Feasibility of Transatrial Access for Epicardial Ablation: Evaluation of 2 Different Techniques in Swine.

BACKGROUND: The subxiphoid pericardial access is technically difficult and has a considerable rate of complications, thus transatrial access may be an alternative. OBJECTIVES: This study sought to assess the feasibility and safety of this strategy regarding periprocedural period and after 1-week follow-up. METHODS: The investigators performed epicardial mapping through transatrial puncture in 20 swine. Animals were divided into group A, in which aspiration of the sheath was performed to maintain negative pressure after the withdraw of the catheters, and group B, in which a device (Konar-MF VSD Occluder) was delivered to occlude the right atrial appendage perforation. Bleeding was investigated immediately and 1 week after. RESULTS: Access was safe in 19 of 20 animals (95%) with small amount of bleeding (6.4 ± 6 mL). In group A (n = 10), 1 animal presented hemopericardium right after the puncture. In the other 9, epicardial ablation was performed and 60.0 ± 28.0 mL of blood was aspirated without events. After 1 week, fibrin-hemorrhagic pericarditis was identified in 3 animals. In group B (n = 10), reaching the epicardial surface was possible in all animals. An adequate position of the prosthesis was obtained in 90% (9 of 10). One death occurred in the immediate postoperative period, secondary to pneumothorax. After 1 week, postmortem analysis showed absence of pericardial bleeding and a normal-appearing pericardium in the 8 animals with adequate prosthesis position. CONCLUSIONS: Transatrial access allows epicardial mapping and ablation. Sheath removal after negative pressure contributes to achieving acute bleeding control but does not prevent its occurrence. The use of the device prevents bleeding and hemorrhagic pericarditis.

Catheter ablation of the parahisian accessory pathways from the aortic cusps-Experience of 20 cases-Improving the mapping strategy for better results.

INTRODUCTION: Catheter ablation of the parahisian accessory pathways (PHAP) has been established as the definitive therapy for this type of arrhythmia. However, the PHAP proximity to the normal atrioventricular conduction system makes the procedure technically challenging. Here, we have reported a case series of 20 patients with PHAP who underwent aortic access ablation to evaluate the safety and efficacy of this approach in the PHAP ablation. METHODS AND RESULTS: The ablation through the aortic cusps was the successful approach in 13 of 20 (65%) of the cases. In 11 patients, the aortic approach was the initial strategy for ablation, and the accessory pathway was eliminated in seven (63.6%) of them. The aortic approach followed a failed right-sided attempt in nine patients. In six (66.7%) patients, the ablation was successful with the aortic approach. The only independent predictor for the successful ablation with each approach was the earliest ventricular activation before delta wave (predelta time) and a right-sided earliest ventricular activation of more than 23 ms had high sensitivity and specificity for right-sided success. Systematically using the two strategies (right and left approaches), the ablation of the PHAP was successful in 18 (90%) patients. CONCLUSION: The aortic approach seems to be a safe and effective strategy for the ablation of PHAP. It can be used when the right-sided approach fails or even considered as an initial strategy when the predelta time is less than 23 ms in the right septal region. When combining the right- and left-sided approaches, the success rate is high. We believe that the retrograde aortic approach remains a key tool for this challenging ablation.

Comparative study of strategies to prevent esophageal and periesophageal injury during atrial fibrillation ablation.

OBJECTIVE: To compare the prevalence of esophageal and periesophageal thermal injury in patients undergoing radiofrequency (RF) atrial fibrillation (AF) ablation using 8 mm tip catheters during three different esophageal protection strategies. METHODS: Forty-five consecutive patients with paroxysmal or persistent AF underwent first ablation procedure, besides esophagogastroduodenoscopy (EGD) combined with radial endosonography (EUS) performed before and after the pulmonary vein (PV) isolation. Before the procedure, patients were randomly assigned to one of three esophageal lesion protection strategies: group I-without any protective or monitoring dispositive and limiting RF applications to 30 W for 20 seconds, in left atrium posterior wall (LAPW); group II-power and time of RF delivery, up to 50 W for 20 seconds at LAPW, limited by esophageal temperature monitoring; group III-applications of RF in LAPW with fixed power application of 50 W for 20 seconds during continuous esophageal cooling. RESULTS: Baseline characteristics of patients were similar in all groups. The four PVs were isolated in 14 (93.3%), 13 (86.7%), and 15 (100%) patients, respectively in groups I, II, and III. The mean RF power was significantly higher (P < .001) in the posterior side of PVs in group III. Post-AF ablation EGD and EUS revealed two esophageal wall ulcerations and two periesophageal mediastinal edemas only in the esophageal cooling group (P = .008). CONCLUSION: Esophageal cooling balloon strategy resulted in a higher RF power energy delivery when ablating at the LA posterior wall, using 8 mm nonirrigated tip catheters under temperature mode control. Despite that, patients presented a relatively low incidence of esophageal and periesophaeal injuries.

