Ablação por Cateter de Taquicardia Atrial Focal com Ativação Precoce Próxima ao Feixe de His, a Partir da Cúspide Aórtica não Coronária / Catheter Ablation of Focal Atrial Tachycardia with Early Activation Close to the His-Bundle from the Non Coronary Aortic Cusp

Resumo Fundamento A ablação da taquicardia atrial (TA) com local de ativação mais precoce próxima ao feixe de His é um desafio, devido ao risco de bloqueio de AV completo por sua proximidade ao sistema de His-Purkinje (SHP). Uma alternativa para minimizar esse risco é posicionar o cateter na cúspide não coronária (CNC), que é anatomicamente contígua à região para-Hissiana. Objetivos O objetivo deste estudo foi fazer uma revisão de literatura e avaliar as características eletrofisiológicas, a segurança e o índice de sucesso de aplicação de radiofrequência (RF) por cateter na CNC para o tratamento de TA para-Hissiana em uma série de casos. Métodos Avaliamos retrospectivamente dez pacientes (Idade: 36±10 anos) que foram encaminhados para ablação de taquicardia paroxística supraventricular (TPSV) e haviam sido diagnosticados com TA focal para-Hissiana confirmada por manobras eletrofisiológicas clássicas. Para a análise estatística, um P valor d <0.05 foi considerado estatisticamente significativo. Resultados A ativação atrial mais precoce na posição His foi de 28±12ms da onda P, e a CNC foi 3±2ms antes da posição His, sem evidência de potencial His em todos os pacientes. Foi aplicada RF à CNC (cateter de ponta de 4-mm; 30W, 55°C) e a taquicardia foi interrompida em 5±3s sem aumento no intervalo PR ou evidência de um ritmo juncional. Os testes eletrofisiológicos não induziram novamente a taquicardia em 9/10 pacientes. Não houve complicações em nenhum procedimento. Durante o período de acompanhamento de 30 ± 12 meses, nenhum paciente apresentou recorrência de taquicardia. Conclusão O tratamento percutâneo de TA para-Hissiana por meio de CNC é uma estratégia segura e eficiente, tornando-se uma opção interessante para o tratamento de arritmia complexa. (Arq Bras Cardiol. 2021; 116(1):119-126)

Abstract Background Atrial tachycardia (AT) ablation with earliest activation site close to the His-Bundle is a challenge due to the risk of complete AV block by its proximity to His-Purkinje system (HPS). An alternative to minimize this risk is to position the catheter on the non-coronary cusp (NCC), which is anatomically contiguous to the para-Hisian region. Objectives The aim of this study was to perform a literature review and evaluate the electrophysiological characteristics, safety, and success rate of catheter-based radiofrequency (RF) delivery in the NCC for the treatment of para-Hisian AT in a case series. Methods This study performed a retrospective evaluation of ten patients (Age: 36±10 y-o) who had been referred for SVT ablation and presented a diagnosis of para-Hisian focal AT confirmed by classical electrophysiological maneuvers. For statistical analysis, a p-value of <0.05 was considered statistically significant. Results The earliest atrial activation at the His position was 28±12ms from the P wave and at the NCC was 3±2ms earlier than His position, without evidence of His potential in all patients. RF was applied on the NCC (4-mm-tip catheter; 30W, 55ºC), and the tachycardia was interrupted in 5±3s with no increase in the PR interval or evidence of junctional rhythm. Electrophysiological tests did not reinduce tachycardia in 9/10 of patients. There were no complications in all procedures. During the 30 ± 12 months follow-up, no patient presented tachycardia recurrence. Conclusion The percutaneous treatment of para-Hisian AT through the NCC is an effective and safe strategy, which represents an interesting option for the treatment of this complex arrhythmia. (Arq Bras Cardiol. 2021; 116(1):119-126)

Safety and results of bioelectrical impedance analysis in patients with cardiac implantable electronic devices

Abstract Objective: To analyze the dual interference between cardiac implantable electronic devices (CIEDs) and bioelectrical impedance analysis (BIA). Methods: Forty-three individuals admitted for CIEDs implantation were submitted to a tetrapolar BIA with an alternating current at 800 microA and 50 kHz frequency before and after the devices' implantation. During BIA assessment, continuous telemetry was maintained between the device programmer and the CIEDs in order to look for evidence of possible electric interference in the intracavitary signal of the device. Results: BIA in patients with CIEDs was safe and not associated with any device malfunction or electrical interference in the intracardiac electrogram of any electrode. After the implantation of the devices, there were significant reductions in BIA measurements of resistance, reactance, and measurements adjusted for height resistance and reactance, reflecting an increase (+ 1 kg; P<0.05) in results of total body water and extracellular water in liter and, consequently, increases in fat-free mass (FFM) and extracellular mass in kg. Because of changes in the hydration status and FFM values, without changes in weight, fat mass was significantly lower (-1.2 kg; P<0.05). Conclusion: BIA assessment in patients with CIEDs was safe and not associated with any device malfunction. The differences in BIA parameters might have occurred because of modifications on the patients' body composition, associated to their hydration status, and not to the CIEDs.

