Epicardial Approach Research Articles

Percutaneous Epicardial Approach toCatheterAblation of CardiacArrhythmias.

Since their introduction >2 decades ago, percutaneous catheter-based epicardial mapping and ablation have become widely adopted by cardiac electrophysiologists around the world. Although epicardial mapping has been used for catheter ablation of a wide variety of cardiac arrhythmias, its most common use is for ablation of intramural and subepicardial substrates that give rise to ventricular tachycardia, particularly in patients with nonischemic cardiomyopathy. As such, the subxiphoid percutaneous epicardial approach has emerged as an important adjunct, and, in some cases, is the preferred strategy in this regard. This review discusses the rationale and indications for epicardial catheter mapping and/or ablation. This paper also reviews the prevalence of epicardial arrhythmias and their electrocardiographic criteria. In addition, it examines the anatomy of the pericardium and commonly used epicardial access techniques, as well as the optimal methodologies for epicardial mapping and ablation and the impact of epicardial fat. Finally, this review discusses the potential of the various complications associated with the percutaneous epicardial approach, in addition to patient-specific risk factors, and potential strategies to mitigate the risk of complications.

Epicardial approach for cardiac electrophysiology procedures.

Since its introduction over two decades ago, percutaneous epicardial procedures have become well-adopted by cardiac electrophysiologists, most commonly for catheter ablation of cardiac arrhythmias as well as left atrial appendage closure. The percutaneous epicardial approach has also been utilized for cardiac pacing and drug delivery. But still, its most common usage is for the treatment of intramural and subepicardial substrates that give rise to ventricular tachycardia, particularly in patients with nonischemic cardiomyopathy. In fact, subxiphoid, percutaneous epicardial mapping and ablation have emerged as an important adjunct and in some cases the preferred strategy for characterizing and treating certain types of ventricular arrhythmias. Herein, we will review the indications and rationale for various epicardial procedures. Additionally, we will explore the anatomy of the pericardium as well as the frequently-used epicardial access techniques. We will further examine the optimal approaches and methodologies for epicardial mapping and ablation and the impact of epicardial fat. We will also discuss the epicardial technique for left atrial appendage closure for the purpose of embolic stroke risk reduction. Finally, we will consider the potential for various complications in the setting of epicardial procedures along with their risk factors and discuss strategies to mitigate such adverse events.

Application of noninvasive signal-averaged electrocardiogram analysis in predicting the requirement of epicardial ablation in patients with arrhythmogenic right ventricular cardiomyopathy

Signal-averaged electrocardiogram (SAECG) provides not only diagnostic information but also the prognostic implication of ablation in arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aimed to validate the role of SAECG in identifying arrhythmogenic substrates requiring an epicardial approach in ARVC. Ninety-one patients with a definite diagnosis of ARVC who underwent successful ablation for drug-refractory ventricular arrhythmia were enrolled and classified into 2 groups: group 1 who underwent successful ablation at the endocardium only and group 2 who underwent successful ablation requiring an additional epicardial approach. The baseline characteristics of patients and SAECG parameters were obtained for analysis. Male predominance, worse right ventricular (RV) function, higher incidence of syncope, and depolarization abnormality were observed in group 2. Moreover, the number of abnormal SAECG criteria was higher in group 2 than in group 1. After a multivariate analysis, the independent predictors of the requirement of epicardial ablation included the number of abnormal SAECG criteria (odds ratio 2.8, 95% confidence interval 1.4-5.4; P = .003) and presence of syncope (odds ratio 11.7; 95% confidence interval 2.7-50.4; P = .001). In addition, ≥2 abnormal SAECG criteria were associated with larger RV endocardial unipolar low-voltage zone (P < .001), larger RV endocardial/epicardial bipolar low-voltage zone/scar (P < .05), and longer RV endocardial/epicardial total activation time (P < .001 and P = .004, respectively). The number of abnormal SAECG criteria was correlated with the extent of diseased epicardial substrates and could be a potential surrogate marker for predicting the requirement of epicardial ablation in patients with ARVC.

Patient Selection for Epicardial Ablation-Part II: The Epicardial Approach and Current Challenges Associated with Epicardial Ablation.