Radiofrequency catheter ablation of premature ventricular contractions originating in the right ventricular outflow tract.

OBJECTIVES: To evaluate if radiofrequency catheter ablation is an effective procedure for the treatment of right ventricular outflow tract premature ventricular contractions (RVOT-PVC) and ascertain if it results in an improvement of symptoms. METHODS: A prospective study with 30 consecutive patients (mean age 40 +/- 13 years, 25 females), with no apparent structural cardiopathy, with very frequent (mean density of 1,263 +/- 593/h) RVOT-PVC, symptomatic for more than one year (mean = 74 months) and resistant to antiarrhythmic drugs (3 +/- 1.7, including beta-blockers), who underwent radiofrequency catheter ablation. RESULTS: After the first procedure, there were 23 initial successful cases (76.6%) and 7 initial failures (23.4%). Four patients experienced relapses, two of whom did not undergo the second procedure. The second procedure was carried out in 9 patients (7 initial failures and 2 relapses), and there was success in 5 additional patients, one of them by epicardial access. The final success rate was 80% (24/30), and there were no major complications. After a mean follow-up of 14 +/- 6 months, in the successful group there was a reduction greater than 90% in density of premature ventricular contractions (PVC) (24/24; p<0.0001) and a resulting absence of symptoms in the majority of patients (23/24; p<0.001). CONCLUSION: Radiofrequency catheter ablation is a safe and effective treatment for patients with persistent and symptomatic PVC with RVOT morphology.

Ablation of typical atrial flutter: a prospective randomized study of cooled-tip versus 8-mm-tip catheters.

OBJECTIVES: Both ablation catheters with closed irrigated system and 8mm tip-catheters have been shown to be more effective for typical atrial flutter radiofrequency (RF) ablation when compared to conventional 4 mm tip catheter. Considering the differences in complexity and costs of both systems, a prospective study was designed to compare the efficacy and safety of cooled-tip and 8mm-tip catheters for atrial flutter ablation. METHODS: Fifty-two consecutive patients underwent RF ablation of cavotricupsid isthmus (CTI) for the treatment of typical atrial flutter, using catheter with closed irrigation system (n=26) or 8 mm-tip catheter (n=26). The RF pulses were applied point-by-point for 60 seconds, with power limited at 50 w for the irrigated catheter and by temperature control (60 degrees/70 w) for the 8 mm catheter. RESULTS: The CTI block was successfully performed in 98.1%. Four patients in the irrigated group needed to switch to the other group. There was no significant difference with regard to ablation parameters, such as total time of RF ablation (591.1+/-309.0 s vs 486.2+/-250.8 s), total procedure duration (86.4+/-23.6 vs 78.1+/-22.5 min) and time of fluoroscopy (17.0+/-6.7 vs 15.4+/-4.6 min). During follow-up of 10.6 months in average, one patient in the irrigated group had recurrence of typical atrial flutter. CONCLUSION: Efficacy and safety of CTI ablation was comparable between both techniques (irrigated catheter and 8 mm-tip catheter). The complexity of irrigated catheter makes it less competitive.

Ablação com radiofreqüência de extra-sístoles da via de saída do ventrículo direito / Radiofrequency catheter ablation of premature ventricular contractions originating in the right ventricular outflow tract

OBJETIVOS: Avaliar se a ablação com radiofreqüência é um procedimento eficiente para o tratamento das extra-sístoles da via de saída do ventrículo direito (EVSVD), e se resulta em melhora dos sintomas. MÉTODOS: Estudo prospectivo, com 30 pacientes consecutivos (idade média de 40±13 anos, 25 do sexo feminino), sem cardiopatia estrutural aparente, com EVSVD, muito freqüentes (densidade média de 1.263±593/h), sintomáticos por mais de 1 ano (média =74 meses) e refratários aos fármacos antiarrítmicos (3±1,7, incluindo os beta-bloqueadores), que foram submetidos à ablação com radiofreqüência. RESULTADOS: Após o primeiro procedimento, houve 23 sucessos iniciais (76,6 por cento) e 7 iniciais insucessos (23,4 por cento). Quatro pacientes tiveram recorrências, sendo que dois desses não se submeteram ao segundo procedimento. O segundo procedimento foi realizado em 9 pacientes (7 insucessos iniciais e 2 recorrências), e o sucesso ocorreu em 5 pacientes adicionais, sendo 1 caso por acesso epicárdico. A taxa de sucesso final foi de 80 por cento (24/30), e nenhuma complicação maior ocorreu. Após um seguimento médio de 14±6 meses, no grupo de sucesso final houve uma redução de mais de 90 por cento na densidade das extra-sístoles(24/24; p<0,0001) e resultante ausência de sintomas na maioria dos pacientes (23/24; p<0,001). CONCLUSÃO: A ablação com radiofreqüência é um tratamento seguro e eficaz para os pacientes com extra-sístoles persistentes e sintomáticas com morfologia do trato de saída do ventrículo direito.

