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The percutaneous epicardial approach has become an adjunctive tool for electrophysiologists to treat disparate cardiac arrhythmias, including accessory pathways, atrial tachycardia, and particularly ventricular tachycardia. This novel technique prompted a strong impulse to perform epicardial access as an alternative strategy for pacing and defibrillation, left atrial appendage exclusion, heart failure with preserved ejection fraction, and genetically engineered tissue delivery. However, because of the incremental risk of major complications compared with stand-alone endocardial ablation, it is still practiced in a limited number of highly experienced centers across the world.

Aims Transesophageal echocardiography (TEE) is a standard peri-procedural imaging modality in patients undergoing percutaneous left atrial appendage (LAA) occlusion. An accurate device sizing is pivotal to assess stability and achieve successful closure. In this prospective study, we sought to evaluate the correlation between Watchman device compression rates (DCRs) and risk of incomplete LAA occlusion at follow-up in patients undergoing Watchman device implantation. Methods and results Two-dimensional TEE via a commercially available transducer (Vivid, Philips) was performed during the procedure and within 3 months after the procedure. LAA size, morphology, and DCRs [(original device size—size after deployment)/original device size; %] were assessed in a mid-oesophageal view at 0°, 45°, 90° and 135°, according to company recommendations. Residual leaks ≥ 3 mm were classified as significant. Between 2016 and 2018, 116 patients underwent LAA occlusion with a Watchman device at our institution. The mean age was 74 ± 9 years and 60.4% (n = 70) were males. The average CHA2DS2-VASc and HAS-BLED scores were 4.7 ± 1.7 and 2.5 ± 1.1, respectively. The final device size was 21 mm in 11 (9.5%) patients, 24 mm in 28 (24.1), 27 mm in 27 (23.3%), 30 mm in 26 (22.4%), and 33 mm in 24 (20.7). At follow-up TEE, 16 (13.8%) patients were found to have a significant (≥3 mm) residual leak. The average DCRs measured at different angles in patients with and without leak were not significantly different (24 ± 8% vs. 26 ± 7% at 0°, P = 0.47; 23 ± 9% vs. 25 ± 7% at 45°, P = 0.58; 23 ± 8% vs. 23 ± 6% at 90°, P = 0.61; 22 ± 8% vs. 21 ± 7% at 135°, P = 0.61). At receiver operating characteristic (ROC) analysis, the areas under the curve to discriminate between patients with/without leak were 0.58, 0.57, 0.55, and 0.46 for DCRs measured at 0°, 45°, 90°, and 135° angles. Conclusions Peri-procedural assessment of DCRs does not appear to be an accurate method to predict LAA complete occlusion in patients undergoing Watchman device implantation.

Aims A significant amount of atrial fibrillation patients does not receive appropriate anticoagulation, owing to contraindications and side effects. Octogenarians have higher competing comorbidities with a remarkable bleeding/thromboembolic (TE) risk. We aimed at analysing the clinical outcomes of LAAO compared with direct oral anticoagulation (DOAC) in octogenarians. Methods and results Data were extracted from two prospective databases including 488 LAAO and 825 DOAC patients. Patients aged 80 years or older accounted for 37.1% (n = 181) and 39.5% (n = 326). In order to attenuate the imbalance in covariates between the groups, a propensity score matching technique was used (covariates: age, sex, CHA2DS2-VASc, and HAS-BLED scores, follow-up duration; tolerance 0.02). This method resulted in matched populations with 108 octogenarian patients per group. The annual stroke/transient ischaemic attack (TIA) risk was estimated based on the CHA2DS2-VASc, and compared to the annualized observed risk, owing to calculate the % risk reduction associated with the two treatment strategies. A total of 216 octogenarians were included in the analysis (84 ± 3 years; CHA2DS2-VASc: 4.9 ± 1.4, HAS-BLED: 3.1 ± 0.9). A Watchman device was successfully deployed in all LAAO ≥ 80 patients; periprocedural adverse events were observed in 2.8% (n = 3) of LAAO patients. During a follow-up of 13 ± 4 months, 3 (2.8%) TE complications (1 stroke, 2 TIA) occurred in LAAO ≥ 80 pts and 4 (3.7%; 1 stroke, 3 TIA) in DOAC ≥ 80 pts (P = 0.99). The annualized risk of stroke/TIA was 2.5% in the first and 3.5% in the second group. Based on the estimated annual TE risk according to the CHA2DS2-VASc score, the % risk reduction after LAAO and DOAC was 54.5% and 36.4%, respectively. Major bleeding events were 3 [1 intracranial, 2 gastrointestinal (GI)] LAAO ≥ 80 pts, and 3 (2 intracranial, 1GI) in DOAC ≥ 80 pts (2.8% in both groups). Minor bleeding events were significantly higher in DOAC ≥ 80 pts [13.0% (n = 14) vs. 2.7% (n = 3); RR: 4.7, 95% CI: 1.4–15.7; P = 0.009]. Conclusions LAAO was safe and similar to DOAC at preventing ischaemic/major bleeding events in a matched population of patients aged ≥80 years. A significantly higher incidence of minor bleeding events was observed in the DOAC group.

Aims Left atrial appendage occlusion (LAAO) might be particularly attractive in chronic kidney disease (CKD) patients, owing to a high thromboembolic risk and an even higher risk of bleeding. We sought to evaluate the safety and effectiveness of LAAO in CKD patients. Methods and results A total of 1238 patients undergoing LAAO at six centres were enrolled. On the basis of kidney function, as assessed via the CKD-EPI formula, patients were classified in two groups. Group1 had a GFR value ≤60 ml/min/1.73 m2 (CKD stages 3a-b, 4, and 5), whereas Group2 had a function >60 ml/min/1.73 m2 (CKD stages 1 and 2). Predicted annual rates of TE or major bleeding events were compared to the annualized observed risk of the two populations. Compared to Group 2 (n = 720, 47.5% males), patients in Group 1 (n = 518, 86.5% males) were older (mean age: 78 ± 8 vs. 75 ± 8, P Conclusions LAAO is a safe and effective approach in CKD patients. Given the increased risk of bleeding and contraindications to oral anticoagulation, CKD patients might be good candidates for LAA occlusion.