Since their inception, percutaneous epicardial approaches have become increasingly common in clinical practice with the advent of new technology and the growth of catheter ablation for both ventricular and supraventricular arrhythmias. In addition to identifying the arrhythmogenic foci, there remain challenges to successful epicardial ablation such as the choice of energy source, optimizing irrigation during ablation, and anatomic barriers such as epicardial fat and coronary vessels. The performance of continued translational studies to understand how each of these factors contribute to lesion formation will be essential to guide future advances in the field of epicardial ablation.

Patient Selection for Epicardial Ablation-Part I: The Role of Epicardial Ablation in Various Cardiac Disease States.

Epicardial catheter ablation is most commonly performed following unsuccessful endocardial ablation. Given the frequency of epicardial substrates in certain cardiomyopathic disease states, however, a combined endocardial–epicardial approach should be considered as a primary treatment strategy. Although epicardial ablation is primarily deployed in patients with ventricular arrhythmias, the role of epicardial approaches in supraventricular tachycardias (eg, atrial fibrillation, inappropriate sinus tachycardia, and—rarely—accessory pathways) is growing, with continued advances being made.

P5693Critical sites for scar-related ventricular tachycardias treatment: an approach based on sinus rhythm late activation zones

Abstract Introduction Despite advances in antiarrhythmic and device therapy, ventricular tachycardia (VT) is a major cause of increased morbidity and mortality. During scar-mediated monomorphic VT ablation, the search for critical isthmus sites continues to be the primary goal during successful ablative procedures. However, catheter ablation based on conventional mapping techniques is associated with low success rates and is limited to patients with stable VT. Objective The aim of the study was to evaluate, in patients with history of VT, the success of a strategy based on substrate mapping and ablation during sinus rhythm. Methods Retrospective single center analysis of patients undergoing VT ablation from November 2015 to November 2017. Clinical profiles and procedural details were determined. We used high-density structural map to identify voltage abnormalities as well a functional map of sinus rhythm activation to identify the regions of late potentials. Radiofrequency applications were performed in the areas with the latest activation. Recurrence of VT was considered the end-points of the follow-up. Results A total of 22 patients were included in the analysis, 95% male, with an median age of 65,5 (57–71) years old. The majority of the patients (18) with ischemic cardiomyopathy, 3 with nonischemic cardiomyopathy, and 1 with arrhythmogenic right ventricular cardiomyopathy were included. Epicardial mapping was performed in 27% of the cases. CARTO mapping system was used in 10 patients and Rhythmia in the remaining cases. Areas with the latest activation corresponded to regions of abnormal voltage in 21 patients. During a 26,5 (21,5–29,3) months of follow-up, the observed VT recurrence rate was 35%. 25% of the patients needed hospital admission due to arrhythmias and one patient died due to an arrhythmic cause. Treatment success was higher in epicardial approach (100% VS 50%, p=0,03). The location of the scar in the left ventricle was not a determinant of success (anterior-66,7% VS lateral/inferior-61,5%, p=0,806). Conclusion A substrate-based approach that targets regions of late activation within the scar seems attractive and may be a simple way to perform VT ablation with success. In our population, this strategy seams successful, especially in epicardial approach. Substrate modification strategies aiming to eradicate all potential reentrant circuits may be the most successful way to treat VT and avoid recurrences.

5201Intra-cardiac thrombus in patients undergoing ventricular tachycardia ablation. a computed tomographic scan study

