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Background: The hybrid convergent procedure is approved to treat symptomatic patients with long-standing persistent atrial fibrillation (AF). Despite direct visualization during surgical ablation as well as the use of luminal oesophageal temperature (LET) monitoring, oesophageal injury is still possible. A dedicated device for proactive oesophageal cooling has recently been cleared by the Food and Drug Administration to reduce the likelihood of ablation-related oesophageal injury resulting from radiofrequency cardiac ablation procedures. This report describes the first uses of proactive oesophageal cooling for oesophageal protection during the epicardial ablation portion of hybrid convergent procedures. Case summary: Five patients with long-standing persistent AF underwent hybrid convergent ablations with the use of proactive oesophageal cooling as means of oesophageal protection. All cases were completed successfully with no adverse effects. Most notably, cases were shorter when compared to cases using LET monitoring, likely due to lack of pauses for overheating of the oesophagus that would otherwise be required to prevent damage to the oesophagus. Discussion: This report describes the first uses of proactive oesophageal cooling for oesophageal protection during the epicardial ablation portion of five hybrid convergent procedures. Use of cooling enabled uninhibited deployment of lesions without the need to pause energy delivery due to elevated temperatures in the oesophagus, providing a feasible alternative to LET monitoring.
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INTRODUCTION: Patients with viral myocarditis can present with challenging life-threatening arrhythmias. Catheter ablation can be a life-saving procedure in some patients with recurrent drug-refractory ventricular arrhythmias. METHODS AND RESULTS: A patient with three prior ablations targeting two different monomorphic ventricular tachycardias (MMVTs) presented with recurrent ventricular tachycardia (VT). Consequently, he underwent epicardial mapping with adjuvant AI-enabled CT images with the creation of a three-dimensional model, which demonstrated a midmyocardial scar. Fractionated potentials were noted during mapping in this region, and entrainment suggested an inner loop. Interestingly, pacing showed two different QRS morphologies identical to his previously ablated VTs with a long stim-QRS at this region. Epicardial ablation carried on during the VT successfully terminated it, but the VT remained inducible and required endocardial ablation to make it noninducible. CONCLUSION: This case emphasizes the importance of recognizing possible three-dimensional VT circuits in some patients and the need to understand and target mid-myocardial substrate from both the endocardium and epicardium to achieve the elimination of the VT circuits.
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An epicardial approach is often used in radiofrequency (RF) catheter ablation to ablate ventricular tachycardia when an endocardial approach fails. Our objective was to analyze the effect of the position of the dispersive patch (DP) on lesion size using computer modeling during epicardial approach. We compared the posterior position (patient's back), commonly used in clinical practice, to the anterior position (patient's chest). The model considered ventricular wall thicknesses between 4 and 8 mm, and electrode insertion depths between .3 and .7 mm. RF pulses were simulated with 20 W of power for 30 s duration. Statistically significant differences (P < .001) were found between both DP positions in terms of baseline impedance, RF current (at 15 s) and thermal lesion size. The anterior position involved lower impedance (130.8 ± 4.7 vs. 146.2 ± 4.9 Ω) and a higher current (401.5 ± 5.6 vs. 377.5 ± 5.1 mA). The anterior position created lesion sizes larger than the posterior position: 8.9 ± 0.4 vs. 8.4 ± 0.4 mm in maximum width, 8.6 ± 0.4 vs. 8.1 ± 0.4 mm in surface width, and 4.5 ± 0.4 vs. 4.3 ± 0.4 mm in depth. Our results suggest that: (1) the redirection of the RF currents due to repositioning the PD has little impact on lesion size and only affects baseline impedance, and (2) the differences in lesion size are only 0.5 mm wider and 0.2 mm deeper for the anterior position, which does not seem to have a clinical impact in the context of VT ablation.
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Ablación por Catéter , Simulación por Computador , Electrodos , Ventrículos Cardíacos , Humanos , Ventrículos Cardíacos/cirugía , Ablación por Catéter/métodos , Ablación por Radiofrecuencia/métodos , Modelos Cardiovasculares , Pericardio/cirugía , Taquicardia Ventricular/cirugía , Taquicardia Ventricular/fisiopatologíaRESUMEN
Intraoperative ventricular tachycardia (VT) ablation targeting the epicardial substrate using three-dimensional electroanatomic mapping (EAM) was performed during left ventricular assist device (LVAD) implantation. We proved that EAM can be safely performed during LVAD implantation and that an ablation strategy based on electrophysiological information may reduce VT recurrence after LVAD implantation.