Mapeo y ablación exitosa, desde el interior de la vena cardíaca magna, de extrasístoles ventriculares originados en el techo (summit) del ventrículo izquierdo / Mapping and successful ablation, from within the great cardiac vein, of premature ventricular contractions originating from the summit of the left ventricle

RESUMEN Se presenta el caso de una paciente de 43 años, con antecedentes de salud aparente, hasta varias semanas previas a su ingreso, cuando comenzó a presentar síncopes precedidos de palpitaciones. Se realizó estudio electrofisiológico y se demostró precocidad en la porción distal del electrodo de registro de seno coronario, que corresponde a la vena cardíaca magna (interventricular anterior) y techo (summit) del ventrículo izquierdo. A pesar del excelente registro precoz se estudiaron estructuras vecinas como el tracto de salida del ventrículo izquierdo en la cúspide coronaria izquierda, aquí el mapeo eléctrico (pace mapping) no fue concordante total. En el sitio de la precocidad obtenida dentro del sistema venoso cardíaco se realizó mapeo concordante 100%, con una precocidad del catéter de ablación de -30 milisegundos. Se decidió ablación con incrementos progresivos de temperatura y potencia con corte de impedancia (termomapping) y se logró el éxito de la ablación sin reproducibilidad de la arritmia y excelente evolución posterior.

ABSTRACT The case of a 43-year-old female patient is presented, with an apparent history of good health, up to several weeks prior to admission, when she began to present syncopes preceded by palpitations. An electrophysiological study was performed and prematurity in the distal portion of the coronary sinus recording electrode was demonstrated, which corresponds to the great cardiac vein (anterior interventricular vein) and summit of the left ventricle. Despite the excellent early registration, neighboring structures were studied, such as the left ventricular outflow tract in the left coronary cusp, here the pace mapping was not totally concordant. At the site of the precocity obtained within the cardiac venous system, a 100% concordant mapping was achieved, with an ablation catheter's precocity of -30 milliseconds. The ablation was decided with progressive increases in temperature and power with thermomapping and the success of the ablation was achieved without reproducibility of the arrhythmia and excellent subsequent evolution.

Paroxysmal Atrial Fibrillation Catheter Ablation Outcome Depends on Pulmonary Veins Anatomy / O Resultado da Ablação por Cateter da Fibrilação Atrial Paroxística Depende da Anatomia das Veias Pulmonares

Abstract Background: Pulmonary veins (PV) are often the trigger to atrial fibrillation (AF). Occasionally, left PVs converge on a common trunk (LCT) providing a simpler structure for catheter ablation. Objective: To compare the clinical characteristics and outcomes of ablation in paroxysmal atrial fibrillation (PAF) of patients with or without LCT. Methods: Case-control study of patients undergoing first-ever catheter ablation procedure for drug refractory PAF. The information was taken from patients' records by means of a digital collection instrument, and indexed to an online database (Syscardio(r)). Clinical characteristics and procedures were compared between patients with or without LCT (LCT x n-LCT), adopting a level of statistical significance of 5%. The primary endpoint associated with efficacy was lack of atrial arrhythmia over the follow-up time. Results: One hundred and seventy two patients with PAF were included in the study, 30 (17%) LCT and 142 (83%) n-LCT. The clinical characteristics, comorbidities, symptoms scale and risk scores did not differ between the groups. There was AF recurrence in 27% of PAF patients in the n-LCT group and only 10% of patients in the LCT group (OR: 3.4 p: 0.04) after a follow-up of 34 ± 17 months and 26 ± 15 months respectively. Conclusion: Patients with a LCT have a significantly lower recurrence rate when compared to patients without this structure. It is mandatory to report the results of AF catheter ablation as a PV anatomical variation function.