Abstract Background Embolic event is one of the complications of VT ablation. This may be due to the presence of intra-cardiac thrombus before ablation. However, there is no clear consensus on how to rule out thrombus before the procedure. Objective We sought to examine the prevalence and risk factors of intra-cardiac thrombus with cardiac computed tomographic (CT) scan in patients undergoing scar-related VT ablation. Methods In absence of contra-indication, all patients undergoing scar-related VT ablation at our institution underwent contrast-enhanced cardiac CT within one week before ablation. 324 consecutive patients (292 male, 59±16 yo) have been included in this study. The etiology was ischemic cardiomyopathy (CMP) (n=191), arrhythmogenic right ventricular CMP (ARVC) (n=37), congenital CMP (n=11) or other CMP (n=85). LVEF was &lt;40% in 154 patients (48%). Results Intra-cardiac thrombus was diagnosed in 29 (9%) patients: in the left atrium (n=8), in the right atrium (n=1), in the left ventricle (n=15), in the right ventricle (n=3), in right and left atrium (n=1), and in left atrium and right ventricle (n=1). Moreover in 2, a bilateral pulmonary embolism was identified. The population with thrombus was older (65±12 vs 58±16 years, p=0,005), with more permanent atrial fibrillation (AF) (28% vs 8%; p=0.005). Patients with left ventricular (LV) aneurysm were at higher risk of thrombus 50% vs 3% (p&lt;0.001). The average CHADSVASC score was similar for both groups (2,5 vs 2,1; p=0.179). After matching for age and sex, only ischemic CMP and LV aneurysm were risk factors for thrombus. Because of arrhythmic storm, ablation was performed by epicardial approach only, in 5 patients with intra-ventricular thrombus and by retroaortic approach only, in 2 patients with LAA thrombus. No embolic event occurred during these procedures. Conclusion CT scans help eliminating intra-cardiac thrombus before VT ablation procedure. A high proportion of thrombus (9%) was identified. Whereas LV thrombus should systematically be ruled out before scar related VT ablation, in patients with AF, a LAA thrombus should also be eliminated as well as RV thrombus in patients with ARVC. Acknowledgement/Funding ANR-10-IAHU-04

P5694Outcomes of patients with arrhythmogenic right ventricular cardiomyopathy after ventricular tachycardia ablation without an implantable cardioverter-defibrillator: a multicenter international study

Abstract Background In arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D), implantable cardioverter-defibrillators (ICD) after an episode of sustained monomorphic ventricular tachycardia (MVT) are currently recommended in most situations. However, radiofrequency catheter ablation (RCA) is effective in reducing recurrent VT and whether MVT is a surrogate of sudden cardiac death is debated when other risk factors are lacking. Purpose To report the outcomes of patients with ARVC/D who underwent RCA of well-tolerated MVT without a back-up ICD. Methods Patients with a definite ARVC/D diagnosis according to the 2010 Task Force revised criteria who underwent RCA of well-tolerated MVT at 9 tertiary centers across 5 countries, without an ICD prior to RCA and in the 3 following months were retrospectively included. Patients presenting with syncope or electrical storm, and patients with left ventricular ejection fraction &lt;50% were excluded. Similar patients implanted with an ICD prior or without RCA in the same period served as controls. Results Sixty-five patients [median age 46.1 years, range (19.5–73.8), 75% males] underwent RCA of MVT between 2003 and 2016. Familial history of ARVC/D was found in 11% of patients. Epsilon-waves were present in 19% and T-waves inversion beyond V2 in 43%. A right ventricular (RV) ejection fraction ≤40% or fractional area change ≤33% was found in 14 (25%) patients. Median left ventricular ejection fraction was 61% (50–70). Clinical presentation was palpitations in 81% of patients and near-syncope in 14%. Prior to RCA, patients were on beta-blockers alone in 18%, class I drugs in 37% and amiodarone in 9%, while 15% of patients were free any antiarrhythmic medication. Only 1 patient (2%) had &gt;1 clinical VT morphology. Median VT rate was 180 (110–270). An epicardial approach was used in 31% patients. The clinical VT was inducible in 84% of patients. The median number of targeted RV site was 1 (1–3) (RV outflow tract in 72%). Full acute success defined inability to induce any VT was achieved in 72% of patients. During a median follow-up time of 49 month (1.4–162), there was no death or aborted cardiac arrest. Survival without VT recurrence was estimated at 82%, 71% and 60%, 12-, 36- and 60-months after RCA. No VT recurrence was observed among patient who had undergone an epicardial ablation. Among patients with VT recurrence, 6 (35%) did not receive an ICD, and 14 (70%) underwent redo RCA. An ICD was implanted in 10 patients, including 5 for VT recurrence. Fifty-eight patients constituted the control group, and 64% had appropriate ICD interventions during follow-up. Conclusions Despite a significant rate of VT recurrence, selected patients with ARVC/D who underwent RCA for stable MVT without an ICD did not experience any arrhythmic death. Further prospective studies are mandatory to precise the respective places of ICD and RCA in the management of ARVC/D patients with well-tolerated MVT. Acknowledgement/Funding None