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BACKGROUND: Comparative efficacy and safety data on radiofrequency ablation (RFA) versus pulsed field ablation (PFA) for common idiopathic left ventricular arrhythmia (LV-VAs) locations are lacking. OBJECTIVES: This study sough to compare RFA with PFA of common idiopathic LV-VAs locations. METHODS: Ten swine were randomized to PFA or RFA of LV interventricular septum, papillary muscle, LV summit via distal coronary sinus, and LV epicardium via subxiphoid approach. Ablations were delivered using an investigational dual-energy (RFA/PFA) contact force (CF) and local impedance-sensing catheter. After 1-week survival, animals were euthanized for lesion assessment. RESULTS: A total of 55 PFA (4 applications/site of 2.0 KV, target CF ≥10 g) and 36 RFA (CF ≥10 g, 25-50 W targeting ≥50 Ω local impedance drop, 60-second duration) were performed. LV interventricular septum: average PFA depth 7.8 mm vs RFA 7.9 mm (P = 0.78) and no adverse events. Papillary muscle: average PFA depth 8.1 mm vs RFA 4.5 mm (P < 0.01). Left ventricular summit: average PFA depth 5.6 mm vs RFA 2.7 mm (P < 0.01). Steam-pop and/or ventricular fibrillation in 4 of 12 RFA vs 0 of 12 PFA (P < 0.01), no ST-segment changes observed. Epicardium: average PFA depth 6.4 mm vs RFA 3.3 mm (P < 0.01). Transient ST-segment elevations/depressions occurred in 4 of 5 swine in the PFA arm vs 0 of 5 in the RFA arm (P < 0.01). Angiography acutely and at 7 days showed normal coronaries in all cases. CONCLUSIONS: In this swine study, compared with RFA, PFA of common idiopathic LV-VAs locations produced deeper lesions with fewer steam pops. However, PFA was associated with higher rates of transient ST-segment elevations and depressions with direct epicardium ablation.
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BACKGROUND: The implantable cardioverter-defibrillator (ICD) prevents sudden cardiac death in patients with ischemic cardiomyopathy (ICM). Catheter ablation has been shown to effectively reduce ventricular tachycardia (VT) recurrence, yet its efficacy in patients without an ICD implantation remains uncertain. OBJECTIVE: We aimed to investigate the outcomes of ablation for VT in patients with ICM without a backup ICD. METHODS: Patients with ICM who received ablation for VT without an ICD implantation were included in this study. Ablation was guided by either activation mapping or substrate mapping. Endocardial ablation was the primary strategy; epicardial access was considered when endocardial ablation failed. The primary end point was VT recurrence during follow-up; secondary end points included cardiovascular rehospitalization, all-cause mortality, and a composite of these events. RESULTS: A total of 114 patients were included, with the mean age of 58.2 ± 11.1 years, 102 of whom (89.5%) were male. Twelve patients (10.5%) underwent endo-epicardial ablation, whereas the rest received endocardial ablation. With a median follow-up of 53.8 months (24.8-84.2 months), VT recurred in 45 patients (39.5%), and 6 patients (5.3%) died, including 2 sudden cardiac deaths. The recurrence rate of VT was significantly lower in patients undergoing endo-epicardial ablation than in those with endocardial ablation only (8.3% vs 43.1%; log-rank P = .032). After multivariate adjustment, epicardial ablation remained associated with a reduced risk of VT recurrence (hazard ratio, 0.14; 95% confidential interval, 0.02-0.98; P = .048). CONCLUSION: Patients with ICM undergoing VT ablation without a backup ICD experienced a notably low rate of arrhythmic death. Most recurrences proved nonlethal.
