Catheter Ablation of Ventricular Tachycardia in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is predominantly an inherited cardiomyopathy with typical histopathological characteristics of fibro-fatty infiltration mainly involving the right ventricular (RV) inflow tract, RV outflow tract, and RV apex in the majority of patients. The above pathologic evolution frequently brings patients with ARVD/C to medical attention owing to the manifestation of syncope, sudden cardiac death (SCD), ventricular arrhythmogenesis, or heart failure. To prevent future or recurrent SCD, an implantable cardiac defibrillator (ICD) is highly desirable in patients with ARVD/C who had experienced unexplained syncope, hemodynamically intolerable ventricular tachycardia (VT), ventricular fibrillation, and/or aborted SCD. Notably, the management of frequent ventricular tachyarrhythmias in ARVD/C is challenging, and the use of antiarrhythmic drugs could be unsatisfactory or limited by the unfavorable side effects. Therefore, radiofrequency catheter ablation (RFCA) has been implemented to treat the drug-refractory VT in ARVD/C for decades. However, the initial understanding of the link between fibro-fatty pathogenesis and ventricular arrhythmogenesis in ARVD/C is scarce, the efficacy and prognosis of endocardial RFCA alone were limited and disappointing. The electrophysiologists had broken through this frontier after better illustration of epicardial substrates and broadly application of epicardial approaches in ARVD/C. In recent works of literature, the application of epicardial ablation also successfully results in higher procedural success and decreases VT recurrences in patients with ARVD/C who are refractory to the endocardial approach during long-term follow-up. In this article, we review the important evolution on the delineation of arrhythmogenic substrates, ablation strategies, and ablation outcome of VT in patients with ARVD/C.

Epicardial Ablation of Ventricular Tachycardia: a Review

For over 3 decades, it has been known that reentry circuits for ventricular tachycardia (VT) are not limited to the subendocardial myocardium. Rather, intramural or subepicardial substrates may also give rise to VT, particularly in those with non-ischemic cardiomyopathy. Percutaneous epicardial mapping and ablation has been successfully introduced for the treatment of such subepicardial VT. Herein, we review the indications for epicardial ablation and the identification of epicardial VT by electrocardiographic and imaging modalities. We also discuss the optimal technique for epicardial access and the implications of epicardial fat which has the potential to mimic scar, decreasing the specificity of electrogram morphology and impeding energy delivery to the tissue. Finally, we also report on possible complications of the procedure and strategies to mitigate adverse events.

Asociación del tejido adiposo epicárdico con la fibrilación auricular y su pronóstico posterior a la ablación de venas pulmonares / Association of epicardial adipose tissue with atrial fibrillation and prognosis following pulmonary vein ablation

Resumen Introducción: la acumulación de tejido adiposo epicárdico se asocia con obesidad y aumento en la prevalencia, severidad y recurrencia posteriores a la ablación de la fibrilación auricular. Dentro de los mecanismos implicados se considera un estado proinflamatorio que lleva al remodelamiento estructural de la aurícula y a la alteración en las propiedades electrofisiológicas de los miocitos auriculares. Hasta la fecha no se ha estudiado este fenómeno en Colombia. Objetivo: demostrar esta asociación en un grupo de pacientes de nuestra población a quienes se les realizó ablación de venas pulmonares por radiofrecuencia. Materiales y métodos: se revisaron 170 angiotomografías de corazón realizadas previamente a la ablación de venas pulmonares en pacientes con antecedente de fibrilación auricular. Los pacientes con datos incompletos fueron excluidos para el análisis, 94 fueron analizados. Se cuantificó el grosor del tejido adiposo epicárdico y en conjunto con el índice de masa corporal se analizó su relación con los subtipos de fibrilación auricular, así como recaídas luego de la ablación. Resultados: la mayoría de la población se encontró con sobrepeso y obesidad. Tanto los pacientes obesos como aquellos con sobrepeso, tuvieron significativamente grosor mayor de tejido adiposo epicárdico total respecto a los pacientes con índice de masa corporal normal (p = 0,01). El grosor de la grasa epicárdica fue significativamente mayor en fibrilación auricular persistente respecto a la fibrilación auricular paroxística (p = 0,01). En los pacientes que presentaron recaídas no se observó una diferencia significativa pero sí una tendencia a tener mayor tejido adiposo epicárdico total (p = 0,08). El aumento del tamaño auricular se relacionó en forma significativa con el grosor del tejido adiposo epicárdico (p = 0,05). En el análisis de regresión logística multivariable mantuvo esta relación. Conclusiones: el aumento del tejido adiposo epicárdico se relaciona de manera independiente con el sobrepeso y la obesidad, así como con la severidad y el pronóstico de la fibrilación auricular. Deben hacerse estudios prospectivos de cohortes en los que se evalúe y establezcan valores de corte normales para nuestra población, al igual que seguimiento a largo plazo de la evolución posterior a ablación de venas pulmonares y a intervenciones como disminución de peso.