Concomitant Cardiac Surgery and Radiofrequency Ablation of Atrial Fibrillation: A Retrospective Single Center Study

Concomitant cardiac surgery and radiofrequency atrial fibrillation (AF) ablation is an established procedure recommended in guidelines. However, the results have not been as good as expected. The authors therefore searched for predictive factors of success of the ablation procedure. The authors carried out a retrospective cohort study. All the included patients had cardiac surgery in the Dijon University Hospital. One hundred sixty-three patients with AF underwent a concomitant radiofrequency ablation between January 2009 and December 2016. A radiofrequency device was used to isolate the pulmonary veins creating a "Box lesion." The primary endpoint of the study was freedom from AF at 12 months with follow-up assessed by an electrocardiogram or a 24-hour recording electrocardiogram Holter. The patient's mean age was 71 ± 9 years with a sex ratio of 1.4. Sixty-six percent of patients had paroxysmal AF and 34% nonparoxysmal AF, which includes persistent and long-standing persistent AF. Sixty-one percent of patients had an AF history for more than 1 year. The mean left atrial diameter was 47 ± 10 mm. No major ablation complications related to the procedure occurred. Overall freedom from AF rate after 1-year follow-up was 60% (n = 98). Six patients (4%) received an additional catheter-based ablation, and 10 patients (6%) had an electrical cardioversion during the follow-up period. The authors identified preoperative paroxysmal AF (odds ratio [OR] 2.54 [1.27-5.14] p = 0.008) and recent history of AF, less than 1 year, (OR 1.99 [1-4.06] p = 0.05) as statistically significant predictors for sinus rhythm maintenance at the 12-month follow-up. At the 12-month follow-up, 64% of patients who had concomitant epicardial treatment were in sinus rhythm and 57% of patients were in sinus rhythm after endocardial treatment. There were no significant differences in rhythm outcome between epicardial and endocardial radiofrequency approach, or between surgical procedures (mitral valve replacement versus coronary artery bypass grafting). The authors could not identify in a univariate analysis a significant left atrium size cutoff upon which ablation was less likely to be successful at 12 months follow-up. Concomitant cardiac surgery and radiofrequency AF ablation provided freedom from AF for 60% of patients after 1-year follow-up. The authors have shown that paroxysmal AF and recent AF are predictive factors of success. Nevertheless, thorough postoperative care is necessary to improve long-term results, including the use of additional catheter ablation or cardioversion.

Left Atrial Occlusion Device Implantation: the Role of the Echocardiographer.

Atrial fibrillation is the most common arrhythmia worldwide and is a major risk factor for embolic stroke. For patients with atrial fibrillation who are unable to tolerate systemic anticoagulation, left atrial appendage (LAA) occlusion has been shown to mitigate stroke risk. In this article, we describe the vital role of the echocardiographer in intraprocedural guidance of percutaneous LAA occlusion procedures as well as in the pre- and post-procedure assessment of these patients. A few percutaneously delivered devices for LAA exclusion from the systemic circulation are available in contemporary practice. These devices employ an either exclusive endocardial LAA occlusion approach, such as the Watchman (Boston Scientific, Maple Grove, MN) and Amulet (St. Jude Medical, Minneapolis, MN), or both an endocardial and pericardial (epicardial) approach such as the Lariat procedure (SentreHEART, Palo Alto, CA). Two- and three-dimension transesophageal echocardiography is critical for patient selection, procedure planning, procedural guidance, and ensuring satisfactory immediate as well as long-term LAA occlusion/exclusion efficacy. This review will provide an overview of the role of the echocardiographer in all aspects of LAA occlusion/exclusion procedures for the most commonly used commercially available devices in current practice.