Aims Despite advances in success rate of paroxysmal atrial fibrillation (PAF) ablation, outcomes of radiofrequency catheter ablation (RFCA) in patients with persistent AF are highly variable. Early persistent AF (EPsAF) is defined as AF that is sustained beyond 7 days but is less than 3 months in duration. Arrhythmia-free survival data after RFCA in this specific population are still limited. We sought to report the outcomes of RFCA in the subgroup of patients with EPsAF, compared to those with PAF and with ‘late’ persistent AF (LPsAF) lasting between 3 and 12 months. Methods and results Data from 1143 consecutive AF patients receiving their first RFCA were prospectively collected. Patients with EPsAF (n = 190) were compared with PAF (n = 531) and LPsAF (n = 422) patients. All patients received pulmonary vein antrum isolation + posterior wall and sustained non-pulmonary vein (PV) trigger ablation. Non-sustained non-PV triggers were ablated based on operator discretion. Non-PV triggers were defined as sites of firing leading to sustained (>30 s) or non-sustained arrhythmias ( Conclusions In patients with EPsAF, RFCA may result in significantly better freedom from atrial arrhythmias, compared to LPsAF. In this cohort, ablation might be reasonable as first line approach to improve outcomes and prevent AF progression.

Aims Left atrial appendage occlusion (LAAO) with the Watchman device is an effective alternative to oral anticoagulation in patients with non-valvular atrial fibrillation at high thromboembolic risk. We sought to evaluate the safety and effectiveness of LAAO for stroke and bleeding prevention in patients at very high stroke risk. Methods and results Data were extracted from a prospective database of 488 AF patients who underwent LAA closure with a Watchman device. Periprocedural complications, thromboembolic (TE), and bleeding event rates among patients with a CHA2DS2-VASc ≥ 5 were reported. Predicted annual rates of TE or major bleeding events were compared to the annualized observed risk of the population. Overall, 209 patients with a CHA2DS2-VASc ≥5 (CHA2DS2-VASc: 6.0 ± 1.0; HAS-BLED: 3.7 ± 1.1) were included in the study. The mean age was 78 ± 6 years and 52.2% (n = 109) were males. Watchman implantation was successful in all patients. Overall procedure-related complication rate was 3.3% (n = 7). Two major complications were observed (1.0%): one pericardial tamponade requiring surgery and one major bleeding event at 3 days post-procedure. The incidence of minor complications was 2.3% (n = 5). Specifically, two patients experienced a pericardial effusion that required drainage and three had a groin hematoma. During a mean follow-up duration of 12 ± 5 months (193 pt/years), six TE events (2.9%/annualized rate: 3.1%) were documented after a median of 6.3 months (IQR: 2.2–9.6). Based on the estimated annual TE risk according to the CHA2DS2-VASc score (8.5%), the % risk reduction after LAAO was 63.5%. Four major bleeding events [1.9% (median time to event: 2.1 months; IQR: 1.0–3.4)] and five minor bleeding events occurred (2.5%) during follow-up. Compared to the expected rate of bleeding events as assessed by the HAS-BLED of the population (8.03%), LAAO led to a 42% reduction of bleeding risk. Conclusions In a population at very high TE risk, LAAO with the Watchman device was a safe and effective approach, and led to a 63.5% of stroke risk.

BACKGROUND Atrioesophageal fistula (AEF) is a worrisome complication of atrial fibrillation (AF) ablation. Its clinical manifestations and time course are unpredictable and may contribute to diagnostic and treatment delays. We conducted a systematic review of all available cases of AEF, aiming at characterizing clinical presentation, time course, diagnostic pitfalls, and outcomes. METHODS The digital search retrieved 150 studies containing 257 cases, 238 (92.6%) of which with a confirmed diagnosis of AEF and 19 (7.4%) of pericardioesophageal fistula. RESULTS The median time from ablation to symptom onset was 21 days (interquartile range [IQR]: 11-28). Neurological abnormalities were documented in 75% of patients. Compared to patients seen by a specialist, those evaluated at a walk-in clinic or community hospital had a significantly greater delay between symptom onset and hospital admission (median: 2.5 day [IQR: 1-8] vs. 1 day [IQR: 1-5); p = .03). Overall, 198 patients underwent a chest scan (computed tomography [CT]: 192 patients and magnetic resonance imaging [MRI]: 6 patients), 48 (24.2%; 46 CT and 2 MRI) of whom had normal/unremarkable findings. Time from hospital admission to diagnostic confirmation was significantly longer in patients with a first normal/unremarkable chest scan (p

BACKGROUND This study evaluated the arrhythmia profile and ablation outcome in women with atrial fibrillation (AF) aged ≥75 years. METHODS A total of 573 consecutive female patients undergoing first AF ablation were classified into group 1: ≥75 years (n = 221) and group 2

Background: A considerable proportion of elderly patients are known to have coexistent atrial fibrillation (AF) and amyloidosis. Both conditions increase stroke risk. Objective: We evaluated the best anticoagulation strategy in a series of AF patients with amyloidosis. Methods: Consecutive AF patients with coexistent amyloidosis undergoing catheter ablation at our center were included in the analysis. Based on the stroke-prophylaxis approach they were divided into 2 groups; group 1: left atrial appendage occlusion (LAAO) with Watchman and group 2: oral anticoagulation. Following LAAO, all patients remained on full dose non-vitamin K oral anticoagulants (NOAC) for 45 days. Transesophageal echocardiogram (TEE) was performed at 45 days to assess completeness of closure. If the occlusion was complete, patients were kept on aspirin, 81 mg/day for long-term. In case of leak or dense ‘smoke’ in the left atrium (LA) or enlarged LA, they were prescribed half-dose NOAC. NOACs included dabigatran, apixaban, endoxaban and rivaroxaban. Group 2 patients remained on full-dose NOAC during the whole study period (1 year). All patients were prospectively followed up for 1 year. Results: A total of 87 patients were included in the analysis; group 1: 56 and group 2: 31 . CHA 2 DS 2 -VASc score was comparable between the groups (gr. 1: 3.7±1.6 and gr. 2: 3.2±1.7, p=0.18). The most commonly used NOACs were apixaban (45, 51.7%) and rivaroxaban (34, 39%). After the 45-day TEE, 34 patients from group 1 remained on baby-aspirin and 22 on half-dose NOAC. Of the 22, 12 patients had leaks Conclusion: In our series of patients with coexistent AF and amyloidosis, half-dose NOAC following LAA occlusion procedure was observed to be the safest stroke-prophylaxis strategy.