Abstract Introduction: Accumulation of epicardial adipose tissue is associated with obesity and an increase of prevalence, severity and recurrence following ablation of atrial fibrillation. Within the implicated mechanisms, a proinflammatory state is considered when it leads to the structural remodelling of the atrium and to the alteration of the electrophysiological properties of atrial myocytes. So far this phenomenon has not been studied in Colombia. Motivation: To prove the association in a group of patients of our population who underwent radiofrequency ablation of pulmonary veins. Material and methods: 170 coronary CT angiographies were reviewed prior to the pulmonary vein ablation in patients with a history of atrial fibrillation. Patients with incomplete data were excluded from the analysis, 94 were analysed. Epicardial adipose tissue thickness and body mass index were measured, and their relationship with atrial fibrillation subtypes was assessed, as well as relapses following the ablation. Results: Most participants were overweight or obese. Both obese and overweight patients had a significantly thicker total epicardial adipose tissue than those with a normal body mass index (p = 0.01). The thickness of epicardial fat was significantly higher in persistent atrial fibrillation in comparison with paroxysmal atrial fibrillation (p = 0.01). Patients with relapses did not show a significant difference but they did have a higher tendency to greater total epicardial adipose tissue. The increase in atrial size was significantly relates to the thickness of epicardial adipose tissue (p = 0.05). Multivariate logistic regression analysis kept this relationship. Conclusions: The increase in epicardial adipose tissue is independently related to being overweight and obese, as well as to severity and prognosis of atrial fibrillation. Prospective cohort studies must be conducted where normal cut-off values for our population group are assessed and established, and the long-term progress following pulmonary vein ablation and other procedures such as weight loss surgery is followed.

Avaliação intraoperatória de contratilidade miocárdica com eletrodo decapolar / Intraoperative evaluation of myocardial contractility with decapolar catheter

Atualmente, temos a disposição modernas técnicas de mapeamento eletroanatômico gerando imagens tridimensionais da propagação do impulso nas câmaras cardíacas através de catéteres endocavitários. Apesar disso, poucos estudos estão disponíveis a respeito do mapeamento eletrofisiológico epicárdico. A avaliação intraoperatória de contratilidade miocárdica imediatamente após a revascularização miocárdica é visual e Ecocardiográfica, porém este é muito pouco utilizado para este fim. Há, portanto, a necessidade de desenvolvimento de novos métodos capazes de avaliar o impacto funcional da revascularização miocárdica. Objetivo: Avaliar a resposta intra-operatória de contratilidade miocárdica regional mediante o mapeamento epicárdico com eletrodo decapolar. Métodos: 20 pacientes serão submetidos a revascularização miocárdica e será realizado o mapeamento epicárdico com eletrodo decapolar após confecção da anastomose distal com perfusão seletiva para área revascularizada com a aorta pinçada e portanto sem perfusão para as demais artérias coronárias. Nesta análise será avaliado a duração do impulso do eletrograma...

