Epicardial Ventricular Tachycardia Ablation Research Articles

Epicardial catheter ablation of ventricular tachycardia in patients of acm - from a university hospital report in switzerland

Abstract Background Arrhythmogenic left ventricular cardiomyopathy (ALVC) as a subtype of arrhythmogenic cardiomyopathy (ACM) is increasingly being recognized. Cardiac magnetic resonance (CMR) has emerged as the primary imaging modality for the diagnosis of ACM. In patients with right-dominant ACM (ARVC) and recurrent sustained ventricular tachycardia (VT), endocardial +/-epicardial ablation yields good clinical outcomes in the long-term. However, studies on VT ablation in ACM with LV involvement are scarce. Purpose We sought to investigate clinical outcomes of VT ablation in ACM patients with LV involvement. Methods The study included patients from the Zurich ACM Registry who met 2020 "Padua Criteria" for ACM and underwent VT ablation between January 2018 and July 2023. Epicardial ablation was performed in patients with recurrent sustained VT despite endocardial ablation, those lacking and endocardial substrate or if the ECG of the VT / substrate on CMR was suggestive of an epicardial origin. Catheter ablation was guided by activation/entrainment mapping for mappable VT, and pace mapping/voltage mapping during sinus rhythm for unmappable VT. Consecutive follow-up of all patients was performed according to our protocol. Results Twenty-one ACM patients underwent n=24 VT ablation procedures. Of those 20 patients, 6 patients (30%) had LV involvement on CMR. Eight (33%) patients underwent epicardial +/- endocardial ablation. Among patients receiving epicardial ablation, 3 patients (38%) had LV involvement. These three underwent a single ablation procedure, which was epicardial only. Total follow-up was 30 months (range 4-43). Three-month sustained VT/VF recurrence rates were 12% in the ACM group with LV involvement vs 25% in ACM without LV involvement. All patients with sustained VT/VF recurrence underwent repeat ablation via an epicardial approach within 3 months and were free of sustained VT/VF thereafter during a median follow-up of 12 months. One-year recurrence rate did not differ between ACM patients with LV involvement vs. without LV involvement (7.7% vs 8.3%, P＝0.117). Seven out of eight epicardial ablations achieved freedom from VT/VF after one-year follow-up. One ARVC patient with previous endocardial ablation had recurrent VT one month after epicardial ablation, which was free of VT after Flecainide combined with beta-blocker. No significant differences were found in the use of beta-blockers and antiarrhythmic drugs between both groups (ACM with LV involvement vs. without LV involvement) at baseline and during one-year follow-up. Conclusions Single or adjuvant epicardial substrate ablation of VT in arrhythmogenic cardiomyopathy is promising in terms of postprocedural VT free survival, especially in patients with left ventricular involvement demonstrated by CMR.Figure 1Figure 2

Long-term outcomes of ventricular tachycardia ablation in patients with ischemic and non-ischemic cardiomyopathy: a propensity-score matched analysis

Abstract Background Catheter ablation (CA) has been shown to be effective in the treatment of ventricular tachycardia (VT). Although some observational data suggest that patients with non-ischemic cardiomyopathy (NCIM) have less favorable clinical outcomes when compared to those with an ischemic etiology (ICM), direct comparisons are scarcely reported. We aimed to compare the outcomes of VT ablation in a propensity score-matched population of ICM or NICM patients. Methods Single-center observational registry including 246 consecutive patients with ischemic (ICM, N=166) and non-ischemic cardiomyopathy (NICM, N=80) who underwent drug-resistant VT ablation from 2012 to 2023. A propensity score (PS) was used to match patients in a 1:1 fashion according to the following variables: age, sex, left ventricular ejection fraction (LVEF), NYHA class, electrical storm (ES) at presentation, and previous endocardial VT ablation. The outcomes of interest were VT-free survival and all-cause mortality. Results The PS yielded two groups of 71 patients each (mean age 63±10 years, 92.3% male, mean LVEF 35±10%, 35.9% with ES at presentation, and 23.2% with previous ablation), well matched for baseline characteristics. Those with NICM were more likely to undergo epicardial or combined VT ablation (43.7% vs. 9.9%, P<0.001). The procedural complication rate was low (4.9%, N=7) and similar between groups (P>0.05). During a median follow-up of 27 (IQR 15–45) months, patients with NICM had a significantly lower VT-free survival (53.5% vs. 69.0%, log-rank P=0.037), although there were no differences regarding all-cause mortality (22.5% vs. 16.9%, log-rank P=0.245) – Figure. Multivariate analysis identified NICM (HR 2.34 [95% CI 1.32–4.14], P=0.004), NYHA class III/ IV (HR 2.11 [95% CI 1.11–4.04], P=0.024), and chronic kidney disease (HR 2.23 [95% CI 1.25–3.96], P=0.006), as independent predictors of VT recurrence. Non-inducibility of any VT immediately after ablation was associated with significantly lower rates of VT recurrence (22.8%/ year vs. 42.4%/ year, log-rank P=0.03). Conclusion NCIM patients are at increased risk of VT recurrence after ablation, although long-term mortality was similar to ICM in a propensity-matched cohort. Non-inducibility of any VT after CA is associated with better outcomes.Figure