Background: Transthyretin (TTR), a transport protein produced by liver, is closely associated with amyloidosis. Tetramers of TTR circulating in blood can dissociate to monomers that misassemble into amyloid fibrils. Although amyloidosis is a frequent finding in aged atrial fibrillation (AF) patients, the relevance of serum-TTR in AF is unknown. Objective: We evaluated if post-ablation change in serum-TTR level has any prognostic association with long-term ablation outcome in AF patients. Methods: One-hundred-forty-five patients (age: 62.8 ± 6.2years, male 69%, non-paroxysmal AF 41%, BMI : 30.8 ± 6.3) were included in this prospective study. Patients with chronic inflammatory conditions or taking anti-inflammatory drugs were excluded. All patients received pulmonary vein isolation plus isolation of left atrial posterior wall and superior vena cava. In non-paroxysmal AF, non-PV triggers identified by isoproterenol challenge were ablated. Fasting blood samples were collected at baseline and 24-hours post-ablation. Samples were tested for TTR using an automated quantitative test. Results: Mean TTR concentration was 27.94±6.5 mg/dL at baseline and 26.33±9.2 mg/dL at 24-hour post ablation (p Conclusion: Our findings demonstrated significant association of higher recurrence rate with decreased serum-TTR tetramer level at 24-hour post-ablation.

Background: Autoimmune disorders (AuID) are pro-inflammatory conditions and inflammation is known to promote atrial fibrillation (AF). We evaluated the arrhythmia profile in female AF patients with vs without AuID. Methods: Consecutive female patients undergoing their first catheter ablation at our center were included in the analysis and divided into two groups; group 1: with AuID (n=192) and group 2: no AuID (n=2324). All received PV isolation + isolation of left atrial posterior wall and superior vena cava. Additionally, non-PV triggers identified by isoproterenol-challenge were ablated in all.Patients were included in group 1 if they had an established diagnosis of Type 1 Diabetes (DM), rheumatoid arthritis (RA), Lupus, inflammatory bowel disease (IBD), Psoriasis, Sjogren syndrome, Grave’s disease or Celiac disease. Results: Baseline characteristics of the study groups are provided in table 1. Most prevalent AuID were DM (56, 29%), RA (52, 27%), Lupus (35, 18.2%) and IBD (40, 20.8%). Patients with AuID were significantly younger and more had non-paroxysmal AF. They also had larger LA diameter and lower LVEF compared to the group with no AuID. Significantly higher number of non-PV triggers were detected in group 1 patients (149 (77.6%) vs 883 (38%), p Conclusion: Women with autoimmune diseases experienced AF at an earlier age with significantly more non-paroxysmal AF compared to those without. However, similar ablation success was observed in both groups that could be attributed to the ablation strategy including all detectable non-PV triggers. Table

Background Atrial fibrillation (AF) is a disease of the elderly and women typically present with AF at an older age than men do. Moreover, they tend to experience more symptoms and post-ablation recurrences, have worse quality of life and increased risk of stroke and mortality. Objective We evaluated long-term efficacy of our standard ablation approach of extended pulmonary vein isolation (PVI) in octogenarian women undergoing their first AF ablation. Methods Consecutive female AF patients aged ≥80 years receiving their first catheter ablation at our center were included in the analysis. Our standard ablation approach at the first procedure includes PVI + empirical isolation of left atrial posterior wall (LAPW) and superior vena cava (SVC). Complete abolition of all potentials rather than decrease in amplitudes was the procedural end point. Patients were prospectively monitored at regular intervals for 3 years after the index procedure with event recorders, 12-lead ECG, cardiology evaluation at office visits and 7-day Holter monitoring. Results A total of 194 patients with mean age of 84.2±1.4 years were included in the analysis. Of the 194, 120 (61.8%) had non-paroxysmal AF. All received PVI+ isolation of LAPW and SVC. Acute procedural success was achieved in 100% of cases. At 3 years of follow-up, 24 (12.4%) patients remained in sinus rhythm; 22 on- and 2 off-antiarrhythmic drugs (AAD). All of the 23 patients had paroxysmal AF as their initial diagnosis. Of the 170 patients experiencing recurrence, 147 underwent repeat ablation. PV/PW/SVC reconnection was noted in only 6 (4.1%) patients at redo. Triggers originating from non-PV sites were targeted for ablation in all. At 1.5 years after the repeat procedure, 136 (92.5%) patients were in sinus rhythm; 131 off-AAD and 5 patients on-AAD. Conclusion Extended PVI including isolation of posterior wall and SVC was not sufficient to maintain long-term sinus rhythm in majority of octogenarian women, regardless of AF type. Moreover, non-PV triggers rather than PV reconnection was the major cause of recurrence in this subset of AF population. Funding Acknowledgement Type of funding source: None

It is unclear whether isolation of the left atrial posterior wall (LAPW) offers additional benefits over pulmonary vein antrum isolation (PVAI) alone in patients with persistent atrial fibrillation (AF).We sought to determine the impact of PVAI and LAPW isolation (PVAI+LAPW) versus PVAI alone on the outcome of ablation of persistent AF.During the first procedure, PVAI was performed in 20 patients (group 1), whereas in 32 patients (group 2), PVAI was extended to the left atrial (LA) septum and coronary sinus (CS), and isolation of the LAPW was targeted (ePVAI+LAPW). Isolation of the superior vena cava was achieved in both groups. All patients, regardless of arrhythmia recurrence, underwent a second procedure 3 months after the first procedure. In patients with reconnection of pulmonary veins or LAPW, reisolation was performed, and a third procedure was performed 3 months later to verify isolation. Patients entered follow-up only after PVAI (group 1) or PVAI+LAPW (group 2) isolation was proven.At the 1-, 2-, and 3-year follow-up examinations, the rates of freedom from atrial tachyarrhythmia without use of an antiarrhythmic drug were 20%, 15%, and 10% in group 1 and 65%, 50%, and 40% in group 2, respectively (log-rank P.001). The median recurrence-free survival time was 8.5 months (interquartile range 6.5-11.0) in group 1 and 28.0 months (interquartile range 8.5-32.0) in group 2.Proven isolation of the LAPW provides additional benefits over PVAI alone in the treatment of persistent AF and improves procedural outcome at follow-up. However, the ablation strategy of ePVAI+LAPW is still associated with a significant high incidence of very late recurrence of atrial tachyarrhythmia."Outcome of Atrial Fibrillation Ablation After Permanent Pulmonary Vein Antrum Isolation With or Without Proven Left Atrial Posterior Wall Isolation" (LIBERATION). ClinicalTrials.gov Identifier: NCT01660100.