Resumo Fundamento: As veias pulmonares (VP) são frequentemente o local de origem da fibrilação atrial (FA). Ocasionalmente, as VPs esquerdas confluem em um tronco comum (TrCE) proporcionando uma estrutura mais simples para ablação por cateter. Objetivos: Tem-se como objetivo comparar as características clínicas e os resultados da ablação em pacientes portadores de FA paroxística (FAP) com ou sem TrCE. Metódos: Estudo do tipo caso-controle de pacientes submetidos ao primeiro procedimento de ablação por cateter para FAP refratária a drogas antiarrítmicas. As informações foram retiradas dos prontuários dos pacientes por meio de instrumento digital de coleta e indexadas a uma base de dados online (Syscardio(r)). As características clínicas e procedimentos foram comparados entre pacientes com e sem TrCE (TrCE x n-TrCE), sendo adotado nível de significância estatística de 5%. O desfecho primário associado à eficácia foi ausência de arritmia atrial ao longo do seguimento com único procedimento. Resultados: Cento e setenta e dois pacientes foram incluídos no estudo, 30 (17%) TrCE e 142 (83%) n-TrCE. As características clínicas, comorbidades, severidade de sintomas e escores de risco não apresentaram diferença estatística entre os grupos. Houve recorrência da FA em 27% dos pacientes do grupo não-TrCE e em apenas 10% dos pacientes do grupo TrCE (OR: 3,4 p: 0.04) após um seguimento de 34±17 e 26±15 meses respectivamente. Conclusão: Pacientes com TrCE apresentam significativamente menor taxa de recorrência quando comparados a pacientes sem esta estrutura. É imprescindível relatar os resultados da ablação por cateter de FA na vigência de variações anatômicas das VPs.

Resultados del estudio electrofisiológico y ablación en niños de hasta 13 años con técnica mínimamente invasiva

El estudio electrofisiológico (EEF) y la ablación en niños son eficaces y están internacionalmente bien pautados. Clásicamente se utilizan tres a cinco accesos vasculares y catéteres endovasculares (CEVs). Propusimos un protocolo simplificado para reducir la cantidad y con ello las complicaciones. Quisimos evaluar los resultados obtenidos. Material y método: realizamos un estudio descriptivo, prospectivo, longitudinal, de 120 pacientes consecutivos de hasta 13 años, sin cardiopatía estructural. El protocolo se basa en utilizar un registro esofágico (RIE) cuando es de utilidad, tener la imagen radiológica en pantalla de la posición del His e ir moviendo un CEV a la posición necesaria cada momento. Resultados: la edad osciló entre 7 meses y 13 años (media=9,5 años) y 72 (62%) eran varones. En 101 (84%) se intentó una ablación y en 19 (16%) EEF. El 70% de las ablaciones fueron por una vía accesoria, 25% por una reentrada nodal y 5% otras causas. El tiempo total de procedimiento fue 104 ± 55 minutos. En 58 niños se intentó RIE y en 57 se logró. El 42% de las ablaciones se hicieron con un solo acceso y 94% con uno o dos CEVs. En seis casos complejos se requirieron tres CEVs y en ninguno, cuatro. Hubo 15 que requirieron más de dos accesos. La ablación fue efectiva en 94%, y seguidos 51±22 meses hubo 6 (6%) recurrencias. Un paciente hizo una pericarditis, no hubo complicaciones vasculares, eléctricas ni otras. Conclusiones: con este protocolo se obtuvieron resultados similares a las series convencionales, con un número muy bajo de accesos, catéteres y complicaciones.

Summary: The electrophysiology study (EPS) and ablation procedure in children are effective and internationally well-defined techniques. They typically use 3 to 5 vascular accesses and endovascular catheters (EVC). We proposed a simplified protocol to reduce these numbers and thus, reduce complications. The study aimed to evaluate the results obtained. Method: we performed a descriptive, prospective, longitudinal study over 120 consecutive patients up to 13 years of age, with no structural heart disease. The protocol consists in using an esophageal record (IER) when it is useful, having the radiological image of its position on the screen and in continuing to move an EVC to the required position at each time. Results: age ranged between 7 months and 13 years (mean = 9.5) and 72 (62%) children were male. In 101 (84%) an ablation was attempted and in 19 (16%) EPS. 70% of the ablations were done for accessory pathways, 25% for nodal reentry tachycardia and 5% others causes. The total time of the procedure was 104 ± 55 minutes. In 58 children an IAR was attempted and in 57 it was achieved. In 42% of cases the ablation was made with 1 single access and 94% with 1 or 2 EVCs. In 6 complex cases 3 EVCs were required and 4 in none. There were 15 cases that required >2 accesses. The ablation was effective in 94%. During 51 ± 22 months of follow-up there were 6 (6%) recurrences. One patient had pericarditis, there were no vascular, electrical, or other complications. Conclusions: with this protocol the results are similar to the conventional series, using a very low number of accesses, catheters and complications rate.