Digital health in the electrophysiological lab: Initial experience, safety and feasibility using remote support for arrhythmia ablation-Results of REMOTE-VA study

Abstract Background In most electrophysiology (EP) labs, electroanatomical mapping (EAM) systems are operated on site by qualified staff or field technical engineers (FTE). Due to lack of skilled personnel, the FTE usually must travel between different hospitals and procedures must be planned in advance. Ablation of ventricular arrhythmias (VA) represents the most complex procedure in the field. The use of remote support (RS) to guide complex EP procedures has the potential to increase flexibility, reduce travel times and maximise healthcare resources. Purpose To evaluate the safety and feasibility of RS as compared to on-site support guided catheter ablation procedures for VA. Methods All patients undergoing ventricular tachycardia (VT) or premature ventricular complex (PVC) ablation using remote support were included. The electronical system of the hospital was searched for 30 days postprocedural emergency department (ED) visits, unplanned ambulatory presentations, and readmissions. RS guided three-dimensional (3D) mapping was achieved by connecting the EAM software with an integrated audio-visual solution for remote support. Internet connection-based headphones and high-resolution cameras ensured the communication between the operator and the FTE, who worked exclusively from home office. The control group consisted of an equal number of patients matched for the type of procedure and undergoing on-site guided procedures. All ablations were performed using high density 3D mapping, as per institutional standard. Results Between October 2022 and October 2023, a total of 25 patients underwent VT (32%) or PVC ablation in our centre using RS and were compared to 25 patients undergoing the same procedures under on-site guidance. In the RS group one patient underwent epicardial VT ablation and another one bipolar ablation for VT Storm. The demographic data were similar between the groups. The median procedure time was 120 (93, 143) minutes in the RS group and 112 (95, 138) minutes in the control group (p=0.95), while the fluoroscopy time was 11.4 (7.0, 14.0) and 7.26 (5.0, 10.9) minutes respectively (p=0.08). The procedural success was achieved in 96% procedures in the RS group and in 100% in the control group. No technical issues or changes to on-site support were reported. One minor intraprocedural complication was noted among the control patients, while 24% of the patients in each group developed minor complications until discharge. Two patients in the RS group and one in the control group had ED visits, while only one patient in the control group had an unplanned ambulatory presentation. One unplanned readmission was reported in the control group (Table 1). Conclusions Even in the most complex procedures including epicardial ablation, the use of RS was feasible and safe in this single centre study. This approach has the potential to increase the feasibility in case of emergency procedures, reduce travel times, and maximise healthcare resources.

Epicardial ventricular tachycardia ablation: safety and efficacy of access and ablation using low-iodine content.