Introduction Electrical isolation of the left atrial appendage (LAA) is an important adjunctive ablation strategy in patients with nonparoxysmal atrial fibrillation (AF). Patients who have impaired LAA contractility following isolation may require long-term oral anticoagulant (OAC) therapy irrespective of their CHADS2 -VASc score. Percutaneous LAA occlusion (LAAO) is a potential alternative to life-long OAC therapy. We aimed to assess the rate of OAC discontinuation and thromboembolic (TE) events following percutaneous LAAO in patients who underwent LAA electrical isolation (LAAI). Methods This is a retrospective two-center study of patients who underwent percutaneous LAAO following LAAI. Patients with at least 3-month follow-up were included in the study. The antithrombotic therapy and TE events at the time of the last follow-up were noted. Results The LAA was successfully occluded in 162 (with Watchman device in 140 [86.4%] and Lariat in 22 [13.6%]). A total of 32 patients had leaks detected on the 45-day transesophageal echocardiogram (TEE); 21 (15%) Watchman and 11 (50%) Lariat cases (P = 0.0001). Two (one Watchman and one Lariat) of the 32 leaks were more than 5 mm. After the 45-day TEE, 150 (92.6%) patients were off-OAC. No TE events were reported in the 150 patients who stopped the anticoagulants. Four (2.47%) patients experienced stroke following the LAAO (three Watchman and one Lariat) procedure while on-OAC, two of which were fatal. At the median follow-up of 18.5 months, 159 (98.15%) patients were off-anticoagulant. Conclusion Up to 98% of patients with LAAI could safely discontinue OAC after undergoing the appendage closure procedure.

Angiotensin-converting enzyme inhibitors (ACEIs) reduce the incidence of atrial fibrillation (AF).The purpose of this study was to assess the impact of upstream ACEI therapy on postablation AF recurrence and hospitalization in patients with low left ventricular ejection fraction (LVEF).Three hundred forty-five consecutive patients undergoing first AF ablation with low LVEF (≤45%) were classified into group 1 (ACEI+, n = 187 [54%], of whom 44 patients [23.5%] had paroxysmal AF [PAF]) or group 2 (ACEI-, n = 158 [46%]; 31 of these 158 patients [19.6%] had PAF). Additionally, 703 consecutive patients with LVEF45% undergoing first AF ablation were included for a secondary analysis to evaluate the effect of ACEI treatment in normal ejection fraction. In group 1, ACEI therapy started ≥3 months before ablation and continued through follow-up.Baseline characteristics were similar except for hypertension, which was significantly more prevalent in ACEI+ (71% vs 51%, P.001). At 24 ± 7 months of follow-up, 109 nonparoxysmal AF patients in group 1 (76%) and 81 (64%) in group 2 (P = .015) were recurrence free. In multivariate analysis, ACEI therapy was an independent predictor of recurrence (hazard ratio for ACEI-, 1.7, 95% confidence interval 1.1-2.7; P = .026]. However, among PAF patients, ACEI use was not associated with ablation success (80% vs 77% in ACEI+ and ACEI-, respectively; P = .82). In the normal-EF population, the success rates between ACEI+ and ACEI- cohorts were similar (71% vs 74%, P = .31). After the index procedure, 17 patients (9.1%) in the ACEI+ group and 28 (17.7%) in the ACEI- cohort (P= .02) required rehospitalization, for a 49% relative risk reduction (relative risk 0.51, 95% confidence interval 0.29-0.90).Preablation use of an ACEI is associated with improvement in ablation outcome in patients with nonparoxysmal AF with low LVEF.

Background— We examined the influence of catheter ablation and periprocedural anticoagulation regimen on trajectory of migraine in atrial fibrillation patients with or without migraine history. Methods and Results— Forty patients with (group 1: 64±8 years; men 78%) and 85 (group 2: 61±10 years; men 73%) without migraine history undergoing atrial fibrillation-ablation were enrolled. Migraine status and quality of life were evaluated using standardized questionnaires. Diffusion magnetic resonance imaging of brain was performed for all at pre and 24 hours post procedure. Catheter ablation was performed with (88, 70%) or without (37, 30%) continuous warfarin treatment. Fifty-four patients (11 and 43 from groups 1 and 2, respectively) had subtherapeutic international normalized ratio on procedure day. At 17±5 months follow-up, from group 1, 25 (63%) reported no migraine, 10 (25%) had P P Conclusions— In most patients, migraine symptoms improved substantially after catheter ablation. Interestingly, the only cases of new migraine and aggravation of pre-existent headache had subtherapeutic international normalized ratio during the procedure and new cerebral infarcts.

Ablation Outcome in Silent Longstanding Persistent AFBackground Impact of catheter ablation on exercise performance, quality of life (QoL) and symptom perception in asymptomatic longstanding persistent AF (LSP-AF) patients has not been reported yet. Methods and Results Sixty-one consecutive patients (mean age 62 ±13 years, 71% males) with asymptomatic LSP-AF undergoing first catheter ablation were enrolled. Extended pulmonary vein antrum isolation plus ablation of complex fractionated atrial electrograms and nonpulmonary vein triggers was performed in all. QoL survey was taken at baseline and 12-months postablation, using Short Form-36 (SF-36). Information on arrhythmia perception was obtained using a standard questionnaire and corroborating symptoms with documented evidence of arrhythmia. Exercise tests were performed on 38 patients at baseline and 5 months after procedure. Recurrence was assessed using event recorder, cardiology evaluation, electrocardiogram, and 7-day holter monitoring. After 20 ± 5 months follow-up, 36 (57%) patients remained recurrence-free off-AAD. Of the 25 patients experiencing recurrence, 21 (84%) were symptomatic. Compared to baseline, follow-up SF-36 scores improved significantly in many measures. For patients with successful ablation, physical component summary (PCS) and mental component summary (MCS) demonstrated substantial improvement (MCS: 64.2 ± 22.3 to 70.1 ± 18.6 [P = 0.041]; PCS: 62.6 ± 18.4 to 70.0 ± 14.4 [P = 0.032]). Postablation exercise study in recurrence-free patients showed significant reduction in resting and peak heart rate (75 ± 11 vs. 90 ± 17 and 132 ± 20 vs. 154.5 ± 36, respectively, P < 0.001), increase in peak oxygen pulse (13.4 ± 3 vs. 18.9 ± 16 mL/beat, Δ5.5 ± 15, P = 0.001), peak VO2/kg (19.7 ± 5 to 23.4 ± 13 mL/kg/min [Δ 3.7 ± 10, P = 0.043]), and corresponding MET (5.6 ± 1 to 6.7 ± 4 [Δ1.1 ± 3, P = 0.03]). No improvement was observed in patients with failed procedures. Conclusion Successful ablation improves exercise performance and QoL in asymptomatic LSP-AF patients.