O estudo eletrofisiológico (EPS) e a ablação em crianças são procedimentos eficazes e internacionalmente bem estabelecidos. Tipicamente utilizam-se 3 a 5 acessos vasculares e cateteres endovasculares (CEVs). Propusemos um protocolo simplificado para reduzir a quantidade e com isso as complicações com o fim de avaliar os resultados obtidos. Métodos: realizou-se um estudo longitudinal descritivo, prospectivo, de 120 pacientes consecutivos com até 13 anos de idade, sem cardiopatia estrutural. O protocolo consiste na utilizacao dum registro esofágico (EIR) quando resultar útil, uma imagem radiológica na tela que mostra posição de His e a movimentacao do CEV para a posição necessária a cada momento. Resultados: a idade variou de 7 meses a 13 anos (média = 9,5 anos). 72 (62%) dos pacientes eram do sexo masculino. 101 (84%) pacientes receberam uma ablação e 19 (16%) o FES. 70% das ablações foram por via acessória, 25% por reentrada nodal e 5% por outras causas. O tempo total do procedimento foi de 104 ± 55 minutos. O RIE se tentou em 58 crianças e se conseguiu em 57. 42% das ablações foram feitas com 1 acesso único e 94% com 1 ou 2 CEVs. Em 6 casos complexos, foram necessários 3 CEVs e em nenhum caso foram necessários 4. 15 casos necessitaram de mais de 2 acessos. A ablação foi eficaz em 94% dos casos e, após do seguimento de 51 ± 22 meses, houve 6 (6%) recorrências. Um paciente apresentou pericardite, más sem complicações vasculares, elétricas ou de outro tipo. Conclusões: obtivemos resultados semelhantes com este protocolo para as séries convencionais, com um número muito baixo de acessos, cateteres ou complicações.

Taquicardias supraventriculares. Estado del arte / Supraventricular tachycardia. State of the art

Las taquicardias supraventriculares son un grupo de entidades clínicas prevalentes en la población general, pero que afectan con mayor frecuencia a la población adulta; son ritmos rápidos y generalmente regulares en los cuales se encuentra implicada alguna estructura por encima de la bifurcación del haz de His para formación o perpetuación. El diagnóstico de estas entidades requiere un abordaje clínico sistemático, siendo el electrocardiograma de superficie la principal herramienta para su adecuada clasificación. El tratamiento de las taquicardias supraventriculares dependerá del estado hemodinámico del paciente, el cual definirá el requerimiento de terapia eléctrica o tratamiento médico. Se debe hacer una selección adecuada de los pacientes que requieren estudio electrofisiológico y ablación.

Supraventricular tachycardias are a set of clinical entities prevalent in the general population, but it is the adult population the most frequently affected by them. They are fast and usually regular rhythms in which some structures involved over the bundle of His bifurcation for its formation or maintenance are found. The diagnosis of these entities requires a systematic clinical approach being the surface electrocardiogram the main tool for their proper classification. Treatment of supraventricular tachycardias depends on the patient´s hemodynamic status, which will define the need of electrical therapy or medical treatment. An appropriate selection of patients requiring electrophysiological study and ablation should be made.

Electrophysiological Studies and Radiofrequency Ablations in Children and Adolescents with Arrhythmia / Estudos Eletrofisiológicos e Ablações com Radiofrequência em Crianças e Adolescentes com Arritmia

Background: Radiofrequency ablation is the standard non-pharmacological treatment for arrhythmias in pediatric patients. However, arrhythmias and their associated causes have particular features in this population. Objective: To analyze the epidemiological characteristics and findings of electrophysiological diagnostic studies and radiofrequency ablations in pediatric patients referred to the Electrophysiology Unit at Instituto de Cardiologia do Rio Grande do Sul, in order to characterize the particularities of this population. Methods: Cross-sectional study with 330 electrophysiological procedures performed in patients aged less than 20 years between June 1997 and August 2013. Results: In total, 330 procedures (9.6% of the overall procedures) were performed in patients aged less than 20 years (14.33 ± 3.25 years, age range 3 months to 19 years), 201 of which were males (60.9%). A total of 108 (32.7%) electrophysiological diagnostic studies were performed and of these, 48.1% showed abnormal findings. Overall, 219 radiofrequency ablations were performed (66.3%) with a success rate of 84.8%. The presence of an accessory pathway was the most prevalent finding, occurring in 158 cases (72.1%), followed by atrioventricular nodal reentrant tachycardia (16.8%), typical atrial flutter (3.1%) and extrasystoles originating from the right ventricular outflow tract (2.7%). Three patients developed complications during ablation (1.4%). Among congenital heart diseases, which occurred in 51 (15.4%) patients, atrial sept defect was the most frequent (27.4%), followed by ventricular sept defect (25.4%) and Ebstein's anomaly (17.6%). Conclusion: Electrophysiological study and radiofrequency ablation are effective tools for diagnosis and treatment of arrhythmias in the pediatric population. .