Epicardial ablation has become an integral part of the treatment of ventricular tachycardias (VT). This study reports the safety of epicardial access as well as the efficacy of epicardial ablation of structural heart disease in a tertiary single-center experience. Between January 2016 and February 2022, consecutive patients undergoing an epicardial access for VT ablation were included. Different puncture techniques and occurrence of epicardial access-related complications as well as the safety of ablation using non-ionic 5% dextrose in water (D5W) compared to standard 0.9% normal saline (NS) irrigation were analyzed. VT recurrence rates during a mean follow-up of 37 ± 23months were reported. In total, 197 patients undergoing a total of 239 procedures were included (59.8 ± 15.3years, 86% males). A total of 154 patients (78%) had non-ischemic cardiomyopathies with a mean LVEF of 37 ± 14. Anterior-oriented epicardial access was aimed for in all cases and was successful in 217 (91%) of all procedures, whereas access was achieved in 19 procedures (8%) only using an inferior oriented access and in three procedures (1%) using surgical access due to severe adhesions or anatomical requirements. Overall epicardial puncture-related complications occurred in 18 (8%) of all procedures with minor pericardial bleeding in nine, pericardial tamponade in one, pneumothorax in five, pneumopericardium in one, and abdominal puncture in two cases. Presence of adhesions could be identified as the only independent predictor of epicardial access-related complications. D5W was used in 79 cases and regular 0.9% saline in 117 procedures. No differences were seen regarding acute ablation success or complications. During follow-up, 47% of all patients were free from any VTs (56% D5W vs. 40% NS; log-rank p = 0.747) and 92% of clinical VTs (98% D5W vs. 91% NS; log-rank p = 0.139). In this large single-centre experience, epicardial access and ablation were safe and feasible. Although long-term clinical VT recurrence rates were low, overall VT recurrences as well as mortality were high advocating for a highly experienced, interdisciplinary approach including intense management of underlying cardiac disease/heart failure. Routine usage of D5W was safe and associated with comparable short- or long-term clinical or overall VT freedom.

Feasibility of carbon dioxide insufflation and impact on epicardial approach utilization for ventricular tachycardia ablation in a midvolume referral center

BackgroundEpicardial access is often crucial for successful ventricular tachycardia (VT) ablation, but it is often burdened by significant procedural risk. Intentional coronary vein exit and intrapericardial CO2 insufflation (EpiCO2) can facilitate subxiphoid pericardial access. ObjectiveThis prospective study aimed to assess procedural feasibility, safety, and impact of the introduction of intrapericardial CO2 insufflation for epicardial access in a referral center for VT ablation. MethodsAll consecutive patients treated with epicardial VT ablation between November 2022 and January 2024 with the EpiCO2 technique at Pisa University Hospital were prospectively enrolled and compared in terms of feasibility, efficiency, and safety with a local retrospective cohort of patients treated with subxiphoid dry puncture between July 2018 and October 2022. ResultsTwenty-two consecutive patients (90.9% male; mean age, 54.3 years) underwent VT ablation with EpiCO2 during the study period. Epicardial access was achieved in all patients; median time from coronary sinus (CS) cannulation to epicardial access was 33 minutes. Intentional vein exit was successful in all cases, whereas CO2 insufflation was not feasible in 1 patient. There were no major complications and no significant bleeding. Since EpiCO2 introduction, epicardial approach utilization increased from 17.8% to 40% of all VT procedures. Comparison with 20 standard dry approach epicardial ablations showed no significant differences in terms of total procedural duration (322.5 [interquartile range, 296.75–363.75] minutes vs 359 [interquartile range, 323–409] minutes; P = .08). ConclusionIn our single-center experience, EpiCO2 was feasible and safe and led to significant increase in procedural volume without affecting total procedural time compared with standard dry puncture.

Epicardial ablation of an endomyocardial ventricular tachycardia in the setting of Covid-19 infection

Epicardial ablation of an endomyocardial ventricular tachycardia in the setting of Covid-19 infection

Successful open chest intraoperative epicardial ventricular tachycardia mapping and ablation during the HeartMate-3 left ventricular assist device implantation in Taiwan

Successful open chest intraoperative epicardial ventricular tachycardia mapping and ablation during the HeartMate-3 left ventricular assist device implantation in Taiwan

Cryothermal energy demonstrates shorter ablation time and lower complication rates compared with radiofrequency in surgical hybrid ablation for recurrent ventricular tachycardia