Ablation Outcome in AF with Concurrent MS and OSA Introduction Metabolic syndrome (MS) and obstructive sleep apnea (OSA) are well-known independent risk factors for atrial fibrillation (AF) recurrence. This study evaluated ablation outcome in AF patients with coexistent MS and OSA and influence of lifestyle modifications (LSM) on arrhythmia recurrence. Methods and Results We included 1,257 AF patients undergoing first catheter ablation (30% paroxysmal AF). Patients having MS + OSA were classified into Group 1 (n = 126; 64 ± 8 years; 76% male). Group 2 (n = 1,131; 62 ± 11 years; 72% male) included those with either MS (n = 431) or OSA (n = 112; no CPAP users) or neither of these comorbidities (n = 588). Patients experiencing recurrence after first procedure were divided into 2 subgroups; those having sporadic events (frequency < 2 months) remained on previously ineffective antiarrhythmic drugs (AAD) and aggressive LSM, while those with persistent arrhythmia (incessant or ≥2 months) underwent repeat ablation. After 34 ± 8 months of first procedure, 66 (52%) in Group 1 and 386 (34%) in Group 2 had recurrence (P < 0.001). Recurrence rate in only-MS, only-OSA, and without MS/OSA groups were 40%, 38%, and 29%, respectively. Patients with MS + OSA experienced substantially higher recurrence compared to those with lone MS or OSA (52% vs. 40% vs. 38%; P = 0.036). Of the 452 patients having recurrence, 250 underwent redo-ablation and 194 remained on AAD and LSM. At 20 ± 6 months, 76% of the redo group remained arrhythmia-free off AAD whereas 74% of the LSM group were free from recurrence (P = 0.71), 33% of which were off AAD. Conclusions MS and OSA have additive negative effect on arrhythmia recurrence following single procedure. Repeat ablation or compliant LSM increase freedom from recurrent AF.

Long-Term Outcome of AF Ablation in MMV PatientsIntroduction 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.

Thyroid hormone (TH) is known to enhance arrhythmogenicity, and high-normal thyroid function is related with an increased recurrence of atrial fibrillation (AF) after catheter ablation. However, the impact of thyroid hormone replacement (THR) on AF ablation is not well known. This study evaluated 1163 consecutive paroxysmal AF patients [160 (14%) on THR and 1003 (86%) without THR] undergoing their first catheter ablation. A total of 146 patients on THR and 146 controls were generated by propensity matching, based on calculated risk factor scores, using a logistic model (age, sex, body mass index, and left atrium size). The presence of non-pulmonary vein (PV) triggers was disclosed by a high-dose isoproterenol challenge (up to 30 μg/min) after PV isolation. Clinical characteristics were not different between the groups. When compared to the control, non-PV triggers were significantly greater in the THR patients [112 (77%) vs. 47 (32%), P

ObjectivesThe aim of this study was to investigate impact of metabolic syndrome (MS) on outcomes of catheter ablation in patients with atrial fibrillation (AF) in terms of recurrence and quality of life (QoL).BackgroundMS, a proinflammatory state with hypertension, diabetes, dyslipidemia, and obesity, is presumed to be a close associate of AF.MethodsIn this prospective study, 1,496 consecutive patients with AF undergoing first ablation (29% with paroxysmal AF, 26% with persistent AF, and 45% with long-standing persistent AF) were classified into those with MS (group 1; n = 485) and those without MS (group 2; n = 1,011). Patients were followed for recurrence and QoL. The Medical Outcomes Study SF-36 Health Survey was used to assess QoL at baseline and 12 month after ablation.ResultsAfter 21 ± 7 months of follow-up, 189 patients in group 1 (39%) and 319 in group 2 (32%) had arrhythmia recurrence (p = 0.005). When stratified by AF type, patients with nonparoxysmal AF in group 1 failed more frequently compared with those in group 2 (150 [46%] vs. 257 [35%], p = 0.002); no difference existed in the subgroup with paroxysmal AF (39 [25%] vs. 62 [22%], p = 0.295). Group 1 patients had significantly lower baseline scores on all SF-36 Health Survey subscales. At follow-up, both mental component summary (Δ5.7 ± 2.5, p < 0.001) and physical component summary (Δ9.1 ± 3.7, p < 0.001) scores improved in group 1, whereas only mental component summary scores (Δ4.6 ± 2.8, p = 0.036) were improved in group 2. In the subgroup with nonparoxysmal AF, MS, sex, C-reactive protein ≥0.9 mg/dl, and white blood cell count were independent predictors of recurrence.ConclusionsBaseline inflammatory markers and the presence of MS predicted higher recurrence after single-catheter ablation only in patients with nonparoxysmal AF. Additionally, significant improvements in QoL were observed in the post-ablation MS population.

