnetic catheter: results from a large single-center case-control series.

BACKGROUND: Remote magnetic navigation (RMN) has been reported as a feasible and safe mapping and ablation system for treatment of ventricular arrhythmias (VAs). However, the reported success rates have been limited with the 4- and 8-mm catheter tips. OBJECTIVE: This study sought to report the results in a large series of consecutive patients undergoing radiofrequency (RF) catheter ablation of VAs using the RMN with the 3.5-mm magnetic open-irrigated-tip catheter (OIC). METHODS: A total of 110 consecutive patients with a clinical history of left VA were included in the study. In all cases, an OIC was utilized for mapping and ablation. When ablation with the RMN catheters failed, a manual OIC was used to eliminate the VA. Postablation pacing maneuvers and isoproterenol were used to verify the inducibility of the VAs. Outcomes were compared with those of a group of 92 consecutive patients undergoing manual ablation by the same operator. RESULTS: Mapping and ablation with the magnetic OIC were performed in all 110 patients with VA. Ischemic cardiomyopathy was present in 33 (30%), nonischemic in 14 (13%), and in 63 (57%) patients no structural heart disease was present. Endocardial mapping was performed in all patients, whereas both endocardial and epicardial mapping were performed in 36 (33%) patients. Compared with manual ablation, RMN was associated with a longer procedural time (2.9 +/- 1.2 hours vs. 3.3 +/- 1.1 hours, P = 0.004) and RF time (24 +/- 12 minutes vs. 33 +/- 18 minutes, P = 0.005), whereas fluoroscopic time was significantly shorter (35 +/- 22 minutes vs. 26 +/- 14 minutes, P = 0.033). During the procedures, crossover to manual ablation was required in 15 patients (14%). At 11.7 +/- 2.1 months of follow-up in the study group and 18.7 +/- 3.7 months in the manual ablation group, 85% and 86% (P = 0.817) of patients, respectively, were free of VA. CONCLUSION: This large series of consecutive patients demonstrates that OIC ablation using RMN is effective for the treatment of left VAs.