Catheter Ablation of Scar-mediated Ventricular Tachycardia: Are Substrate-based Approaches Replacing Mapping?

Scar-mediated ventricular tachycardia (VT) is a recognized cause of morbidity and mortality in patients with ischemic cardiomyopathy and other cardiomyopathies such as nonischemic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, and cardiac sarcoidosis. Implantable cardioverter-defibrillator (ICD) therapy improves survival but does not prevent the onset of recurrent VT or associated morbidity from ICD shocks. While randomized controlled trials have demonstrated advantages of scar-mediated VT ablation in comparison with antiarrhythmic drugs, procedural success has remained overall modest at between 50% and 70%. Standard scar-mediated VT ablation has relied on the use of activation and entrainment mapping during sustained VT to identify critical isthmuses for ablation. Substrate-based approaches have emerged as options to address hemodynamically unstable VT and have focused on identifying electrograms characteristic of critical isthmuses (eg, late potentials, local abnormal ventricular activities, conducting channels) within dense scar during sinus rhythm. Scar homogenization, a more recent approach, relies minimally on mapping and focuses on complete substrate modification. Core isolation, on the other hand, another recent development, relies heavily on mapping to identify regions within scar that are "cores" for arrhythmogenicity and then concentrates ablation to these areas. At this time, scar-mediated VT ablation appears to be at a crossroads wherein evolving substrate-based approaches are exploring whether to rely less or increasingly more on mapping. This review will therefore discuss the evolution of substrate-based, scar-mediated VT ablation and in the process try to answer whether there is still a role for mapping.

Impact of weight loss on ablation outcome in obese patients with longstanding persistent atrial fibrillation.

AIMS: This study investigated the impact of weight loss in longstanding persistent (LSPAF) patients undergoing catheter ablation (CA). METHODS: Ninety consecutive obese LSPAF patients were approached; 58 volunteered to try weight loss interventions for up to 1 year (group 1), while 32 patients declined weight loss interventions and were included as a control (group 2). Both groups remained on antiarrhythmic drugs. If they continued to experience AF, CA was performed. Body weight was measured at 6-month intervals and arrhythmia status was assessed by event recorder, electrocardiogram (ECG), and Holter monitoring. Symptom severity and quality of life (QoL) were evaluated by AFSS and SF-36 survey, respectively. A scoring algorithm with two summary measures, physical component score (PCS) and mental component score (MCS), was prepared for QoL analysis. RESULTS: Significant reduction in body weight (median -24.9 (IQR -19.1 to -56.7) kg, P < 0.001) was observed in the group 1 patients, while no such change was seen in group 2. The PCS and MCS scores improved significantly in group 1 only, with a change from baseline of 8.4 ± 3 (P = 0.013) and 12.8 ± 8.2 (P < 0.02). However, AF symptom severity remained unchanged from baseline in both groups (P = 0.84). All 90 patients eventually underwent CA and received PVAI+ posterior wall+ non-PV triggers ablation. At 1-year follow-up after single procedure, 37 (63.8%) in group 1 and 19 (59.3%) patients in group 2 remained arrhythmia-free off AAD (P = 0.68). CONCLUSION: In this prospective analysis, in LSPAF patients weight loss improved QoL but had no impact on symptom severity and long-term ablation outcome.

Procedural findings and ablation outcome in patients with atrial fibrillation referred after two or more failed catheter ablations.