OBJECTIVES: To evaluate if radiofrequency catheter ablation is an effective procedure for the treatment of right ventricular outflow tract premature ventricular contractions (RVOT-PVC) and ascertain if it results in an improvement of symptoms. METHODS: A prospective study with 30 consecutive patients (mean age 40 ± 13 years, 25 females), with no apparent structural cardiopathy, with very frequent (mean density of 1,263 ± 593/h) RVOT-PVC, symptomatic for more than one year (mean = 74 months) and resistant to antiarrhythmic drugs (3 ± 1.7, including beta-blockers), who underwent radiofrequency catheter ablation. RESULTS: After the first procedure, there were 23 initial successful cases (76.6 percent) and 7 initial failures (23.4 percent). Four patients experienced relapses, two of whom did not undergo the second procedure. The second procedure was carried out in 9 patients (7 initial failures and 2 relapses), and there was success in 5 additional patients, one of them by epicardial access. The final success rate was 80 percent (24/30), and there were no major complications. After a mean follow-up of 14 ± 6 months, in the successful group there was a reduction greater than 90 percent in density of premature ventricular contractions (PVC) (24/24; p<0.0001) and a resulting absence of symptoms in the majority of patients (23/24; p<0.001). CONCLUSION: Radiofrequency catheter ablation is a safe and effective treatment for patients with persistent and symptomatic PVC with RVOT morphology.

Ablação do flutter atrial típico: estudo prospectivo e randomizado do cateter irrigado fechado versus cateter com eletrodo distal de 8 mm / Ablation of typical atrial flutter: a prospective randomized study of cooled-tip versus 8-mm-tip catheters

OBJETIVOS: Trabalho prospectivo, randomizado para comparar a eficácia e a segurança do cateter irrigado em relação ao cateter com eletrodo distal de 8 mm para ablação com radiofreqüência (RF) do flutter atrial. MÉTODOS: Em 52 pacientes consecutivos referidos para tratamento do flutter atrial típico, a ablação do istmo cavotricuspídeo (Ist-CT) foi realizada com cateter de irrigação fechada (n=26) ou com cateter de eletrodo distal de 8 mm (n=26). Os pulsos de RF foram aplicados ponto a ponto por 60 segundos com potência limitada a 50 w com o cateter irrigado e por controle de temperatura (60°C, 70 w) com cateter de 8 mm. O critério de fim do procedimento foi a obtenção de bloqueio bidirecional do Ist-CT. RESULTADOS: O bloqueio Ist-CT foi obtido em 98,1 por cento dos pacientes. O "crossover" ocorreu em quatro pacientes do grupo com cateter irrigado. Não se encontrou diferença estatística significante em relação aos parâmetros da ablação, tais como tempo total de aplicação de RF (591,1±309,0s vs 486,2±250,8s), duração do procedimento (86,4 ± 23,6 vs 78,1±22,5min) e tempo de fluoroscopia (17,0±6,7 vs 15,4±4,6min) entre os dois grupos. Durante seguimento médio de 10,6 meses, um paciente do grupo irrigado apresentou recorrência do flutter atrial típico. CONCLUSÃO: A ablação do Ist-CT resultou ser efetiva e segura para o controle do flutter atrial com ambas as técnicas empregadas (cateter com eletrodo distal de 8 mm e cateter irrigado). A complexidade técnica do cateter irrigado proporciona menor competitividade.

OBJECTIVES: Both ablation catheters with closed irrigated system and 8mm tip-catheters have been shown to be more effective for typical atrial flutter radiofrequency (RF) ablation when compared to conventional 4 mm tip catheter. Considering the differences in complexity and costs of both systems, a prospective study was designed to compare the efficacy and safety of cooled-tip and 8mm-tip catheters for atrial flutter ablation. METHODS: Fifty-two consecutive patients underwent RF ablation of cavotricupsid isthmus (CTI) for the treatment of typical atrial flutter, using catheter with closed irrigation system (n=26) or 8 mm-tip catheter (n=26). The RF pulses were applied point-by-point for 60 seconds, with power limited at 50 w for the irrigated catheter and by temperature control (60°C / 70 w) for the 8mm catheter. RESULTS: The CTI block was successfully performed in 98.1 percent. Four patients in the irrigated group needed to switch to the other group. There was no significant difference with regard to ablation parameters, such as total time of RF ablation (591.1±309.0s vs 486.2±250.8s), total procedure duration (86.4±23.6 vs 78.1±22.5min) and time of fluoroscopy (17.0±6.7 vs 15.4±4.6min). During follow-up of 10.6 months in average, one patient in the irrigated group had recurrence of typical atrial flutter. CONCLUSION: Efficacy and safety of CTI ablation was comparable between both techniques (irrigated catheter and 8mm-tip catheter). The complexity of irrigated catheter makes it less competitive.