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OBJECTIVES: To investigate the predictive values of surface electrocardiogram-derived parameters in patients with atrial fibrillation who underwent thoracoscopic epicardial ablation. METHODS: The present study included 102 patients with atrial fibrillation who underwent thoracoscopic epicardial ablation and whose baseline 12-lead electrocardiograms were available. Frequency domain analysis was performed to calculate the electrocardiogram-derived parameters. Cox proportional hazards regression was used to identify predictive risk factors for postoperative recurrence. RESULTS: At 36-month interval, the overall rate of freedom from atrial tachyarrhythmia without antiarrhythmic drugs was 58.5%. The results of the univariable and multivariable analyses showed that larger left atrial diameter (hazard ratio: 1.074, 95% confidence interval: 1.021-1.130, P = 0.006) was an independent risk factor for atrial fibrillation recurrence, while higher fibrillatory wave amplitude was a protective factor (hazard ratio: 0.292, 95% confidence interval: 0.157-0.542, P < 0.001). The associations were clarified by the restricted cubic splines. The dominant frequency and organization index were not identified as statistically significant parameters. CONCLUSIONS: The fibrillatory wave amplitude has the highest predictive value for atrial fibrillation recurrence in electrocardiogram-derived parameters. Together with left atrial diameter, it may help identify patients in whom thoracoscopic ablation is likely to be effective.
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PURPOSE OF REVIEW: Percutaneous radiofrequency (RF) catheter ablation is an established strategy to prevent ventricular tachycardia (VT) recurrence and ICD shocks. Yet delivery of durable lesion sets by means of traditional unipolar radiofrequency ablation remains challenging, and left ventricular transmurality is rarely achieved. Failure to ablate and eliminate functionally relevant areas is particularly common in deep intramyocardial substrates, e.g. septal VT and cardiomyopathies. Here, we aim to give a practical-orientated overview of advanced and emerging RF ablation technologies to target these complex VT substrates. We summarize recent evidence in support of these technologies and share experiences from a tertiary VT centre to highlight important "hands-on" considerations for operators new to advanced RF ablation strategies. RECENT FINDINGS: A number of innovative and modified radiofrequency ablation approaches have been proposed to increase energy delivery to the myocardium and maximize RF lesion dimensions and depth. These include measures of impedance modulation, combinations of simultaneous unipolar ablations or true bipolar ablation, intramyocardial RF delivery via wires or extendable RF needles and investigational linear or spherical catheter designs. Recent new clinical evidence for the efficacy and safety of these investigational technologies and strategies merits a re-evaluation of their role and clinic application for percutaneous VT ablations. Complexity of substrates targeted with percutaneous VT ablation is increasing and requires detailed preprocedural imaging to characterize the substrate to inform the procedural approach and selection of ablation technology. Depending on local experience, options for additional and/or complementary interventional treatments should be considered upfront in challenging substrates to improve the success rates of index procedures. Advanced RF technologies available for clinical VT ablations include impedance modulation via hypotonic irrigation or additional dispersive patches and simultaneous unipolar as well as true bipolar ablation. Promising investigational RF technologies involve an extendable needle RF catheter, intramyocardial RF delivery over intentionally perforated wires as well as a variety of innovative ablation catheter designs including multipolar linear, spherical and partially insulated ablation catheters.
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Ablación por Catéter , Taquicardia Ventricular , Humanos , Taquicardia Ventricular/cirugía , Taquicardia Ventricular/fisiopatología , Ablación por Catéter/métodos , Ablación por Catéter/instrumentación , Diseño de EquipoRESUMEN
BACKGROUND: Pulsed Field Ablation (PFA) has recently been proposed as a non-thermal energy to treat atrial fibrillation by selective ablation of ganglionated plexi (GP) embedded in epicardial fat. While some of PFA-technologies use an endocardial approach, others use epicardial access with promising pre-clinical results. However, as each technology uses a different and sometimes proprietary pulse application protocol, the comparation between endocardial vs. epicardial approach is almost impossible in experimental terms. For this reason, our study, based on a computational model, allows a direct comparison of electric field distribution and thermal-side effects of both approaches under equal conditions in terms of electrode design, pulse protocol and anatomical characteristics of the tissues involved. METHODS: 2D computational models with axial symmetry were built for endocardial and epicardial approaches. Atrial (1.5-2.5 mm) and fat (1-5 mm) thicknesses were varied to simulate a representative sample of what happens during PFA ablation for different applied voltage values (1000, 1500 and 2000 V) and number of pulses (30 and 50). RESULTS: The epicardial approach was superior for capturing greater volumes of fat when the applied voltage was increased: 231 mm3/kV with the epicardial approach vs. 182 mm3/kV with the endocardial approach. In relation to collateral damage to the myocardium, the epicardial approach considerably spares the myocardium, unlike what happens with the endocardial approach. Although the epicardial approach caused much more thermal damage in the fat, there is not a significant difference between the approaches in terms of size of thermal damage in the myocardium. CONCLUSIONS: Our results suggest that epicardial PFA ablation of GPs is more effective than an endocardial approach. The proximity and directionality of the electric field deposited using an epicardial approach are key to ensuring that higher electric field strengths and increased temperatures are obtained within the epicardial fat, thus contributing to selective ablation of the GPs with minimal myocardial damage.