Recurrent ventricular tachycardia (VT) after prior endocardial catheter ablation(s) presents challenges in the setting of prior cardiac surgery where percutaneous epicardial access may not be feasible. The purpose of this study was to compare the outcomes of cryothermal vs radiofrequency ablation in direct surgical epicardial access procedures. We performed a retrospective study of consecutive surgical epicardial VT ablation cases. Surgical cases using cryothermal vs radiofrequency ablation were analyzed and outcomes were compared. Between 2009 and 2022, 43 patients underwent either a cryothermal (n = 17) or a radiofrequency (n = 26) hybrid epicardial ablation procedure with direct surgical access. Both groups were similarly matched for age, sex, etiology of VT, and comorbidities with a high burden of refractory VT despite previous endocardial and/or percutaneous epicardial ablation procedures. The surgical access site was lateral thoracotomy (76.5%) in the cryothermal ablation group compared with lateral thoracotomy (42.3%) and subxiphoid approach (38.5%) in the radiofrequency group, with the remainder in both groups performed via median sternotomy. The ablation time was significantly shorter in those undergoing cryothermal ablation vs radiofrequency ablation (11.54 ± 15.5 minutes vs 48.48 ± 23.6 minutes; P < .001). There were no complications in the cryothermal ablation group compared with 6 patients with complications in the radiofrequency group. Recurrent VT episodes and all-cause mortality were similar in both groups. Hybrid surgical VT ablation with cryothermal or radiofrequency energy demonstrated similar efficacy outcomes. Cryothermal ablation was more efficient and safer than radiofrequency in a surgical setting and should be considered when surgical access is required.

Dry suction water seal system for management of pericardial fluid during epicardial ablation.

Epicardial ablation is an important approach in the management of patients with complex ventricular arrhythmias. Irrigated ablation catheters present a challenge in this potential space due to fluid accumulation that can cause hemodynamic compromise, requiring frequent manual fluid aspiration. In this series, we report our initial experience with the use of a dry suction water seal system for pericardial fluid management during epicardial ablation. Consecutive patients undergoing epicardial ventricular tachycardia (VT) ablation at a single center were included. All patients underwent epicardial access via a subxiphoid approach with a single operator. A deflectable sheath was advanced into the pericardial space, and the side port was attached to a dry suction water seal system attached to wall suction at -20 mmHg. Procedural information including patient characteristics, outcomes, and adverse events. After a period of initial experience, pericardial fluid infusion and aspiration volumes were recorded. Eleven patients were included in this series. All patients underwent epicardial ablation with complete success achieved in 8 of the 11 patients and partial success in the remaining patients. Pericardial fluid intake ranging from 485 to 3050 mL with aspiration of 350-3050 mL using the dry suction water seal system. No adverse events occurred. Dry suction water seal drainage systems can provide a safe strategy for efficient pericardial fluid management during epicardial VT ablation, potentially shortening procedure duration.

The infrastructure of electrophysiology centers impacts the management of cardiac tamponade-Results from a national survey.

Although electrophysiological (EP) centers have institutional standards, evidence on management of cardiac tamponade is lacking. A physician-based survey was conducted by sending out questionnaires to all hospitals in Germany performing EP procedures. To evaluate the infrastructure of EP centers and the impact of center volume and onsite cardiac surgery on the management of cardiac tamponade, the results of the survey were analyzed for low-volume (0-250 procedures per year), mid-volume (250-500 procedures), and high-volume (>500 procedures) centers, as well as for centers with and without onsite cardiac surgery. A total of 341 centers were identified and 189/341 (55%) returned data sets were analyzed. Most types of EP procedures are performed across all kinds of centers. Ablation of ventricular tachycardia (VT) is concentrated in higher volume centers and in centers with onsite cardiac surgery. None of the participating low-volume centers and only 13% of centers without onsite cardiac surgery responded to performing epicardial VT ablation. Irrespective of center volume and onsite cardiac surgery, neither body mass index nor age was reported to be an exclusion criterion for ablation procedures. Higher volume centers and centers with onsite cardiac surgery more often have dedicated EP laboratories and EP-nursing teams. Also, differences regarding periprocedural safety precautions and management of cardiac tamponade were found for low-, mid-, and high-volume centers, as well as for centers with and without onsite cardiac surgery. While center volume and onsite cardiac surgery do not impact patient selection, there are differences in ablation spectrum, infrastructure, periprocedural safety precautions, and treatment of tamponade.

Intraoperative open chest epicardial high-density mapping and ablation for refractory ventricular tachycardia at time of magnetically levitated left ventricular assist device implantation

Intraoperative open chest epicardial high-density mapping and ablation for refractory ventricular tachycardia at time of magnetically levitated left ventricular assist device implantation

Patient Selection, Techniques, and Complication Mitigation for Epicardial Ventricular Tachycardia Ablation.