Background— Obstructive sleep apnea (OSA) may be associated with pulmonary vein antrum isolation (PVAI) failure. The aim of the present study was to investigate if treatment with continuous positive airway pressure (CPAP) improved PVAI success rates. Methods and Results— From January 2004 to December 2007, 3000 consecutive patients underwent PVAI. Patients were screened for OSA and CPAP use. Six hundred forty (21.3%) patients had OSA. Patients with OSA had more procedural failures ( P =0.024) and hematomas ( P P P =0.001). At the end of the follow-up period (32±14 months), 79% of the non-CPAP and 68% of the CPAP group were free of atrial fibrillation ( P =0.003). Not using CPAP in addition to having non-PV triggers strongly predicted procedural failure (hazard ratio, 8.81; P Conclusions— OSA was an independent predictor for PVAI failure. Treatment with CPAP improved PVAI success rates. Patients not treated with CPAP in addition to having higher prevalence of non-PV triggers were 8 times more likely to fail the procedure.

Introduction: Bipolar voltage mapping detects areas of scar and guides ablation of VT. The role of endocardial unipolar voltage mapping is not well defined. We examined the endo-epicardial substrate in a mixed cohort of patients with structural heard disease (SHD) to determine whether an endocardial unipolar low voltage area predicts the presence and location of an epicardial scar. Results: Data from 24 consecutive patients with SHD (11 ICM, 6 NICM, 3 HCM, 2 ARVC, 1 myocarditis, 1 Brugada) with a detailed (mean points per map 200) combined endocardial-epicardial substrate mapping were retrospectively reviewed. Maps were obtained using a 3D mapping system (CARTO 3) and normal thresholds used were ≤1.5 mV for bipolar voltage, and ≤5.5 (RV) or ≤8.3 mV (LV) for unipolar voltage. Mapping was performed in the LV in 17 patients, in the RV in 6 patients, in both in 1 patient. An endocardial unipolar low voltage area was found in 21/25 maps. In 12/21 maps there was no corresponding epicardial scar, while in 3/4 cases an epicardial scar was detected despite a negative unipolar map (PPV=43%, NPV=25%, P=NS; Fig. 1). In the 9 cases with both positive endocardial unipolar and epicardial bipolar maps, the epicardial scar was found in the corresponding ventricular region of the endocardial low-voltage area, although unipolar area had a tendency to overestimate the area of the scar (115 vs 95 cm 2 ). Conclusion: In this series of patients with SHD, analysis of unipolar voltage maps could not reliably predict the epicardial arrhythmogenic substrate. There is a modest correlation between areas of endocardial unipolar low voltage and epicardial scars (57% of patients with an abnormal unipolar map had a normal epicardial substrate). Moreover, an epicardial substrate cannot be safely excluded based on a normal unipolar endocardial map. Fig. 1 Abnormal bipolar epicardial map (left) with corresponding normal unipolar endocardial map (right) in a patient with ARVC. Pink dots represent area of defragmentation.

Introduction: Focal impulse and rotor modulation (FIRM)-guided ablation targets localized sources that are thought to sustain AF. In previous reports, it has been shown that FIRM is effective in terminating or organizing AF. We sought to evaluate the acute success of FIRM in patients with persistent and LSP AF undergoing ablation in our centers. Methods: This was a multicenter prospective observational study. FIRM was performed alone or before conventional ablation. Rotors were ablated as confirmed by their absence during remapping and acute success was defined as AF termination, organization or slowing 10%. Results: 57 patients were enrolled (mean age 63 ± 10; 7% LSP). Rotors-only ablation was performed in 56% of patients, and preceded conventional ablation in 44%. There were no major periprocedural adverse events. No focal impulses were found, while rotors were present in all patients (3.9 ± 1.2 per patient; 66% in the LA). In the RA, the majority of rotors were in the lateral wall (53%) and in the septum (30%). In the LA, most of the rotors were in proximity of the pulmonary veins (48%), with the second most common locations being around the mitral annulus or in the septum (17% and 13% respectively). Mean procedural time for FIRM only procedures was 226 ± 52 minutes vs a median of 210 (168-240) minutes for FIRM + conventional ablation procedures (p = NS). Overall acute success was achieved in 35% of patients (3% AF termination, 16% AF organization, 16% AF slowing) with a mean RF time to complete FIRM ablation of 30 ± 15 minutes; no difference in acute success was found when comparing persistent to LSP patients (28% vs 50%; p = NS). Conventional ablation following FIRM did not significantly increase the rate of acute success (1 additional patient converted to sinus rhythm during pulmonary vein isolation). Conclusion: Rotors were present in all patients undergoing ablation for non-paroxysmal AF, most commonly the right atrial lateral wall, septum or around the pulmonary veins. Their ablation was not effective in obtaining AF organization/termination during the procedure.

Introduction: We sought to investigate the characteristics and outcomes of patients who underwent RF ablation of PM ventricular arrhythmias (VA) in our center. Results: 26 patients were included, median age was 66 years (16 to 85), 46% female, all with normal LVEF. PM VAs were PVCs in 68% patients, and PVC + VT in 32%. Site of origin was the LV infero-septal PM in 73%, LV antero-lateral PM in 15% and right ventricular RV septal PM in 12%. 46% of patients showed other VAs in addition to the one originating from the PMs; in 33% of these patients, additional VAs were 2 or more. These VAs were mostly PVCs (92%), localized in the LVOT (64% - 56 % in the basal LV and 44% in the aortic cusps) and the septal RVOT (36%). The only additional VT was fascicular. All the PMs and mappable additional VAs were ablated with RF energy through an irrigated catheter and the aid of ICE; a remote magnetic navigation system (RMS) was used in half of the procedures. In one case, PVC suppression required additional epicardial ablation. Major complications occurred in 2 patients (8%): 1 pericardial effusion (the patient underwent ablation of a crista terminalis premature atrial complex in the same procedure) and 1 pseudoaneurysm. Acute success (PM VA suppression/non-inducibility) was achieved in 96% of patients (the patient with pericardial effusion could be anticoagulated further and the procedure was stopped). After a median follow-up period of 8 (4-14) months, long-term success (no PM VT recurrence or PVC burden reduced by 80% off antiarrhythmic drugs) was 92% after a single procedure, 96% after repeat procedures. When considering additional VAs, the only recurrence was a parahisian RVOT PVC. No difference in acute or overall long-term success was observed when comparing RMS-guided vs standard procedures (respectively 92% vs 100 % and 100% vs 92%; P = NS). Conclusion: PM VAs are most commonly PVCs originating from the LV infero-septal PM and are frequently (48%) associated with an additional ventricular focus (LVOT > RVOT >> fascicular VT). RF ablation is safe and effective in eliminating or significantly reduce the burden of PM VAs, as well the extra-PM foci that are commonly encountered in this population. RMS guided ablation is not inferior to standard ablation in this subset of patients.