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Fibrilación Atrial , Simulación por Computador , Endocardio , Modelos Cardiovasculares , Pericardio , Endocardio/fisiopatología , Humanos , Fibrilación Atrial/fisiopatología , Fibrilación Atrial/cirugía , Ablación por Catéter/métodosRESUMEN
Left ventricular apical aneurysms are associated with scar-related ventricular tachycardia (VT) in hypertrophic cardiomyopathy patients. We present a patient with apical hypertrophic cardiomyopathy who underwent combined epicardial and endocardial VT ablation of a left ventricular apical aneurysm, necessitating repeat endocardial VT ablation through a recanalized surgical plication.
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BACKGROUND: Long-term success rates of catheter ablation (CA) for long-standing persistent atrial fibrillation (LSPAF) are less than satisfactory. Further improvement of ablation methods is crucial for enhancing the treatment of LSPAF. OBJECTIVES: This study sought to compare the outcomes of concurrent vs staged minimally invasive surgical-catheter hybrid ablation for LSPAF. METHODS: From December 2015 to December 2021, 104 matched patients (concurrent and staged, 1:1) were included in study. In the concurrent group, both left unilateral thoracoscopic epicardial ablation (EA) and CA were performed simultaneously in one procedure. In the staged group, EA was performed at the first hospitalization. If the patients experienced atrial fibrillation (AF) recurrence, CA was performed between 3 months and 1 year after EA. RESULTS: In the concurrent group, 4 patients were restored to sinus rhythm after EA, and 41 were patients restored to sinus rhythm during CA; 86.5% (45 of 52) achieved intraprocedural AF termination during concurrent hybrid ablation. In the staged group, all 52 patients underwent staged CA because of the recurrence of AF or atrial tachycardia (AT). Forty-seven (90.4%) patients achieved intraprocedural AF or AT termination during CA. Freedom from AF or AT off antiarrhythmic drugs at 2 years after hybrid ablation was 79.9% ± 5.7% in the concurrent group and 86.0% ± 4.9% in the staged group (P = 0.390). Failure of intraprocedural AF termination (HR: 14.378) was an independent risk factor for AF recurrence after hybrid ablation. CONCLUSIONS: Both concurrent and staged hybrid ablation could be safely and effectively applied to treat LSPAF. Improving the intraprocedural AF termination rate predicted better outcomes.
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Fibrilación Atrial , Ablación por Catéter , Puntaje de Propensión , Toracoscopía , Humanos , Fibrilación Atrial/cirugía , Ablación por Catéter/métodos , Femenino , Masculino , Persona de Mediana Edad , Anciano , Toracoscopía/métodos , Recurrencia , Resultado del Tratamiento , Estudios de Cohortes , Estudios RetrospectivosRESUMEN
A 15-year-old boy with manifest preexcitation and recurrent palpitations had undergone an unsuccessful ablation procedure elsewhere and was subsequently referred to us. The ECG suggested a left free wall pathway but there was a pattern break in lead V2. This helped localise the accessory pathway to the summit region and achieve success.
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BACKGROUND: The CONVERGE trial demonstrated that hybrid epicardial and endocardial ablation was more effective than catheter ablation for the treatment of persistent atrial fibrillation (AF) at 1 year. Long-term real-world outcome data are scarce. OBJECTIVE: We described a single-center experience by evaluating the long-term effectiveness and safety of hybrid epicardial-endocardial ablation. METHODS: This is a retrospective single-center study. Patients were followed up to 4 years. The primary end point was the rate of AF recurrence up to 4 years postablation. Secondary end points included reduction in antiarrhythmic therapy use, the effect of the ligament of Marshall removal, epicardial posterior wall, 3-dimensional mapping during epicardial ablation, and left atrial appendage exclusion as adjunct intraoperative interventions for AF recurrence. RESULTS: Of the 170 patients, 86.5% had persistent AF and 13.5% had long-standing persistent AF. AF-free survival was 87.6% at 1 year, 76.9% at 2 years, 70.4% at 3 years, and 59.3% at 4 years. Antiarrhythmic drug use was 87.6% at baseline and reduced to 21%, 20.6%, 18%, and 14.1% at year 1, 2, 3, and 4, respectively (P < .01 for all). Three-dimensional epicardial mapping showed a significant reduction in combined recurrence from 42% to 25% over 4 years of follow-up (P = .023). Ligament of Marshall and left atrial appendage exclusion showed numerical reduction in AF recurrence from 35% to 26% (P = .49) and from 44% to 30% (P = .07). CONCLUSION: The hybrid convergent procedure reduces AF recurrence and the need for antiarrhythmic drugs and, while maintaining a good safety profile, for the treatment of persistent and long-standing persistent AF.