Percutaneous epicardial ventricular tachycardia ablation can decrease implanted cardioverter defibrillator shocks and hospitalizations; proper patient selection and procedural technique are imperative to maximize the benefit-risk ratio. The best candidates for epicardial ventricular tachycardia will depend on history of prior ablation, type of cardiomyopathy, and specific electrocardiogram and cardiac imaging findings. Complications include hemopericardium, hemoperitoneum, coronary vessel injury, and phrenic nerve injury. Modern epicardial mapping techniques provide new understandings of the 3-dimensional nature of reentrant ventricular tachycardia circuits across cardiomyopathy etiologies. Where epicardial access is not feasible, alternative techniques to reach epicardial ventricular tachycardia sources may be necessary.

Abstract 11905: Dexmedetomidine for Sedation During Epicardial Ablation for Ventricular Tachycardia: A Single-Center Experience

Introduction: Epicardial ablation of ventricular tachycardia (VT) is mainly performed under general anesthesia (GA). However, GA lowers blood pressure, may interfere with arrhythmia induction, and the use of muscle relaxants precludes identification of the phrenic nerve. Moreover, an anesthesiologist's is required during GA for the whole procedure, which may not always be possible. Hypothesis: The aim of there study was to evaluate the feasibility and safety of epicardial VT ablations under conscious sedation using dexmedetomidine. Methods: Between 2018 and 2022, all patients who underwent epicardial VT ablation under dexmedetomidine infusion were prospectively enrolled. All patients received premedication with paracetamol 1 g (acetaminophen 10 mg/ml) and ketorolac 30 mg. Sedation protocol included an i.v. bolus of midazolam (0.03-0.05 mg/kg) followed by continuous infusion of dexmedetomidine (0.2-0.7 mcg/kg/h). In addition, an i.v. fentanyl bolus (0.7-1.4 mcg/kg) was given for short-term analgesia, followed by a second dose after 30-45 minutes. Sedation-related complications were: hypoxia (S02&lt;90%), severe hypotension (MAP&lt;60 mmHg), and bradycardia (HR &lt;45 b/m). Results: Seventy-one patients with drug-refractory recurrent VT underwent epicardial or endo-epi ablation under conscious sedation. Standard percutaneous sub-xiphoid access was attempted in all patients. in 2 patients the procedure was switched to GA because of intractable pain during epicardial catheter's manipulation. Data from 69 patients were analyzed. Mean age was 65.4±12.1 years and 66.6% of patients were males. Forty-seven patients (68.1%) had non-ischemic cardiomyopathy, 13 patients (18.9%) had ischemic-cardiomyopathy, and 9 patients (13%) had myocarditis. Procedural-related complications occurred in five patients (7.2%), one transient phrenic nerve palsy, two pericarditis, and two vascular complications. No severe adverse events related to the sedation occurred. Conclusions: Prompt availability of anesthesia support remains crucial for epicardial VT ablation. Continuous infusion of dexmedetomidine in addition to midazolam and fentanyl seems to be a safe and effective sedation protocol in patients undergoing epicardial VT ablation.

Abstract 14704: Comparison of Anticoagulation Strategies for Epicardial Access in Ventricular Tachycardia Catheter Ablation

Introduction: Percutaneous epicardial access (EpiAcc) is frequently required for endo-epicardial ablation of ventricular tachycardia (VT), especially in ischemic cardiomyopathy, where it has been demonstrated to increase success rate. For patients who have indications for chronic oral anticoagulation (OAC), this often poses a challenge due to potential risks of procedural complications. We sought to assess the safety and outcomes of epicardial VT ablation on uninterrupted OAC compared to off anticoagulation. Methods: In this multicenter study, we retrospectively analyzed patients with ischemic cardiomyopathy and VT who underwent endo-epicardial ablation with EpiAcc. The study group included patients who underwent ablation either under uninterrupted OAC or off anticoagulation. Procedural data, outcomes, and complication rates were analyzed for comparison of both groups. Results: Overall, we analyzed 135 patients who underwent VT ablation via EpiAcc; 55 under full-dose uninterrupted AC and 80 off AC. There was no difference in procedure-related complications between both groups (1.8% vs 2.5%, p=0.09). There was no major bleeding requiring transfusion in any group. There was no difference in risk of cardiac tamponade between both groups (0% vs 0%, p=1). The rate of groin hematoma was 1.8% vs 1.3%, p=0.087). No thromboembolic events were reported. Conclusion: Epicardial VT ablation on uninterrupted OAC is a safe alternative to off AC, with no additional risk of life-threatening complications, thus preventing the possibility of thromboembolic events in patients who have an indication for chronic AC. 1

Dexmedetomidine for sedation during epicardial ablation for ventricular tachycardia: a single-center experience.