INTRODUCTION: This study reports the procedural findings and ablation outcome in AF patients referred after ≥2 failed PV isolation (PVI). METHODS: Three hundred and five consecutive AF patients referred after ≥2 PVI were included in the analysis. High-dose isoproterenol challenge was used to identify PV reconnection and non-PV triggers; the latter were ablated based on the operator's discretion during the index procedure. At the repeat procedure, non-PV triggers were ablated in all. Empirical isolation of LA appendage (LAA) and coronary sinus (CS) was performed if the PVs were silent and no non-PV triggers were detected. RESULTS: PV reconnection was detected in 226 and non-PV triggers were identified or empirically isolated in 285 patients during the index procedure. At follow-up, 182 (60%) patients were recurrence-free off-AAD; the success rate with and without non-PV ablation was 81% vs. 8% (P < 0.0001). 104 patients underwent repeat procedure with non-PV trigger ablation in all. At 1 year, 90% were arrhythmia free off-AAD in non-PV ablation group, and 72% who did not receive non-PV triggers ablation at the index procedure (P = 0.035). The success rate of empirical LAA and CS isolation was 78.5% and 82% after the index and repeat procedure, respectively. CONCLUSION: In patients experiencing AF recurrence after multiple failed PVI, despite PV reconnection, non-PV triggers were found to be responsible for AF maintenance in the majority and ablating those triggers increased ablation success. Additionally, in the presence of permanent PVI and no non-PV triggers on isoproterenol, empirical isolation of LAA and CS provided high rate of arrhythmia-free survival.

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).

Scar Homogenization Versus Limited-Substrate Ablation in Patients With Nonischemic Cardiomyopathy and Ventricular Tachycardia.

BACKGROUND: Scar homogenization improves long-term ventricular arrhythmia-free survival compared with standard limited-substrate ablation in patients with post-infarction ventricular tachycardia (VT). Whether such benefit extends to patients with nonischemic cardiomyopathy and scar-related VT is unclear. OBJECTIVES: The aim of this study was to assess the long-term efficacy of an endoepicardial scar homogenization approach compared with standard ablation in this population. METHODS: Consecutive patients with dilated nonischemic cardiomyopathy (n = 93), scar-related VTs, and evidence of low-voltage regions on the basis of pre-defined criteria on electroanatomic mapping (i.e., bipolar voltage <1.5 mV) underwent either standard VT ablation (group 1 [n = 57]) or endoepicardial ablation of all abnormal potentials within the electroanatomic scar (group 2 [n = 36]). Acute procedural success was defined as noninducibility of any VT at the end of the procedure; long-term success was defined as freedom from any ventricular arrhythmia at follow-up. RESULTS: Acute procedural success rates were 69.4% and 42.1% after scar homogenization and standard ablation, respectively (p = 0.01). During a mean follow-up period of 14 ± 2 months, single-procedure success rates were 63.9% after scar homogenization and 38.6% after standard ablation (p = 0.031). After multivariate analysis, scar homogenization and left ventricular ejection fraction were predictors of long-term success. During follow-up, the rehospitalization rate was significantly lower in the scar homogenization group (p = 0.035). CONCLUSIONS: In patients with dilated nonischemic cardiomyopathy, scar-related VT, and evidence of low-voltage regions on electroanatomic mapping, endoepicardial homogenization of the scar significantly increased freedom from any recurrent ventricular arrhythmia compared with a standard limited-substrate ablation. However, the success rate with this approach appeared to be lower than previously reported with ischemic cardiomyopathy, presumably because of the septal and midmyocardial distribution of the scar in some patients.

Pulmonary Vein Antrum Isolation in Patients With Paroxysmal Atrial Fibrillation: More Than a Decade of Follow-Up.

BACKGROUND: We report the outcome of pulmonary vein (PV) antrum isolation in paroxysmal atrial fibrillation (AF) patients over more than a decade of follow-up. METHODS AND RESULTS: A total of 513 paroxysmal AF patients (age 54±11 years, 73% males) undergoing catheter ablation at our institutions were included in this analysis. PV antrum isolation extended to the posterior wall between PVs plus empirical isolation of the superior vena cava was performed in all. Non-PV triggers were targeted during repeat procedure(s). Follow-up was performed quarterly for the first year and every 6 to 9 months thereafter. The outcome of this study was freedom from recurrent AF/atrial tachycardia. At 12 years, single-procedure arrhythmia-free survival was achieved in 58.7% of patients. Overall, the rate of recurrent arrhythmia (AF/atrial tachycardia) was 21% at 1 year, 11% between 1 and 3 years, 4% between 3 and 6 years, and 5.3% between 6 and 12 years. Repeat procedure was performed in 74% of patients. Reconnection in the PV antrum was found in 31% of patients after a single procedure and in no patients after 2 procedures. Non-PV triggers were found and targeted in all patients presenting with recurrent arrhythmia after ≥2 procedures. At 12 years, after multiple procedures, freedom from recurrent AF/atrial tachycardia was achieved in 87%. CONCLUSIONS: In patients with paroxysmal AF undergoing extended PV antrum isolation, the rate of late recurrence is lower than what previously reported with segmental or less extensive antral isolation. However, over more than a decade of follow-up, nearly 14% of patients developed recurrence because of new non-PV triggers.