Fundamento: A ablação com radiofrequência é o tratamento não farmacológico de eleição para arritmias na população pediátrica. Porém, as arritmias e suas causas apresentam características particulares nesta população. Objetivos: Analisar as características epidemiológicas e os achados de estudo eletrofisiológico diagnóstico e ablação com radiofrequência na população pediátrica encaminhada à Eletrofisiologia do Instituto de Cardiologia do Rio Grande do Sul, a fim de caracterizar as suas particularidades. Resultados: Foram realizados 330 procedimentos (9,6% do total de procedimentos) em pacientes com idade inferior a 20 anos (14,33 ± 3,25 anos, variação entre 3 meses e 19 anos), dos quais 201 eram do sexo masculino (60,9%). Foram realizados 108 (32,7%) exames eletrofisiológicos diagnósticos e destes, 48,1% apresentaram anormalidades em seus achados. Ao todo, 219 ablações com radiofrequência foram realizadas (66,3%), obtendo-se sucesso em 84,8%. A presença de feixe acessório foi o achado mais prevalente, responsável por 158 casos (72,1%), seguida de taquicardia por reentrada nodal atrioventricular (16,8%), flutter atrial típico (3,1%) e extrassístole de via de saída de ventrículo direito (2,7%). Três pacientes apresentaram complicações durante a ablação (1,4%). Cardiopatia congênita esteve presente em 51 (15,4%) casos, sendo a comunicação interatrial a mais encontrada (27,4%), seguida de comunicação interventricular (25,4%) e anomalia de Ebstein (17,6%). Conclusão: Estudo eletrofisiológico e ablação com radiofrequência constituem ferramentas eficazes no diagnóstico e tratamento das arritmias na população pediátrica. .

Comparison of the pacemaker current in canine sino-atrial node cells and the wild type mHCN2 pacemaker current in neonatal rat myocardial cells / 中华老年医学杂志

Objective To investigate the dynamic characteristics of the pacemaker current of canine sino-atrial node cells and compare them with the wild type mHCN2 pacemaker current overexpressed in neonatal rat myocardial cells.Methods Fresh canine sino-atrial node cells were enzymatically isolated in a calcium-free solution containing collagenase and elastase,and the funny current was recorded and compared with the mHCN2 current overexpressed in cultured neonatal rat myocardial cells under the same experimental conditions.Results The canine sinus node cells were elongated,spindle-shaped or polygonal,with well-defined boundaries,and showed spontaneous beating.The elicited pacemaker current was an inward current and its rise in amplitude quickened as the hyperpolarization potential increased.At V ＝-75 mV,the canine sinus atrial node pacemaker current was (-2.1±0.3) pA/pF and had the same activation kinetics as those of the mHCN2 channel current overexpressed in neonatal rat myocardial cells [τact:(728±137) ms vs.(530±65) ms,P＞0.05].Conclusions Within the physiological range,the pacemaker current in canine sino-atrial node cells and the wild type mHCN2 pacemaker current over expressed in neonatal rat myocardial cells have similar activation kinetics.

Influence of long-term oral valsartan on ventricular arrhythmia after myocardial infarction in rabbits / 心血管康复医学杂志

Objective: To explore influence of long-term oral valsartan-angiotensin II type 1 receptor blocker on ventricular arrhythmia after myocardial infarction (MI) in rabbits and its possible mechanism. Methods: A total of 24 New Zealand rabbits were randomly divided into sham operation group (n=8), MI group (n=8) and valsartan group (n=8) according to number table. Sham operation group only received thoracotomy without ligation of anterior descending branch of left coronary artery (LAD), while MI group and valsartan group received ligation of anterior descending branch of LAD. Valsartan group received valsartan gavage (10 mg•kg-1•d-1) since the second day after operation, three groups all were fed for 12 weeks. Mono active potential (MAP) of left ventricular myocardial cells of subendocardial myocardium（inner layer myocardium）, subepicardial myocardium（outer layer myocardium）and middle layer myocardium were recorded before MI and 12 weeks after MI, and times of provocative malignant arrhythmias were recorded on 12 weeks after MI in three groups. Results: 1. Ventricular tachycardia or fibrillation (VT/ VF) episodes were markedly decreased in VAL group than that in MI group on 12 weeks after MI [(3.1±0.8) vs. (12.7±1.5), P＜0.05]; 2. After MI 12 w, the action potential duration to 90% repolarization (APD90) of three-layer ventricular myocytes in MI group was prolonged than that before MI [（259.2±22.1）ms,（288.0±25.8）ms,（244.6±22.6）ms vs.（230.1±23.2）ms,（244.2±23.4）ms,（229.0±21.7）ms, P＜0.05 or＜0.01]；but there were no significant difference in APD90 of three layers ventricular myocytes between before and after MI in valsartan group (P>0.05 all); Compared with sham operation group and valsartan group, there was significant prolonged in transmural dispersion of repolarization (TDR) [(18.8±6.2) vs. (23.9±7.7) vs. (37.2±10.2), P0.05). Conclusions: Long-term oral valsartan can significantly reduce malignant ventricular arrhythmia incidence in rabbits after MI, which may be related to improving TDR in rabbits after MI.