Ischemic ventricular tachycardia from below the posteromedial papillary muscle, a particular entity: Substrate characterization and challenges for catheter ablation

In patients with ischemic ventricular tachycardia (VT), substrate may be "protected" by the posteromedial papillary muscle (PMPM), explaining failure of endocardial-only ablation. We sought to characterize the arrhythmogenic substrate and ablation approach in patients with ischemic VT mapped to the inferior left ventricle in which endocardial ablation failed because of inaccessible substrate underlying the PMPM. We included 10 patients with recurrent ischemic VT, evidence of inferior scar, and failed endocardial ablation. In all patients, epicardial mapping was performed via a percutaneous (n = 9) or surgical (n = 1) approach, and VT elimination was achieved by ablation opposite to the PMPM. Clinical characteristics, electrocardiographic characteristics, and procedural data were analyzed. In all patients, intracardiac echocardiography showed hyperechoic scar below the PMPM, and 5 exhibited a pattern characterized by subendocardial basal scar that became intramural and epicardial at distal segments. In 4 patients, VT remained inducible despite endocardial scar isolation, manifested by the absence of electrograms, dissociated potentials, and/or exit block. Eleven inducible VTs were mapped to the epicardium underlying the PMPM: 8 had a right bundle branch block configuration with variable transition, while 3 exhibited left bundle branch block with negative concordance. An inferior QS pattern was present in 10 of 11 VTs. Noninducibility was achieved in 8 patients, and 7 patients remained arrhythmia-free after a mean follow-up of 27 ± 23 months. In patients with inferior ischemic scar, VT may arise from the area underneath the PMPM, limiting endocardial ablation. Intracardiac echocardiography accurately defines the substrate distribution, and an epicardial approach may eliminate VT. A pattern of "basal-endocardial/apical-epicardial" ischemic involvement is described.

Infusion Needle Radiofrequency Ablation for Treatment of Refractory Ventricular Arrhythmias

BackgroundCatheter ablation is effective for eliminating most drug-refractory ventricular arrhythmias (VA). However, a major reason for procedural failure is arrhythmia originating deep within the myocardium where it is inaccessible to conventional endocardial or epicardial approaches. Affected patients have limited therapeutic options. ObjectivesThe objective of this study was to assess the safety and outcome of a novel radiofrequency ablation catheter that used an extendable/retractable 27-g needle capable of targeting deep arrhythmia (intramural) substrate. MethodsPatients who failed at least one prior catheter ablation procedure for sustained ventricular tachycardia (VT) or nonsustained VA with associated left ventricular dysfunction were enrolled at 3 centers. The target was sustained monomorphic VT in 26 patients, including 8 with recent VT storm or VT requiring intravenous medication, and 5 with incessant VA associated with ventricular dysfunction. ResultsNeedle ablation was performed in 31 patients (median of 2 failed prior ablation procedures; 71% nonischemic heart disease). After a median of 15 needle lesions/patient, ablation abolished at least 1 inducible VT in 19 of 26 VT patients (73%), and suppressed ambient arrhythmia in 4 of 5 nonsustained arrhythmia patients. At the 6-month follow-up, 48% of patients were free of recurrent arrhythmia and another 19% were improved. Procedure-related complications included a single pericardial effusion treated with percutaneous drainage and a left ventricular pacing lead dislodgement with no deaths. ConclusionsIn patients with recurrent ventricular arrhythmias refractory to medications and conventional catheter ablation, intramural needle radiofrequency ablation offers significant arrhythmia control with an acceptable procedural risk.

Catheter Ablation of Ventricular Tachycardia in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia: A Sequential Approach.

BackgroundIt has been suggested that endocardial and epicardial ablation of ventricular tachycardia (VT) improves outcome in arrhythmogenic right ventricular cardiomyopathy/dysplasia. We investigated our sequential approach for VT ablation in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia in a single center.Methods and ResultsWe included 47 patients (44±16 years) with definite (81%) or borderline (19%) arrhythmogenic right ventricular cardiomyopathy/dysplasia between 1998 and 2016. Our ablation strategy was to target the endocardial substrate. Epicardial ablation was performed in case of acute ablation failure or lack of an endocardial substrate. Single and multiple procedural 1‐ and 5‐year outcome data for the first occurrence of the study end points (sustained VT/ventricular fibrillation, heart transplant, and death after the index procedure, and sustained VT/ventricular fibrillation for multiple procedures) are reported. Eighty‐one radiofrequency ablation procedures were performed (mean 1.7 per patient, range 1–4). Forty‐five (56%) ablation procedures were performed via an endocardial, 11 (13%) via an epicardial, and 25 (31%) via a combined endo‐ and epicardial approach. Complete acute success was achieved in 65 (80%) procedures, and partial success in 13 (16%). After a median follow‐up of 50.8 (interquartile range, [18.6; 99.2]) months after the index procedure, 17 (36%) patients were free from the primary end point. After multiple procedures, freedom from sustained VT/ventricular fibrillation was 63% (95% CI, 52–75) at 1 year, and 45% (95% CI, 34–61) at 5 years, with 36% of patients receiving only endocardial radiofrequency ablation. A trend (log rank P=0.058) towards an improved outcome using a combined endo‐/epicardial approach was observed after multiple procedures.ConclusionEndocardial ablation can be effective in a considerable number of arrhythmogenic right ventricular cardiomyopathy/dysplasia patients with VT, potentially obviating the need for an epicardial approach.