Ablation Versus Amiodarone for Treatment of Persistent Atrial Fibrillation in Patients With Congestive Heart Failure and an Implanted Device: Results From the AATAC Multicenter Randomized Trial.

BACKGROUND: Whether catheter ablation (CA) is superior to amiodarone (AMIO) for the treatment of persistent atrial fibrillation (AF) in patients with heart failure is unknown. METHODS AND RESULTS: This was an open-label, randomized, parallel-group, multicenter study. Patients with persistent AF, dual-chamber implantable cardioverter defibrillator or cardiac resynchronization therapy defibrillator, New York Heart Association II to III, and left ventricular ejection fraction <40% within the past 6 months were randomly assigned (1:1 ratio) to undergo CA for AF (group 1, n=102) or receive AMIO (group 2, n=101). Recurrence of AF was the primary end point. All-cause mortality and unplanned hospitalization were the secondary end points. Patients were followed up for a minimum of 24 months. At the end of follow-up, 71 (70%; 95% confidence interval, 60%-78%) patients in group 1 were recurrence free after an average of 1.4±0.6 procedures in comparison with 34 (34%; 95% confidence interval, 25%-44%) in group 2 (log-rank P<0.001). The success rate of CA in the different centers after a single procedure ranged from 29% to 61%. After adjusting for covariates in the multivariable model, AMIO therapy was found to be significantly more likely to fail (hazard ratio, 2.5; 95% confidence interval, 1.5-4.3; P<0.001) than CA. Over the 2-year follow-up, the unplanned hospitalization rate was (32 [31%] in group 1 and 58 [57%] in group 2; P<0.001), showing 45% relative risk reduction (relative risk, 0.55; 95% confidence interval, 0.39-0.76). A significantly lower mortality was observed in CA (8 [8%] versus AMIO (18 [18%]; P=0.037). CONCLUSIONS: This multicenter randomized study shows that CA of AF is superior to AMIO in achieving freedom from AF at long-term follow-up and reducing unplanned hospitalization and mortality in patients with heart failure and persistent AF. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00729911.

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.

Pulmonary Vein Isolation to Reduce Future Risk of Atrial Fibrillation in Patients Undergoing Typical Flutter Ablation: Results from a Randomized Pilot Study (REDUCE AF).

BACKGROUND: This study examined incidence of AF following cavotricuspid isthmus (CTI) ablation alone or CTI plus prophylactic pulmonary vein isolation (PVI) in patients presenting with isolated atrial flutter (AFL) with no history of AF. METHODS AND RESULTS: We enrolled 216 patients with isolated typical atrial flutter and randomized them to CTI alone (group 1, n = 108, 61.2 ± 9.7 year, 75% male) or CTI+PVI ablation (group 2, n = 108, 62.4 ± 9.3 year, 73% male). Insertible loop recorder (ILR) was implanted in 21 and 19 patients from groups 1 and 2, respectively. Remaining patients were monitored with event recorders, ECG, 7-day Holter. Follow-up period was for 18 ± 6 months. Compared to group 1, group 2 had significantly longer procedural duration (75.9 ± 33 min vs. 161 ± 48 min [P < 0.001]) and fluoroscopy time (15.9 ± 12.3 min vs. 56.4+21 min [P < 0.001]). At the end of follow-up, 65 (60.2%) in group 1 and 77 (71.3%) in group 2 were arrhythmia free off-AAD (log-rank P = 0.044). A subgroup analysis was performed with 55 year age cut-off. In the <55 age group the CTI only population had similar success as in CTI+PVI, (21 of 24 [83.3%] vs. 19 of 22 [86.4%], respectively, log-rank P = 0.74). In the ≥55 group, having CTI+PVI showed significantly higher success compared to CTI only; 45 of 84 (53.6%) were AF/AT free in CTI only group versus 58 of 86 (67.4%) with CTI+PVI (log-rank P = 0.029). CONCLUSION: Prophylactic PVI reduced new-onset AF in patients with lone atrial flutter.