Epicardial approach to ventricular tachycardia (VT) ablation is mainly performed under general anesthesia (GA). Although catheter manipulation and ablation in the epicardial space could be painful, GA lowers blood pressure and may interfere with arrhythmia induction and mapping, and the use of muscle relaxants precludes identification of the phrenic nerve (PN). Moreover, an anesthesiologist's presence is required during GA for the whole procedure, which may not always be possible. Therefore, we evaluated the feasibility and safety of epicardial VT ablations performed under conscious sedation using dexmedetomidine in our center. Between January 2018 and January 2022, all patients who underwent epicardial VT ablation under continuous dexmedetomidine infusion were prospectively included in the study. All patients received premedication 30min before the epicardial puncture with paracetamol (acetaminophen 10mg/ml) 1000mg and ketorolac 30mg. Sedation protocol included an intravenous bolus of midazolam hydrochloride (0.03-0.05mg/kg) followed by continuous infusion of dexmedetomidine (0.2-0.7 mcg/kg/h). In addition, an intravenous fentanyl citrate bolus (0.7-1.4 mcg/kg) was given for short-term analgesia, followed by a second dose repeated after 30 to 45min. Sedation-related complications were defined in case of respiratory failure, severe hypotension, and bradycardia requiring treatment. Sixty-nine patients underwent epicardial or endo-epi VT ablation under conscious sedation and were included in the analysis. The mean age was 65.4 ± 12.1years; forty-six patients were males (66.6%). All patients had drug-refractory recurrent VT. Forty-seven patients (68.1%) had non-ischemic cardiomyopathy (NICM), 13 patients (18.9%) had ischemic-cardiomyopathy (ICM), and 9 patients (13%) had myocarditis. Standard percutaneous sub-xiphoid access was attempted in all patients. Non-inducibility of any VT was achieved in 82.6% (9/9 myocarditis, 10/13 ICM, 38/47 NICM, n = 57/69 patients), inducibility of non-clinical VT in 13% (3/13 ICM, 6/38 NICM, n = 9/69 patients), and failure in 4.3% (3/38 NICM, n = 3/69 patients). Although we observed procedural-related complications in five patients (7.2%), one transient PN palsy, two pericarditis, and two vascular complications, those were not related to the conscious sedation protocol. No respiratory failure, severe hypotension, or bradycardia requiring treatment has been observed among the patients. Prompt availability of anesthesiology support remains crucial for complex procedures such as epicardial VT ablation. Continuous infusion of dexmedetomidine and administration of midazolam and fentanyl seem to be a safe and effective sedation protocol in patients undergoing epicardial VT ablation.

Epicardial access facilitated by carbon dioxide insufflation via intentional coronary vein exit: step-by-step description of the technique and review of the literature.

Pericardial access from a subxiphoid approach is often necessary to gain access to a critical epicardial substrate that is inaccessible from the endocardium. Although relatively safe, a rate of up to 5% of acute and 2% delayed complications has been reported. Intentional perforation of a distal coronary vein branch with pericardial insufflation of CO2 to create a negative contrast space anterior to the right ventricle is an emerging approach to facilitate pericardial access. In this report, we describe the technique of intentional coronary vein exit with CO2 insufflation to perform epicardial mapping and ablation of ventricular tachycardia (VT) in a step-by-step approach and review the published literature on this topic.

Epicardial mapping as first intention approach for structural ventricular tachycardia ablation

