Cardioversão elétrica em pacientes com fibrilação atrial e flutter atrial / Cardioversion electric in patients with atrial fibrillation and atrial flutter / Cardioversión eléctrica en pacientes con fabrilación atrial y flutter atrial

Objetivo: avaliar o posicionamento das pás-eletrodo do cardioversor durante realização de atendimento com cardioversão elétrica em pacientes com fibrilação atrial (FA) e flutter atrial (FlA). Método: estudo quantitativo, transversal, descritivo e analítico, de base documental, retrospectivo. Os dados foram coletados a partir dos prontuários dos pacientes, atendidos entre janeiro de 1999 e janeiro de 2006. Os dados foram analisados com uso dos testes de Mann-Whitney, qui-quadrado e Z. O projeto de pesquisa foi aprovado pelo Comitê de Ética em Pesquisa, protocolo n o . 689. Resultados: a amostra foi composta de 79 pacientes com FA e 33 com FlA. A resposta global à CVE foi de 91,1%. Na FA com abordagem anterolateral, a proporção de atendimentos com sucesso foi de 75% em contraponto com 94,9%, quando realizados com a abordagem anteroposterior. No FlA com abordagem anterolateral, o sucesso foi total, comparado ao índice de sucesso de 92,9% dos casos na abordagem anteroposterior. Nos pacientes com FA, o sucesso do choque inicial de 200J foi maior quando realizado na abordagem anteroposterior. Conclusão: nos casos de pacientes com FA, a CVE realizada na posição anteroposterior obteve sucesso superior à anterolateral.(AU)

Objective: to evaluate the positioning of the cardioverter blades electrode for performing service to electrical cardioversion in patients with atrial fibrillation (AF) and atrial flutter (AFL). Method: quantitative study, cross-sectional, descriptive and analytical retrospective documentary base. Data were collected from medical records of patients, treated between January 1999 and January 2006. Data were analyzed using the Mann-Whitney, chi-square and Z tests. The research project was approved by the Research Ethics Committee, under protocol number 689. Results: the sample consisted of 79 patients with AF and 33 with AFL. The global response to the ECV was 91.1%. In the AF anterolateral approach, the proportion of successful assistance was 75% as opposed to 94.9% when performed with antero-posterior approach. In the AFL with anterolateral approach, success was complete, compared to the success rate of 92.9% of cases in anteroposterior approach. In patients with AF, the success of the initial shock of 200J was higher when performed in the anteroposterior approach. Conclusion: in cases of patients with AF, ECV held in anteroposterior position, they obtained greater success to anterolateral.(AU)

Objetivo: evaluar la posición de las palas-electrodo del cardioversor durante realización de atendimiento con cardioversión eléctrica en pacientes con fibrilación atrial (FA) y flutter atrial (FlA). Método: estudio cuantitativo, de corte transversal, descriptivo y analítico de base documental retrospectivo. Los datos fueron recolectados a través de los prontuarios de los pacientes, atendidos entre enero de 1999 y enero de 2006. Los datos fueron analizados con uso de los tests de Mann-Whitney, chi-cuadrado y Z. El proyecto de investigación fue aprobado por el Comité de Ética en Investigación, sobre el protocolo n o . 689. Resultados: la muestra fue compuesta de 79 pacientes con FA y 33 con FlA. La respuesta global a la CVE fue de 91,1%. En la FA con enfoque antero lateral la proporción de atendimientos con suceso fue de 75% contra 94,9% cuando realizados con el enfoque anteroposterior. En FlA con enfoque antero lateral, el suceso fue total, comparado al índice de suceso de 92,9% de los casos en el enfoque anteroposterior. En los pacientes con FA, el suceso del choque inicial de 200J fue mayor cuando realizado en el enfoque anteroposterior. Conclusión: en los casos de pacientes con FA, CVE realizada en la posición anteroposterior obtuvo suceso superior a la antero lateral.(AU)

Effectiveness and costs of chemical versus electrical cardioversion of atrial fibrillation.