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Background: Despite modern techniques for ablation of ventricular tachycardia (VT), the procedure faces challenges such as deep intramural substrates or inaccessibility of the pericardial space. We aim to present a case of successful surgical treatment of a patient with drug-refractory VT, an apical aneurysm, large left ventricular (LV) thrombus, and recurrent implantable cardioverter defibrillator (ICD) shocks following failed epicardial catheter ablation. Case summary: A 67-year-old male with a history of ischaemic cardiomyopathy was brought to the emergency room after a syncope because of VT. The VT was terminated by an external cardioversion prior to admission. The ICD interrogation showed an episode of sustained monomorphic VT with eight appropriate but mostly ineffective ICD shocks. An echocardiogram revealed an apical aneurysm with a thrombus. Anticoagulation and antiarrhythmic drug therapy were initiated. Days later, the patient suffered recurrent episodes of sustained VTs, refractory to pharmacological therapy, and epicardial ablation; therefore, following aneurysmectomy and thrombus removal, a reconstruction of the LV and surgical endocardial cryoablation were performed. In addition, ICD extraction was done due to recurrent bacteraemia with Staphylococcus aureus. A subcutaneous ICD was later implanted. After surgery, the patient remained free of any VT episodes during 44 months of follow-up. Conclusion: Combined surgical ventricular reconstruction and intraoperative cryoablation may be considered as an alternative, highly effective therapy in patients with drug-refractory VTs in the setting of a LV thrombus.
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BACKGROUND: Bipolar radiofrequency ablation (B-RFA) is a method used to treat the arrhythmia substrate resistant to unipolar ablation. Few studies have addressed endo-epicardial B-RFA. OBJECTIVE: The aim of the study was to evaluate chronic lesions resulting from endo-epicardial B-RFA and to determine optimal settings for such procedures in an animal model. METHODS: In 7 pigs, up to 5 radiofrequency applications per animal were performed with 2 electrodes placed on both sides of the left ventricular free wall. Current was delivered for 60 seconds by a generator dedicated for B-RFA with power settings of 25, 30, 35, 40, and 50 W. RESULTS: At 12 weeks after ablation, 31 lesions were assessed. Their maximal cross-sectional area ranged from 7.2 to 68 mm2 and correlated with total power delivered (r = 0.53), with temperature increment at the endocardial catheter (r = 0.65), and inversely with temperature decrement at the epicardial catheter (r = 0.54). For power values between 30 and 40 W, the lesion area did not differ significantly (P = .92). Lesion depth ranged from 1.9 to 11 mm and correlated with impedance decrement (r = 0.5). Lesions were transmural in 8 cases. Lesion depth/wall thickness ratio was on average 0.6 ± 0.3, with the smallest value for 25 W (0.5 ± 0.3) and the largest for 50 W (0.8 ± 0.3). Steam pops occurred at a power range of 30-50 W, with an incidence of 1 in 5 applications, with 1 case of fatal tamponade at 40 W. Impedance decrement, endocardial catheter temperature increment, and endocardial electrogram amplitude decrement were greater during applications with steam pops. CONCLUSION: Chronic lesions resulting from endo-epicardial B-RFA appear smaller and less often transmural compared with acute lesions described in the literature. The incidence of steam pops during endo-epicardial B-RFA is relatively high even at low powers.
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Ablación por Catéter , Modelos Animales de Enfermedad , Endocardio , Estudios de Factibilidad , Pericardio , Animales , Porcinos , Pericardio/cirugía , Endocardio/cirugía , Ablación por Catéter/métodos , Ventrículos Cardíacos/fisiopatología , Diseño de EquipoRESUMEN
BACKGROUND: 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. METHODS: 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 ± 23 months were reported. RESULTS: In total, 197 patients undergoing a total of 239 procedures were included (59.8 ± 15.3 years, 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). CONCLUSIONS: 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.