Feasibility and safety of uninterrupted periprocedural apixaban administration in patients undergoing radiofrequency catheter ablation for atrial fibrillation: Results from a multicenter study.

BACKGROUND: Periprocedural anticoagulation management with uninterrupted warfarin and a "therapeutic" international normalized ratio is the best approach for reducing both thromboembolic and bleeding complications in the setting of catheter ablation for atrial fibrillation (AF). OBJECTIVE: The purpose of this study was to evaluate the safety and feasibility of uninterrupted apixaban in this setting. METHODS: This was a prospective multicenter registry of AF patients undergoing radiofrequency catheter ablation at 4 institutions in United States and Europe with uninterrupted apixaban. These patients were compared with an equal number of patients, matched for age, gender, and type of AF, undergoing AF ablation on uninterrupted warfarin. The apixaban group was comprised of consecutive patients who had taken their last dose of apixaban the morning of the procedure. A subset of 29 patients in the apixaban group underwent diffusion magnetic resonance imaging (dMRI) to detect silent cerebral ischemia. RESULTS: A total of 400 patients (200 patients in each group) were included in the study. The average age was 65.9 ± 9.9 years, 286 (71.5%) were male, and 334 (83.5%) had nonparoxysmal AF. There were no statistical differences with regard to major complications (1% vs 0.5%, P = 1), minor complications (3.5% vs 2.5%, P = .56), or total bleeding complications (4.5% vs 3%, P = .43) between the apixaban and warfarin groups. There were no symptomatic thromboembolic complications. All dMRIs were negative for "new" silent cerebral ischemia in the apixaban group. CONCLUSION: Uninterrupted apixaban administration in patients undergoing AF ablation seems to be feasible and effective in preventing clinical and silent thromboembolic events without increasing the risk of major bleeding.

Impact of Uncontrolled Hypertension on Atrial Fibrillation Ablation Outcome.

OBJECTIVES: The goal of this study was to evaluate the impact of hypertension on the outcome of atrial fibrillation (AF) ablation. BACKGROUND: Hypertension is a well-known independent risk factor for incident AF. METHODS: A total of 531 consecutive patients undergoing AF ablation were enrolled in this study and divided into 3 groups: patients with uncontrolled hypertension despite medical treatment (group I, n = 160), patients with controlled hypertension (group II, n = 192), and patients without hypertension (group III, n = 179). Pulmonary vein (PV) antrum and posterior wall isolation was always performed, and non-PV triggers were identified during isoproterenol infusion. All patients underwent extensive follow-up. RESULTS: Three groups differed in terms of left atrial (LA) size, non-PV triggers, and moderate/severe LA scar. Non-PV triggers were present in 94 (58.8%), 64 (33.3%), and 50 (27.9%) patients in groups I, II, and III, respectively (p < 0.001). After 19 ± 7.7 months of follow-up, 65 (40.6%), 54 (28.1%), and 46 (25.7%) patients in groups I, II, and III had recurrences (log-rank test, p = 0.003). Among patients in group I who underwent additional non-PV trigger ablation, freedom from AF/atrial tachycardia was 69.8%, which was similar to groups II and III procedural success (log-rank p = 0.7). After adjusting for confounders, uncontrolled hypertension (group I) (hazard ratio [HR]: 1.52, p = 0.045), non-PV triggers (HR: 1.85, p < 0.001), and nonparoxysmal AF (HR: 1.64, p = 0.002) demonstrated significant association with arrhythmia recurrence. CONCLUSIONS: Controlled hypertension does not affect the AF ablation outcome when compared with patients without hypertension. By contrast, uncontrolled hypertension confers higher AF recurrence risk and requires more extensive ablation.