Analysis of the Rhythm of Atrial Epicardial Mapping Data Based on Dominant Frequency / 中国医疗器械杂志

If heart function is normal, the atrial cells are excited in a stable rhythm. But this would change during atrial fibrillation. In this paper, after comparing with the method of characteristic point, we use the dominant frequency method to analyze the activation pattern under sinus and atrial fibrillation rhythm in different parts of atria based on epicardial mapping system. It is found that the activation rhythm changes a lot in different parts of atria, and the automaticity of atrial cells change obviously in somewhere. The result shows that dominant frequency method is very suitable for the analysis of atrial fibrillation signal. What's more, we also roughly discuss the role of this method in exploring the driving sources during atrial fibrillation.

Mapeamento epicárdico da taquicardia ventricular sustentada em cardiopatias não isquêmicas / Epicardial mapping of sustained ventricular tachycardia in nonischemic heart disease / Mapeo epicárdico de la taquicardia ventricular sostenida en cardiopatías no isquémicas

FUNDAMENTO: A complexidade dos circuitos reentrantes relacionados às taquicardias ventriculares diminui os índices de sucesso dos procedimentos de ablação por radiofrequência. OBJETIVO: Avaliar se o mapeamento epicárdico com múltiplos eletrodos realizado simultaneamente com o mapeamento endocárdico auxilia na ablação da taquicardia ventricular (TV) sustentada em pacientes com cardiopatia não isquêmica. MÉTODOS: Vinte e seis pacientes com TV sustentada recorrente, sendo 22 (84,6 por cento) com cardiopatia chagásica crônica, dois (7,7 por cento) com cardiomiopatia dilatada idiopática e dois (7,7 por cento) portadores de displasia arritmogênica do ventrículo direito, foram submetidos a mapeamento epicárdico com dois ou três microcateteres, com 8 eletrodos cada, simultaneamente ao mapeamento endocárdico convencional. Utilizou-se cateter com ponta de 4 mm para ablação com radiofrequência (RF) realizada durante a TV induzida. RESULTADOS: Das 33 TVs induzidas, 25 foram mapeadas e 20 tiveram sua origem definida. Onze com origem epicárdica e 9 endocárdica. A estimulação ventricular programada não induziu TV sustentada em 11 (42,0 por cento) dos 26 pacientes após a ablação. Eventos como recorrência da TV e morte ocorreram em 10,0 por cento dos pacientes submetidos à ablação com sucesso, e em 59,0 por cento dos insucessos, em seguimento ambulatorial médio de 357 ± 208 dias. CONCLUSÃO: Circuitos subepicárdicos são frequentes em pacientes com cardiopatia não isquêmica. O mapeamento epicárdico com múltiplos cateteres realizado simultaneamente com o mapeamento endocárdico contribui para a identificação destes circuitos em um mesmo procedimento.

BACKGROUND: The complexity of reentrant circuits related to ventricular tachycardias decreases the success rate of radiofrequency ablation procedures. OBJECTIVE: To evaluate whether the epicardial mapping with multiple electrodes carried out simultaneously with the endocardial mapping helps in ablation procedures of sustained ventricular tachycardia (VT) in patients with nonischemic heart disease. METHODS: Twenty-six patients with recurrent sustained VT, of which 22 (84.6 percent) presenting chronic chagasic cardiomyopathy, 2 (7.7 percent) with idiopathic dilated cardiomyopathy and 2 with right ventricular arrhythmogenic dysplasia (RVAD), were submitted to epicardial mapping with two or three microcatheters, with 8 electrodes each, simultaneously to the conventional endocardial mapping. A catheter with a 4-mm tip was used for the ablation by radiofrequency (RF) carried out during the induced VT. RESULTS: Of the 33 induced VT, 25 were mapped and 20 had their origin defined. Eleven had epicardial and 9 had endocardial origin. The programmed ventricular stimulation did not induce sustained VT in 11 (42.0 percent) of the 26 patients after the ablation. Events such as VT recurrence and death occurred in 10.0 percent of the patients submitted to successful ablation and in 59.0 percent of the unsuccessful cases, during a mean ambulatory follow-up of 357 ± 208 days. CONCLUSION: Subepicardial circuits are frequent in patients with nonischemic heart disease. The epicardial mapping with multiple catheters carried out simultaneously with the endocardial mapping contributes to the identification of these circuits in a same procedure.