Feasibility of percutaneous epicardial mapping and ablation for refractory atrial fibrillation: Insights into substrate and lesion transmurality

Recurrences of atrial fibrillation (AF) after ablation have been attributed to conduction gaps and nontransmural ablation lesions. The purpose of this study was to assess the feasibility of adjunctive percutaneous mapping of the epicardial regions of the left atrium to characterize the transmural extent of substrate and ablation lesions. Between 2014 and 2018, combined epicardial and endocardial mapping of AF was performed in 18 patients via an inferior subxiphoid percutaneous approach (16 with previously failed ablation procedures and 2 patients with long-standing persistent AF) at 2 centers. Epicardial substrate mapping was compared with endocardial mapping to assess transmural uniformity. Of 18 patients, 4 (22%) demonstrated nontransmural atrial low-voltage regions with relative epicardial sparing in the left atrial posterior wall. Transmural isolation of the posterior wall was achieved after an endocardial "box" lesion set in 6/9 (67%), guided by epicardial voltage data, while epicardial and endocardial dissociation during AF was observed in 1 patient. In 3 patients, epicardial capture along the endocardial pulmonary vein lesion set despite endocardial capture loss and bidirectional block was observed. Two cases of mitral flutter were terminated from the epicardium. A balloon was positioned in the pericardial space in 6 patients for esophageal protection during ablation. A percutaneous epicardial approach for mapping and ablation of the left atrium is feasible in the electrophysiology laboratory during endocardial catheter ablation for AF and may be useful as an adjunctive approach in refractory cases. High-density epicardial mapping can provide direct evidence of nonuniform lesion and substrate transmurality of the human left atrium before and after ablation.

Electroporation of epicardial autonomic ganglia: Safety and efficacy in medium-term canine models.

Endocardial radiofrequency ablation of epicardial ganglionic plexus (GP) for atrial fibrillation (AF) is complicated by myocardial damage. We hypothesized that an epicardial approach with a novel nitinol catheter system capable of causing irreversible electroporation (IRE) with direct current (DC) could selectively and permanently destroy GP without collateral myocardial injury. Acute studies and medium-term terminal studies (mean survival, 1137 days) were performed with seven dogs. In the acute studies, DC was used to target epicardial GP within the transverse sinus, oblique sinus, vein of Marshall, and right periaortic space. Successful electroporation was defined as the presence of ablative lesions in the GP without collateral myocardial damage. A four-point integer system was used to classify histologic changes in tissue harvested from the ablation sites. Atrial effective refractory period (AERP) was measured during the acute and medium-term studies. For six dogs in the medium-term studies, the postablation period was uneventful without complications. Lesions were successfully created at 20 of 21 sites (95.2%) with more than minimal myocardial damage in one dog. An increase in AERP occurred in both atria during the acute studies but was maintained only in the right atrium at medium-term follow-up (5032 milliseconds). No dog had damage to the esophagus, adjacent great arteries, or pulmonary veins. This proof-of-concept study suggests that safe, effective, and selective epicardial ablation of GP can be performed with DC by IRE with minimal collateral myocardial damage.

Development of a Shock-Wave Catheter Ablation System for Ventricular Tachyarrhythmias: Validation Study in Pigs In Vivo.