Exercise-Induced Intranodal Atrioventricular Block

Exercise-induced atrioventricular (AV) block in patients with normal AV conduction at rest is rare. Herein, we describe the case of a 67-year-old woman with normal 1 : 1 AV conduction at rest, who developed complete AV block during a treadmill test. Our patient complained of effort-related dizziness and dyspnea, which had been ongoing for 3 months. The patient's physical examination was normal. The resting electrocardiogram showed left anterior fascicular block with a PR interval of 0.19 seconds. The echocardiogram was normal except for mild aortic valve regurgitation. During the treadmill test, the patient developed complete AV block at a sinus rate of 90 beats/min, which was followed by 2 : 1 AV block associated with dyspnea and dizziness. The patient's coronary angiogram was normal, and the ergonovine provocation test was negative. Electrophysiological studies demonstrated rate-dependent intranodal AV block. The patient received implantation of a permanent dual chamber (DDD) pacemaker and had no further symptoms during the follow-up period.

Influence of Wenxin particle on cardiac electrophysiology in depressed rats after myocardial infarction / 心血管康复医学杂志

Objective: To investigate influence of Wenxin particle on cardiac electrophysiology in rats complicated with depression after myocardial infarction (MI). Methods: A total of 50 SD rats were randomly and equally divided into normal group, MI group, depression group, MI complicated with depression group (model group) and Wenxin particle group (Wenxin particle were given to model rats by gavage, 2 g/d, 28d). Model（MI complicated with depression）rats were made by acute ligation of left coronary artery and supply chronic unpredictable mild stress in order. The influences of Wenxin particle on cardiac electrophysiological indexes, such as monophasic action potential (MAP90), left ventricular effective refractory period (ERP) and ventricular fibrillation threshold (VFT) were evaluated in Wenxin particle group. Results: (1) Compared with normal group, there were significant decrease in behavior scores (P<0.05) in model group, after four-week treatment with Wenxin particle, their behavior scores significantly increased (P<0.01); (2) Compared with normal group, there were significant increase in MAPD90 and ERP, and significant decrease in VFT in model group (P<0.05); compared with model group, there were significant decrease in MAPD90 [(89.33±7.12) ms vs. (72.29±8.37) ms] and ERP [(84.00±6.57) ms vs. (68.00±7.43) ms], and significant increase in VFT [(7±3.11)V vs. (29±5.60)V] in Wenxin particle group, P<0.05. Conclusion: Wenxin particle can improve cardiac electrical remodeling in rats complicated with depression after myocardial infarction, including decrease monophasic action potential duration and effective refractory period, and raise ventricular fibrillation threshold.

Surgical cardiac synchronization therapy for the cardiomyopathy heart failure with micro-invasive thoracoscopy techniques / 中华胸心血管外科杂志

Objective The cardiac synchronization therapy (CRT) was proven to have good treatment for the cardiac conduction disorders patients with serious heart failure. But many disadvantages were gradually be noticed, such as difficulty of sinus electrode implantation, coronary sinus injury and bleeding, still one third CRT cases remain unchanged cardiac function.Recently the epicardial lead CRT therapy by the cardiac surgeons appears promising to provide better clinic resynchronization.The aim of this research is to explore the clinical value of surgical epicardial lead CRT for the cardiomyopathy heart failure with micro-invasive thoracoscopy techniques. Methods During April 2007 to Sep 2009 eleven patients were diagnosed as advanced heart failure with cardiac dysynchronization proven by the ECG and tissue Doppler echo examination. The dysynchronization parameters of tissue Doppler echo includes left ventricle maximize delay time , the left dysynchronization index (Ts-SD), the inter-ventricle mechanical delay time (IVMD), left ventricle end-dilation diameters (LVEDD) and the left ventricle ejection fraction (LVEF). All the patients got the consent agreement before the surgery. In the hybrid operation room the right atrial and ventricle endocardial electrodes were placed firs guided by X ray under the general anesthesia and double lumnen incubation. Then the thoracoscope techniques were used to explore the left ventricle lateral wall. The right atrial and ventricle electrodes were connected into the three chamber pacemaker. The Tissue Doppler Echo TEE technique was used to check which part of the left ventricle lateral wall is suitable for the idea CRT therapy. Usually the latest activated part of the left ventricle wall is the goal place. Then the epicardial electrode was fixed with 4-0 prolene suture at the idea place. All the cases were performed by the same surgeons group in the same medical center. The resynchronization features were examined after surgery and during the follow up. Results The endocardial and epicardial electrodes were implanted successfully without any serious complication. All patients were weaned and discharged without any adverse cardiac episodes. There is no mortality during the follow up period. All the patients received the β-blokers, diuretics, ACEI/ARB and other traditional medicine for the heart failure.The Tissue Doppler showed the E peak wave separated form the A peak which means the good resynchronization between the atrium and the ventricle. After surgery during the follow up the left ventricle maximize delay time decreased from (393.4 ±40.2 ) ms to ( 102.1 ± 34.6) ms, the left dysynchronization index (Ts-SD) decreased from (145.2±29.3)ms to(51.0±21.4) ms, the inter-ventricle mechanical delay time (IVMD) decreased from (59.1 ±23.4) ms to (31.2 ± 11.5 ) ms, left ventricle end-dilation diameters increased from (73.1 ± 13.4) mm to (63.2 ± 6.7) mn and the left ventricle ejection fraction increased from 0.32 ±0.04 to 0.41 ±0.07. Conclusion The micro-invasive surgical synchronization therapy could get good CRT result for the cardiomyopathy heart failure patients. Some patients traditionally in the waiting list for the heart transplant could be considered for the CRT therapy candidates.