Abstract Funding Acknowledgements Type of funding sources: None. Introduction In several structural arrhythmogenic diseases that comprise intricate endocardial, intramural and epicardial substrates, endocardial ablation of ventricular tachycardia (VT) is not sufficient and epicardial ablation has lately become a complementary and necessary tool. Purpose To evaluate the clinical characteristics of patients (pts) most suitable for first intention epicardial VT ablation. Methods Single-center prospective study of consecutive pts with structural heart disease undergoing first intention epicardial VT mapping between August 2015 and June 2021. Decision for epicardial approach was based on the etiology, VT electrocardiogram (ECG) and cardiac magnetic resonance (CMR) results. Under general anesthesia, subxiphoid access using a Tuhoy needle was done using fluoroscopic guidance and with high-density epicardial mapping was performed. Epicardial ablation was performed if relevant arrhythmogenic findings were locally confirmed. Results First intention epicardial VT ablation was attempted in 18 pts (mean age 59.8±12 years,94% male) of whom 16 had non-ischemic dilated cardiomyopathy (NICM,idiopathic:11; post-myocardis:4; hereditary:1) and 2 had right ventricular arrhythmogenic cardiomyopathy. Mean LVEF was 33% and 79% had a previous ICD (53% in primary prevenon). 69% were referred for ablation due to arrhythmic storm (1pt in cardiogenic shock). Epicardial access was achieved in 17 pts (94%), without acute complications. In 35% pts with NICM the decision for epicardial approach was based on the detection of subepicardial CMR delayed-hyperenhancement and relevant epicardial arrhythmic substrate was confirmed by mapping in all cases. In 3 pts radiofrequency (RF) applicaons were not performed at epicardium, as no abnormal electrograms were locally detected, and an addional endocardial approach was prosecuted. The mean overall procedure and fluoroscopic time were 123 and 28min, respectively, with a mean RF application me of 51min. After the procedure 1pt required pericardial drainage due to inflammatory pericardial effusion. No other acute complications occurred. During a mean follow-up of 2.8±1.8 years, only 3pts (17%) had VT recurrence; 5pts (28%) died due to end-stage heart failure and 2pts (11%) underwent heart transplantation. Conclusion In NICM a first intention epicardial VT ablation performed by experienced operators/centers is efficient, particularly if guided by CMR findings,and presents a safety profile.

Epicardial mapping and ablation of ventricular tachycardia from the coronary venous system in post-coronary bypass patients.

Ventricular tachycardia (VT) ablation of mid- or epicardial substrate is difficult and requires a creative approach in patients with a history of coronary bypass that precludes percutaneous epicardial catheter manipulation. The coronary venous system (CVS) provides limited access to the epicardial surface of the heart. The objective of this study is to assess the feasibility, safety, and efficacy of epicardial mapping and ablation of VT substrates from the CVS in patients with history of coronary bypass. Patients undergoing VT ablation at our institution were retrospectively reviewed. Those who had basal to mid ventricular substrate based on computed tomography imaging and history of coronary bypass were included. Endocardial and CVS mapping and ablation was performed in standard fashion using 3D electroanatomic mapping. The primary endpoint was defined as VT circuit elimination, termination, non-inducibility, or perturbation of the circuit. Of 192 consecutive VT ablations from 2017 to 2020, 35 (18%) had a history of coronary bypass and basal to the mid-ventricular substrate by imaging. There were no significant characteristic differences between the endocardial only (n = 19) vs endocardial + CVS (n = 16) groups. In 14 (88%) of patients undergoing CVS mapping, the VT circuit was identified to be within access from the epicardial surface. Ablation was attempted in 8 (57%) of these patients, and the primary endpoint was reached in 88% of those undergoing CVS ablation. There were no complications related to CVS ablation. Mapping and ablation of mid- or epicardial VT circuits from the CVS branches are feasible and safe and may be helpful in the treatment of VT in patients who are otherwise not candidates for percutaneous epicardial ablation.

Relevant anatomy of epicardial space for the electrophysiologists

The arrhythmogenic substrate in patients with Chagas cardiomyopathy, arrhythmogenic dysplasia, postmyocarditis nonischemic dilative cardiomyopathy as well as after extensive posterior or anterior wall myocardial infarction is predominantly located epicardially. This can necessitate epicardial access for an effective, substrate-based catheter ablation of the ventricular tachycardia (VT). Anterior percutaneous epicardial puncture represents the standard approach for epicardial VT ablation. The most important anatomical particularities that must be taken into account when performing an epicardial puncture or epicardial VT ablation are epicardial coronary arteries, left phrenic nerve and epicardial fat. The typical anatomic characteristics of the epicardial structures and resulting considerations for epicardial access are discussed here in detail.

PO-642-01 ESOPHAGO-PERICARDIAL FISTULA AS A RARE AND LIFE-THREATENING COMPLICATION OF EPICARDIAL VENTRICULAR TACHYCARDIA ABLATION

Esophago-pericardial fistula is a rare but potentially devastating complication of epicardial ventricular tachycardia ablation. This case highlights the importance of recognition of this potential risk, as well as timely treatment.