FUNDAMENTO: La complejidad de los circuitos reentrantes relacionados a las taquicardias ventriculares disminuye los índices de éxito de los procedimientos de ablación por radiofrecuencia. OBJETIVO: Evaluar si el mapeo epicárdico con múltiples electrodos realizado simultáneamente con el mapeo endocárdico ayuda en la ablación de la taquicardia ventricular (TV) sostenida en pacientes con cardiopatía no isquémica. MÉTODOS: Veinte y seis pacientes con TV sostenida recurrente, siendo 22 (84,6 por ciento) con cardiopatía chagásica crónica, dos (7,7 por ciento) con cardiomiopatía dilatada idiopática y dos (7,7 por ciento) portadores de displasia arritmogénica del ventrículo derecho, fueron sometidos a mapeo epicárdico con dos o tres microcatéteres, con 8 electrodos cada uno, simultáneamente al mapeo endocárdico convencional. Se utilizó catéter con punta de 4 mm para ablación con radiofrecuencia (RF) realizada durante la TV inducida. RESULTADOS: De las 33 TVs inducidas, 25 fueron mapeadas y 20 tuvieron su origen definido. Once con origen epicárdica y 9 endocárdica. La estimulación ventricular programada no indujo TV sostenida en 11 (42,0 por ciento) de los 26 pacientes después de la ablación. Eventos como recurrencia de la TV y muerte ocurrieron en 10,0 por ciento de los pacientes sometidos a la ablación con éxito, y en 59,0 por ciento de los fracasos, en control ambulatorio medio de 357 ± 208 días. CONCLUSIÓN: Circuitos subepicárdicos son frecuentes en pacientes con cardiopatía no isquémica. El mapeo epicárdico con múltiples catéteres realizado simultáneamente con el mapeo endocárdico contribuye a la identificación de estos circuitos en un mismo procedimiento.

An adaptive filtering algorithm applied to inhibit the interference from the ventricular during atrial epicardial mapping experiment / 中国医疗器械杂志

This paper introduces an adaptive filtering algorithm based on the LMS principle to inhibit the ventricular interference in the atrial epicardial mapping experiments.

The analysis of atrial cells conductivity based on epicardial mapping data of dog / 中国医疗器械杂志

This paper discusses the law of atrial electrical activity propagation (the timing of signal and the conduction velocity) under the sinus rhythm before and after AF caused by high-frequency electrical stimulation. The paper analyzes how different doses of acetylcholine affect the conductivity of the atrial cells of dogs. This result can also help the diagnoses and treatment of human's AF.

The development for real-time sampling and display in epicardial mapping system / 中国医疗器械杂志

In order to realize real-time sampling and display in 128-channeled Epicardial Mapping System whose sampling frequency is 2 kHz per channel, the article introduces a mapping software and preliminarily validates its practicability. The software is designed in MFC, using multiple-thread technology and buffering and pumping values method.

A denoising method of epicardial potential mapping signals based on ICA / 中国医疗器械杂志

A new denoising method is presented in the paper, based on the independent component analysis(ICA) and the noise independent component selection measurement which is the dispersivity of the independent component's projection coefficients to each electrode. The results indicate that the method can denoise EPM signals with giving prominence to electrodes' true depolarization signals. So it' s fit well for the EPM system.