The impact of amiodarone on ablation outcome in longstanding persistent atrial fibrillation (LSPAF) patients is not known yet.The purpose of this study was to assess the effect of amiodarone on procedural-outcomes in LSPAF patients undergoing catheter ablation.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.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.Periprocedural continuous amiodarone was associated with higher organization rate and lower radiofrequency ablation rate. However, masking non-PV triggers increased the late recurrence rate.

Introduction: Earlier studies have demonstrated that some AF patients develop spontaneous atrial scarring that leads to genesis and perpetuation of the arrhythmia. However, it is still unclear why it happens in some and not in others. Therefore, we hypothesized that the atrial scar phenotype is associated with certain specific genetic variants and examined the relationship between AF-related single-nucleotide polymorphisms (SNP) and left atrial scar. Methods: Four hundred AF patients (67% male, 62±12 year, left atrial size 45.3±7 mm, 64% non-paroxysmal) undergoing catheter ablation were prospectively enrolled at our center. DNA extraction and genotyping for 16 AF-associated SNPS identified by GWAS study were performed from the collected blood samples using Qiagen QiaAMP 96 well blood kit and TaqMan assay respectively. Three hundred seventy-two DNA samples were available for genotyping. The Hardy-Weinberg equilibrium was assessed using Chi-square analyses. Multivariable logistic model was utilized to identify predictors of LA scar after adjusting for age, gender, LA size, hypertension and diabetes mellitus and odds ratio (OR) and 95% confidence intervals were computed. Results: Of all 16 SNPs, rs3807989 showed a strong inverse association with LA scar at univariate analysis (0.54 [0.348-0.89] p= 0.014) in the overall population. After adjustment for covariates, the association became highly significant indicating a 50% reduction in scar risk (OR 0.50 (0.30-0.83) p=0.007). When stratified by type of AF, rs3807989 genotype predicted a substantially stronger 69% risk-reduction in the non-PAF population (OR 0.31 (0.15-0.62) p=0.0009). Conclusion: The SNP, rs3807989 on chromosome 7p31, was demonstrated to be associated with reduced risk of left atrial scar formation in AF patients. This genetic variant is located in close proximity to the caveolin-1 gene which is known to have an anti-fibrotic role by inhibiting transforming growth factor-β1, a key mediator in the fibrosis process. Therefore, it can be postulated that by some unknown mechanism the candidate chromosomal variant potentially upregulates caveolin-1 function resulting in attenuation of fibrosis and scar formation.

Introduction: Earlier evidences support the origin of ectopic beats from non-pulmonary vein (non-PV) areas that initiate and maintain AF and elimination of these triggers is known to provide better arrhythmia-free survival. Of the different types, non-paroxysmal AF (NPAF) are more prevalently associated with non-PV drivers. Although emerging data on myocytes-fibroblast interactions provide some insight into the pathophysiology of non-PV triggers, the exact mechanism of origin of these ectopic foci is still unknown. Therefore, we examined the association of several AF-specific genetic variants with prevalence of non-PV triggers in NPAF patients undergoing catheter ablation. Methods: Four hundred AF patients (67% male, 62±12 year, left atrial size 45.3±7 mm, 64% non-paroxysmal) undergoing catheter ablation were prospectively enrolled at our center. DNA extraction and genotyping for 16 AF-associated SNPS from collected blood samples were performed using Qiagen QiaAMP 96 well blood kit and TaqMan assay respectively. Three hundred seventy-two DNA samples were available for genotyping. Multivariate logistic regression analysis (adjusted covariates: age, gender, LA size, hypertension and diabetes) was used for assessing predictive role of individual SNP; and logistic kernel-machine approach was applied to test the cumulative effect of multiple SNPs as a group with non-PV triggers. Result: In the non-paroxysmal AF population, significant allelic association was detected between non-PV triggers and rs6599230 (OR 0.57 [95% CI 0.31-0.88], p=0.042) and rs1448817 (OR 1.82 [95%CI 1.12-3.40], p=0.034). Interestingly, rs6599230 suggested a protective effect with 43% risk reduction while rs1448817 was an independent predictor of higher risk of developing non-PV triggers. Conclusion: Our results identified predictive association of two genetic variants, rs6599230 and rs1448817, with non-PV triggers in non-paroxysmal AF patients. Interestingly, the association was distinctive. The SNP, rs6599230 located in close proximity to SCN5A gene, was found to have a protective effect against development of arrhythmogenic triggers in the extra-PV sites whereas rs1448817 on chromosome 4q25 increased the risks of having non-PV triggers.

Metabolic syndrome (MS) and obstructive sleep apnea (OSA) are well-known independent risk factors for atrial fibrillation (AF) recurrence. This study evaluated ablation outcome in AF patients with coexistent MS and OSA and influence of lifestyle modifications (LSM) on arrhythmia recurrence.We included 1,257 AF patients undergoing first catheter ablation (30% paroxysmal AF). Patients having MS + OSA were classified into Group 1 (n = 126; 64 ± 8 years; 76% male). Group 2 (n = 1,131; 62 ± 11 years; 72% male) included those with either MS (n = 431) or OSA (n = 112; no CPAP users) or neither of these comorbidities (n = 588). Patients experiencing recurrence after first procedure were divided into 2 subgroups; those having sporadic events (frequency2 months) remained on previously ineffective antiarrhythmic drugs (AAD) and aggressive LSM, while those with persistent arrhythmia (incessant or ≥2 months) underwent repeat ablation. After 34 ± 8 months of first procedure, 66 (52%) in Group 1 and 386 (34%) in Group 2 had recurrence (P0.001). Recurrence rate in only-MS, only-OSA, and without MS/OSA groups were 40%, 38%, and 29%, respectively. Patients with MS + OSA experienced substantially higher recurrence compared to those with lone MS or OSA (52% vs. 40% vs. 38%; P = 0.036). Of the 452 patients having recurrence, 250 underwent redo-ablation and 194 remained on AAD and LSM. At 20 ± 6 months, 76% of the redo group remained arrhythmia-free off AAD whereas 74% of the LSM group were free from recurrence (P = 0.71), 33% of which were off AAD.MS and OSA have additive negative effect on arrhythmia recurrence following single procedure. Repeat ablation or compliant LSM increase freedom from recurrent AF.