BackgroundAlthough radiofrequency catheter ablation is the current state‐of‐the‐art treatment for ventricular tachyarrhythmias, it has limited success for several reasons, including insufficient lesion depth, prolonged inflammation with subsequent recurrence, and thromboembolisms due to myoendocardial thermal injury. Because shock waves can be applied to deep lesions without heat, we have been developing a shock‐wave catheter ablation (SWCA) system to overcome these fundamental limitations of radiofrequency catheter ablation. In this study, we evaluated the efficacy and safety of our SWCA system for clinical application to treat ventricular tachyarrhythmia.Methods and ResultsIn 33 pigs, we examined SWCA in vivo for the following 4 protocols. First, in an epicardial substrate model (n=8), endocardial SWCA significantly decreased the sensing threshold (pre‐ versus postablation: 11.4±3.8 versus 6.8±3.6 mV; P<0.05) and increased the pacing threshold (pre‐ versus postablation: 1.6±0.8 versus 2.0±1.1 V; P<0.05), whereas endocardial radiofrequency catheter ablation failed to do so. Second, in a myocardial infarction model (n=3), epicardial SWCA of the border zone of the infarcted lesion was as effective as ablation of the normal myocardium. Third, in a coronary artery application model (n=10), direct application of shock waves to the epicardial coronary arteries caused no adverse effects in either the acute or chronic phase. Fourth, with an epicardial approach (n=8), we found that 90 shots per site provided an ideal therapeutic condition to create deep lesions with less superficial damage.ConclusionsThese results indicate that our new SWCA system is effective and safe for treatment of ventricular tachyarrhythmias with deep arrhythmogenic substrates.

Percutaneous epicardial approach for ventricular tachycardia ablation in patients with structural heart disease – case series presentation form University Hospital Centre Split

Epikardna VT ablacija je vrlo invazivna procedura, no kada se radi u centrima s kardiokirurskom podrskom i velikim volumenom ablacijskih procedura, nudi mogucnost sigurnog izvođenja i daje sansu ostvariti kontrolu nad aritmijama koje ugrožavaju ne samo kvalitetu, vec i život ovih pacijenata.

Critical Role of the Posterior Left Atrium in the Perpetuation of Persistent Atrial Fibrillation and the Hybrid Ablation Approach for Persistent Atrial Fibrillation Management: A Single-center Outcomes Study.

Atrial fibrillation (AF) is the most common heart rhythm disorder and a growing major public health burden. AF ablation is considered to be the preferred rhythm control strategy for symptomatic drug-refractory paroxysmal and persistent AF (PRAF). To date, the long-term ablation success rates of pulmonary vein isolation (PVI) for PRAF and longstanding PRAF (LS-PRAF) have not paralleled those of paroxysmal AF. Additional concomitant ablation strategies such as linear ablation lesions in the left and right atria; autonomic ganglionic plexi ablation; ablation directed by complex fractionated atrial electrograms; ablation of nonpulmonary vein (PV) triggers; radiofrequency ablation of the vein of Marshall; and, most recently, focal impulse and rotor ablation/modulation have shown modest improvement in terms of efficacy, but no reproducible outcomes. Here, we describe the critical role of the posterior left atrium (LA) and PV region in the development and progression of PRAF and LS-PRAF. We discuss the results of single-center outcomes data for convergent or hybrid AF ablation of the posterior LA and PV region (endocardial PVI + minimally invasive epicardial posterior LA ablation). This epicardial ablation approach, combined with endocardial ablation, is an option for patients with PRAF and LS-PRAF. More definitive clinical trials are needed.

Idiopathic premature ventricular contractions originating from left ventricular summit successfully ablated from the epicardial approach

Catheter ablation of ventricular arrhythmias originating from the left ventricular summit can be challenging, given the high risk of vascular injury and low success rates during radiofrequency ablation. In case of failed endocardial ablation attempt, ablation from adjacent structures such as the coronary cusps, coronary venous system, and the septal right ventricular outflow tract should be tried as effective alternative approaches, respectively. Epicardial approach is an effective alternative strategy in failed cases. We report on a 45-year-old man with VAs originated from the LVS who underwent an epicardial ablation.

First Simultaneous Endocardial and Epicardial Mapping of a Ventricular Tachycardia in an ARVD/C Patient

A 73-year-old patient with an arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) was referred for ventricular tachycardia (VT) ablation. The procedure was performed with a combined endocardial and percutaneous epicardial approach, using the CARTO3 mapping system. After the clinical