Effects of hypothermia combined with sevoflurane on myocardial monophasic action potential and transmural dispersion of repolarization of ventricles in rabbits / 中华麻醉学杂志

Objective To investigate the effects of hypothermia combined with sevoflurane on myocardial monophasic action potential (MAP) and transmural dispersion of repolarization (TDR) of the left ventricle in rabbits in vitro. Methods Adult rabbits weighing 1.5-2.0 kg were sacrificed after heparinized and anesthetized.The hearts were immediately removed and perfused with K-H soluation saturated with 95%O2-5%CO2 at 37℃ in a Langendorff apparatus. Forty-eight isolated hearts were randomly divided into 6 groups ( n = 8 each): Ⅰ control group (group C), Ⅱ low concentration sevoflurane group ( group S1 ), Ⅲ high concentration sevoflurane group (group S2 ), Ⅳ hypothermia group (group H), Ⅴ hypothermia + low concentration sevoflurane (group HS1 ) and Ⅵ hypothermia + high concentraion sevoflurane (group HS2 ).Group C received continous perfusion. Group S1and S2 received perfusion with K-H solution saturated with 2.4% and 4.8% sevoflurane at 37 ℃ for 30 min respectively. Group H received perfusion with K-H solution at 30℃ for 30 min. Group HS1 and HS2 received perfusion with K-H solution saturated with 2.4% and 4.8% sevoflurane at 30℃ respectively.MAPs of epicardium, mid-myocardium and endocardium of the left ventricle were recorded. MAP duration at 90%repolarization(MAPD90)and TDR were calculated. Early after-depolarization,delayed after-depolarization and arrhythmia were also recorded. Results Compared with group C, MAPD90 of the 3 layers of ventricle was significandy prolonged, the incidence of arrhythmia increased in group H (P＜0.05). There was no significant difference in TDR among all groups ( P＞0.05). There was no interaction between sevoflurane and hypothermia (P＞0.05), and it only showed that MAPD90 was prolonged by hypothermia (P ＜0.05 ). Conclusion Hypothermia combined with sevoflurane exerts no significant effects on myocardial MAP and TDR of ventricles in rabbits, and sevoflurane decreases the incidence of hypothermia-induced arrhythmia through inhibiting the prolongation of MAPD90.

Influence of ablated cardiac fat pad on atrial fibrillation induced by a single extra-stimulus in dogs / 第二军医大学学报

Objective: To study the influence of ablated cardiac fat pad on atrial fibrillation induced by a single extra-stimulus in dogs. Metbods: Twenty-two dogs were anesthetized and their chest cavity was openned through a median sternotomy (2 dogs died of fibrillation immediately after opening) to expose the 3 cardiac fat pads: the medial superior vena cava and aortic root fat pad (SVC-Ao FP), the right pulmonary vein-atrial junction fat pad (RPV FP), and the inferior vena cava-left atrial junction fat pad (IVC-LA fat pad). The atrial effective refractory period (AERP), dispersion of AERP (dAERP), and pulmonary vein effective refractory period (PVERP) were measured under baseline and after ablation of the 3 fat pads. The left superior pulmonary veins were stimulated by S1S1 bursting stimulation and S1S2 program stimulation to induce atrial fibrillation before and after ablation. Results: After ablation, AERP increased from (137±16) ms to (147±16) ms and PVERP increased from (131±14) ms to (141+9) ms, while dAERP decreased from (17.0±4.6) ms to (12.0±4.3) ms (P<0.05). After ablation, S1S1 cycle length decreased from (173+25) ms to (145±21) ms when used for restimulation after ablation (P<0.05 ). S1S2 could not induce AF again. Conclusion: Ablation of the 3 cardiac fat pad can influence the electrical remodeling of the atrial and the pulmonary vein, which may hamper the induction of atrial fibrillation.