Metabolic syndrome (MS), a pro-inflammatory state with hypertension, diabetes, dyslipidemia and obesity is presumed to be a close associate of atrial fibrillation (AF). However, the exact mechanism by which MS facilitates perpetuation of AF is yet to be fully understood. Moreover, the impact of the components of MS as well as MS as a group, on ablation-outcome in AF is not clearly elucidated until now. This review has compiled the results from major studies that have looked into those risk factors and defined their significance in influencing ablation-outcome in AF. It has also overviewed the impact of life-style changes that might improve the success rate of AF-ablation by effectively addressing the different constituents of MS.

Post-infarction patients with severe left ventricular dysfunction are at high risk of sudden cardiac death. Antiarrhythmic therapy does not improve survival in such patients and, therefore, implantable cardioverter defibrillators (ICD) emerged as treatment of choice for both primary and secondary prevention of mortality after myocardial infarction (MI). The MADIT (Multicenter Automatic Defibrillator Implantation Trial) (1), and MUSTT (Multicenter Unsustained Tachycardia Trial) trials (2) were the first primary prevention ICD trials documenting a substantial reduction in mortality with an ICD in postinfarction patients with depressed ejection fraction, nonsustained ventricular tachycardia, and inducible sustained ventricular tachycardia. The MADIT II trial broadened the indications for prophylactic ICD use in post-infarction patients with ejection fraction of 30% or less without a requirement for additional risk stratification (3). The benefit from ICD therapy in patients with low ejection fraction was recently confirmed by results from the SCD-HeFT (Sudden Cardiac Death in Heart Failure) (4) and COMPANION (Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure) trials (5).

Obesity increases the risk of atrial fibrillation (AF), and AF seriously impairs the quality of life (QoL). However, it is not known whether body mass index (BMI) has any direct influence on QoL in AF.To study the association between baseline BMI and QoL improvement in patients with AF following catheter ablation.Six hundred sixty patients with AF (62 ± 10 years, male 69%, paroxysmal AF 27%, persistent AF 31%, long-standing persistent AF 42%) made up the study population. On the basis of the baseline BMI, patients were categorized into 2 groups: normal (BMI25) and overweight/obese (BMI ≥ 25). The QoL survey was done at baseline and at 12-month postablation by using the Medical Outcomes Study Short Form-36 (SF-36), Beck Depression Inventory (BDI), Hospital Anxiety and Depression (HAD) scale, and State-Trait Anxiety Inventory (STAI).At baseline, dyslipidemia, hypertension, diabetes, coronary artery disease, and large left atrium had higher prevalence in the overweight/obese population. In addition, the preprocedure QoL scores on the SF-36, HAD scale, and STAI were significantly lower in this group than in the normal-BMI group. At the 12-month postablation assessment, no significant improvement in QoL score was noted in the normal-BMI group. However, in the overweight/obese group, QoL scores improved significantly in all scales, except the physical functioning and bodily pain categories of SF-36. Long-term ablation success was not different across the groups (69% normal BMI, 63% high BMI, log-rank P = .109). Patients with successful ablation showed significant improvement in QoL scores compared with those who failed. The multivariable analysis revealed the baseline QoL score and BMI ≥ 25 to be independent predictors of QoL improvement.Obese patients with AF tend to have a better postablation QoL outcome than do their nonobese counterparts.

Baseline BNP Predicts Ablation Outcome in Male AF Patients. Background: Close association between atrial fibrillation (AF) and brain natriuretic peptide (BNP) has been demonstrated by several studies. Important gender differences exist in AF patients including a higher plasma BNP level in women. Therefore, it is imperative to evaluate the relationship between AF and BNP separately in men and women. Objective: This study examined possible gender-specific role of BNP in predicting procedure outcome in AF patients undergoing catheter ablation. Method: The study population included 568 consecutive patients (age 62 ± 10, male 73%, paroxysmal 25%, persistent 38%, and long-standing persistent AF 37%) undergoing AF ablation, who had structurally normal heart and left ventricular ejection fraction ≥45%. Baseline BNP was measured in all. Patients were grouped into “normal” and “high” BNP based on gender-specific cut-off values (

Background The proximity of the phrenic nerve (PN) to cardiac tissue relevant to arrhythmias may increase the risk of PN injury. Strategies for preventing PN injury in the pericardial space are limited. Objective The purpose of this study was to compare methods for separating the PN from the epicardial surface in order to prevent PN injury. Methods Eight patients referred for epicardial ablation of arrhythmias were enrolled in the study. All patients required ablation near the PN. Endocardial and epicardial access was obtained in all patients. A three-dimensional mapping system was used to guide mapping and ablation. All patients underwent epicardial catheter ablation. Pacing via the ablation catheter identified the location of the PN. In order to prevent PN injury, four new strategies were tested in each patient. We sought to increase the distance between the epicardium and the PN by (1) placing a large-diameter balloon between the nerve and the myocardium, (2) introducing saline in steps of 20 ml until PN capture was lost or blood pressure dropped below 60 mmHg, (3) introducing air until PN capture was lost or blood pressure dropped below 60 mmHg, or (4) introducing a combination of saline and air until PN capture was lost or blood pressure dropped below 60 mmHg. Results At each step, epicardial pacing was performed to assess for PN stimulation. The combination of air and saline resulted in the greatest decrease of PN stimulation. Saline only failed in all cases. Air only and balloon placement were infrequently successful. Conclusion Controlled and progressive inflation of air and saline together with careful monitoring of hemodynamic parameters appears to be the best strategy for preventing PN injury during epicardial ablation. Placement of a large balloon in the appropriate location can be difficult.

Atrial fibrillation is a common arrhythmia associated with significant morbidity, including angina, heart failure, and stroke. Medical therapy remains suboptimal, with significant side effects and toxicities, and a high recurrence rate. Catheter ablation or modification of the atrioventricular node with pacemaker implantation provides rate-control but exposes patients to the hazards associated with implantable devices and does nothing to reduce the risk for stroke. Pulmonary vein antrum isolation offers a nonpharmacologic means of restoring sinus rhythm, thereby eliminating the morbidity of atrial fibrillation and the need for antiarrhythmic drugs.