Ablation of Stable VTs Versus Substrate Ablation in Ischemic Cardiomyopathy: The VISTA Randomized Multicenter Trial.

BACKGROUND: Catheter ablation reduces ventricular tachycardia (VT) recurrence and implantable cardioverter defibrillator shocks in patients with VT and ischemic cardiomyopathy. The most effective catheter ablation technique is unknown. OBJECTIVES: This study determined rates of VT recurrence in patients undergoing ablation limited to clinical VT along with mappable VTs ("clinical ablation") versus substrate-based ablation. METHODS: Subjects with ischemic cardiomyopathy and hemodynamically tolerated VT were randomized to clinical ablation (n = 60) versus substrate-based ablation that targeted all "abnormal" electrograms in the scar (n = 58). Primary endpoint was recurrence of VT. Secondary endpoints included periprocedural complications, 12-month mortality, and rehospitalizations. RESULTS: At 12-month follow-up, 9 (15.5%) and 29 (48.3%) patients had VT recurrence in substrate-based and clinical VT ablation groups, respectively (log-rank p < 0.001). More patients undergoing clinical VT ablation (58%) were on antiarrhythmic drugs after ablation versus substrate-based ablation (12%; p < 0.001). Seven (12%) patients with substrate ablation and 19 (32%) with clinical ablation required rehospitalization (p = 0.014). Overall 12-month mortality was 11.9%; 8.6% in substrate ablation and 15.0% in clinical ablation groups, respectively (log-rank p = 0.21). Combined incidence of rehospitalization and mortality was significantly lower with substrate ablation (p = 0.003). Periprocedural complications were similar in both groups (p = 0.61). CONCLUSIONS: An extensive substrate-based ablation approach is superior to ablation targeting only clinical and stable VTs in patients with ischemic cardiomyopathy presenting with tolerated VT. (Ablation of Clinical Ventricular Tachycardia Versus Addition of Substrate Ablation on the Long Term Success Rate of VT Ablation (VISTA); NCT01045668).

Effect of periprocedural amiodarone on procedure outcome in patients with longstanding persistent atrial fibrillation undergoing extended pulmonary vein antrum isolation: results from a randomized study (SPECULATE).

BACKGROUND: The impact of amiodarone on ablation outcome in longstanding persistent atrial fibrillation (LSPAF) patients is not known yet. OBJECTIVE: The purpose of this study was to assess the effect of amiodarone on procedural-outcomes in LSPAF patients undergoing catheter ablation. METHODS: We enrolled 112 LSPAF patients on amiodarone and scheduled to undergo atrial fibrillation (AF) ablation. Patients were randomized to amiodarone discontinuation 4 months before ablation (group 1, n = 56) and a control group (group 2, n = 56) in which ablation was performed without amiodarone discontinuation. All patients underwent pulmonary vein (PV) antrum and posterior wall isolation, defragmentation and extra PV triggers ablation. Patients were followed up for recurrence for 32 ± 8 months post-ablation. Repeat procedures in all recurrent patients were performed off amiodarone. RESULTS: During ablation, AF termination was more frequent in group 2 compared to group 1 [44 (79%) vs 32 (57%), P = .015]. After high-dosage isoproterenol, more non-PV triggers were disclosed in group 1 compared to group 2 (42 [75%] vs 24 [43%] respectively, P <.001). Group 2 had lower procedure, radiofrequency and fluoroscopy times compared to group 1 (2.7 ± 1 vs 3.1 ± 1 h, 69 ± 13 min vs 87 ± 11 min and 64 ± 14 min vs 85 ± 18 min respectively, p < .05). At 32 ± 8 month follow-up, on or off antiarrhythmic drug success rate was 37 (66%) in group 1 and 27 (48%) in group 2 (P = .04). During redo, new non-PV trigger sites were identified in group 2 patients. CONCLUSION: Periprocedural continuous amiodarone was associated with higher organization rate and lower radiofrequency ablation rate. However, masking non-PV triggers increased the late recurrence rate.