Radiofrequency ablation of ventricular tachycardia in post myocardial infarction patients: Kuwait experience

We evaluated prospectively 5 patients with previous myocardial infarction who had ventricular tachycardia. The objective of this study was to describe the arrhythmogenic areas and ablate the ischemic VT successfully with multiple radiofrequency applications. All patients were considered eligible irrespective of the presence of Automatic implantable cardioverter-defibrillator implants. Coronary artery bypass graft was performed for two patients. One patient had developed ventricular tachycardia/ventricular fibrillation post surgery requiring radiofrequency ablation followed by AICO implantation. Three patients with ischemic cardiomyopathy, who had AICO, developed VT prior to the radio frequency ablation therapy. In 5 patients with ventricular tachyarrhythmias three dimensional mapping was performed using non contact mapping [EnSite]. RF ablations targeted the arrhythmogenic areas of infarcted zone. All patients were rendered completely non inducible at the end of the procedure. The mean procedure time measured was 3 hours. No complications were observed in any of those patients. On follow up, all patients improved clinically with regard to the quality of life and number of AICD shocks. One post AICD patient had non sustained ventricular tachycardia, during the follow up period. This is a limited study of our local experience in the successful radio frequency ablation of ischemic ventricular tachycardia

The application of multilevel B-splines in 3D emulation of dynamic epicardium mapping / 中国医疗器械杂志

This paper presents an algorithm for data interpolation and approximation used in the whole atria mapping. Multilevel B-splines are introduced to compute the whole atria surface through a set of irregularly spaced points and to draw the 3D isopotential map, which can reflect the conduction process of depolarization in complex arrhythmia such as atrial fibrillation.

Experimental Study on Ventricular Fusion in Wolff-Parkinson-White Syndrome

WPW syndrome is the most common variaty of preexcitaton syndrome in which whole or part of ventricular muscle is activated by the atrial impulse earlier than would be expected if the impulse reached the ventricle by way of normal conduction system alone. WPW syndrome result from existence of accessory muscle bridge(atrio ventricular connection) between atrium and ventricle. The ventricular complex observed in WPW syndrome during periods of sinus rhythm is the result of fusion, with intial phase of ventricular activation representing excitation via accessory pathway and later forces produced by excitation of residual portions of ventricle via normal His-purkinje system. The variations in QRS aberrancy in WPW syndrome depend on varying degree of preexcitation. This experimental study was undertaken to increase our knowledge on the ventricular fusion in WPW syndrome through epicardial mapping after experimental induction of ventricular preexcitaion of WPW type. In 5 normal dogs, the heart was widely exposed through transverse thoracotomy and positioned in a pericardial cradle, then electric wires were fixed on the epicardium of right atrium and ventricular bases(anterobasal and posterobasal) areas of right ventricle, anterobasal and poaterobasal areas of left ventricle for atrial and ventricular pacing. Epicardial mapping was then performed during atrial pacing alone and during atrioventricular sequential pacing at the same rate. Atrioventricular sequential pacing was done with various short AV intervals(60-110 msec) for the purpose of premature stimulation on ventricular base. In mapping we used the grid system which consisted of 29 areas to cover the right ventricle and 23 areas to cover the left ventricle. We drew 9 epicardial ishochrone maps in 5 dogs. The epicardial data during atrio-ventriclar sequential pacing were then compared with those during atrial pacing at an identical rate to study the ventricular fusion in WPW syndrome. The results were as follows; 1) The preexciting wave spread radially from the stimulated basal area to the right and left(or anterior and posterior wall) and the apex. 2) Preexciting wavefronts collided with the normal wavefronts in a wide range of ventricular activation time. 3) Preexcitation widened according to the degree of the shortening of the AV interval. 4) The duration of ventricular activation was greater in preexcited ventricles than in normally activated ventricles. The more prematurely the ventricle was stimulated, the greater the duration of ventricular activation was.