Electrophysiological effects of ibutilide on normal cardiac conduction system and accessory pathways / 第二军医大学学报

Objective: To observe the electrophysiological effects of ibutilide on the normal cardiac conduction system and accessory pathways (AP) of patients with accessory pathways mediated reentrant tachycardia (AVRT) and to assess the safety of ibutilide in electrophysiology study (EPS) and radiofrequency catheter ablation (RFCA). Methods: Twenty-one patients with AVRT undergoing EPS received intravenous ibutilide (1 mg). Electrophysiological parameters, including P-A interval, A-H interval, H-V interval, QRS complex width, QT interval, paced QT interval, right atrial effective refractory period (RA ERP), right ventricular ERP (RV ERP)q atrioventricular node ERP (AVN ERP), AVN block cycle length (AVN BCD, antegrade AP ERP and retrograde AP ERP 9 were observed before and instantly, 15 min, and 30 min after injection of ibutilide. Results: There was no statistical difference in the P-A interval, A-H interval, H-V interval and QRS complex width before and after ibutilide injection(P>0.05). After injection of ibutilide, the QTc, QT intervals, the RA ERP, RV ERP, and AVN BCL were all significantly prolonged (P<0.05). The antegrade and retrograde ERP of AP were also increased (P<0.05), with no loss of antegrade and retrograde function of AP. All patients underwent successful ablation and Torsade de pointes (Tdp) and no other adverse effects were noticed. Conclusion: Ibutilide has no effect on the conductivity of normal cardiac conduction system. Routine dosage of ibutilide can prolong ERP of AP but does not block the conductivity, with no influence on electrophysiology study and radiofrequency catheter ablation. Ibutilide has no adverse effect on patients with AVRT.

Comparative study of registration accuracy between 64-slice spiral CT and contrast enhanced MR in left atrium imaging for integrated cartography system / 中华放射学杂志

onclusions Both three-dimensional CT and MR images integrated into an CARTO system can be successfully used to perform catheter ablation for AF and there was no difference in registration accuracy between the two groups.

Age-associated electrophysiological changes of rat atrial muscle / 中华老年医学杂志

Objective To investigate the age-associated changes of electrophysiological properties of atrial muscle and the relationship between these changes and atrial fibrillation (AF). Methods According to their ages forty Wistar rats were divided into 4 age groups: young group, adult group, middle-aged group and old group (n=10 each group ). Hearts were isolated and perfused by Langendorff. MAP (monophasic action potential) of atrial muscle was recorded. MAPD (duration of MAP) and ERP (effective refractory period) at 400 ms of the stimulation cycle length, and MAPD at other different stimulation cycle lengths were measured in each group. Results At the stimulation cycle length of 400 ms, MAPD_(90) of right atrial muscle prolonged gradually from young group to old group (P

Circumferential pulmonary vein linear ablation for treating patients with recurrent atrial fibrillation / 中国介入心脏病学杂志

Objective To investigate the underlying mechanism for recurrence of atrial fibrillation (Afib) after trans- catheter ablation and the impact of repeat ablation on Afib. Methods Patients with symptomatic and ECG confirmed recurrent Afib were enrolled in this study. All patients underwent circumferential pulmonary vein linear ablation (CPVA) under the guidance of three dimension mapping system. The end-points of the procedure were electrical isolation of pulmonary vein (PVs)s and completeness of circumferential linear lesion around PVs. A systematic follow-up was conducted to evaluate the rate of atrial tachyarrhythmia free after the second ablation. Results Twenty-three cases (51.1% of the total recurrent cases of the same time) with recurrent Afib included in this study received second ablation. Among them, 13 cases underwent segmental PV ablation and the other 10 cases received CPVA. 56.5% (13/23) of the patients suffered from persistent and chronic Afib. Recovered conduction rate of PV-left atrium (LA) was 92.3% (48/52) in patients who had undergone SPVA during their first ablation and 75.0% (30/40) in patients who had received CPVA previously. Prolonged procedure time, more fluoroscopic exposure and higher radiofrequency needed were observed in patients who had undergone SPVA during their first ablation. 82.6% (19/23) of the patients were free from atrial tachy-arrhythmia during a mean follow-up of 4.2?3.5 (4.0～9.0) months after the second ablation. Conclusion Recovered conduction of PV-LA was the major factor responsible for the recurrence of Afib after the first procedure. CPVA under the guidance of three dimension mapping system may be feasiable for patient with recurrent atrial fibrilation.