BACKGROUND: Atrial fibrillation is the most common sustained cardiac arrhythmia and has an important impact on costs of medical assistance. Traditional interventions to convert atrial fibrillation to sinus rhythm are antiarrhythmic drugs and external electrical cardioversion. However, the best option for starting the cardioversion is not well established. METHODS: In a multicentre randomised trial of 139 patients with persistent atrial fibrillation lasting less than 6 months, we compared the effectiveness and the cost-effectiveness ratio of initial treatment with chemical or electrical cardioversion. Subjects who did not achieve sinus rhythm with chemical cardioversion were considered to undergo electrical cardioversion and vice-versa. RESULTS: The efficacy of the initial attempt for cardioversion was similar with chemical or electrical cardioversion (74 vs. 73%, P=0.95). However, the strategy of starting with antiarrhythmic drugs was more effective than with electrical procedure (96 vs. 84%, P=0.0016). Initiating with chemical cardioversion was also less expensive than with electrical cardioversion (1240 US dollars vs. 1917 US dollars ; P=0.002). Life-threatening complications occurred only during chemical cardioversion (5%), all of them in patients with structural heart disease. CONCLUSIONS: In patients with persistent atrial fibrillation of less than 6 months, initial chemical or electrical cardioversion appear to be similar but the strategy of starting the cardioversion with antiarrhythmic drugs is more effective and less expensive than starting with the electrical procedure. Patients with structural heart disease undergoing chemical cardioversion seem to be more susceptible to severe complications.

Initial energy for external electrical cardioversion of atrial fibrillation.

OBJECTIVE: To investigate the initial energy level required for electrical cardioversion of atrial fibrillation (AF). METHODS: We studied patients undergoing electrical cardioversion in the 1st Multicenter Trial of SOCESP. Patients were divided into 2 groups according to the initial energy level of electrical cardioversion: 100J and >/=150J. We compared the efficacy of the initial and final shock of the procedure, the number of shocks administered, and the cumulative energy levels. RESULTS: Eight-six patients underwent electrical cardioversion. In 53 patients (62%), cardioversion was started with 100J, and in 33 patients (38%), cardioversion was started with >/=150J. Groups did not differ regarding clinical features and therapeutical interventions. A tendency existed towards greater efficacy of the initial shock in patients who received >/=150J (61% vs. 42% in the 100J group, p=0.08). The number of shocks was smaller in the >/=150J group (1.5+/-0.7 vs. 2.1+/-1.3, p=0.04). No difference existed regarding the final efficacy of electrical cardioversion and total cumulative energy levels in both groups. In the subgroup of patients with recent-onset AF (/=150J received fewer counter shocks with a tendency toward greater success than those patients who were given 100J; however, in patients with recent-onset AF, the average cumulative energy level was lower in the 100J group. These data suggest that electrical cardioversion should be initiated with energy levels >/=150J in patients with chronic AF.

Energia inicial para a cardioversäo elétrica externa da fibrilaçäo atrial / Initial energy for external electrical cardioversion of atrial fibrillation

OBJECTIVE - To investigate the initial energy level required for electrical cardioversion of atrial fibrillation (AF). METHODS - We studied patients undergoing electrical cardioversion in the 1st Multicenter Trial of SOCESP. Patients were divided into 2 groups according to the initial energy level of electrical cardioversion: 100J and > or = 150J. We compared the efficacy of the initial and final shock of the procedure, the number of shocks administered, and the cumulative energy levels. RESULTS - Eight-six patients underwent electrical cardioversion. In 53 patients (62 percent), cardioversion was started with 100J, and in 33 patients (38 percent), cardioversion was started with > or = 150J. Groups did not differ regarding clinical features and therapeutical interventions. A tendency existed towards greater efficacy of the initial shock in patients who received > or = 150J (61 percent vs. 42 percent in the 100J group, p=0.08). The number of shocks was smaller in the > or = 150J group (1.5±0.7 vs. 2.1±1.3, p=0.04). No difference existed regarding the final efficacy of electrical cardioversion and total cumulative energy levels in both groups. In the subgroup of patients with recent-onset AF (<=48h), the cumulative energy level was lower in the 100J group (240±227J vs. 324±225J, p=0.03). CONCLUSION - Patients who were given initial energy of > or = 150J received fewer counter shocks with a tendency toward greater success than those patients who were given 100J; however, in patients with recent-onset AF, the average cumulative energy level was lower in the 100J group. These data suggest that electrical cardioversion should be initiated with energy levels > or = 150J in patients with chronic AF

Useful clinical features for the selection of ideal patients with atrial fibrillation for mapping and catheter ablation.

OBJECTIVE: To identify useful clinical characteristics for selecting patients eligible for mapping and ablation of atrial fibrillation. METHODS: We studied 9 patients with atrial fibrillation, without structural heart disease, associated with: 1) antiarrhythmic drugs, 2) symptoms of low cardiac output, and 3) intention to treat. Seven patients had paroxysmal atrial fibrillation and 2 had recurrent atrial fibrillation. RESULTS: In the 6 patients who underwent mapping (all had paroxysmal atrial fibrillation), catheter ablation was successfully carried out in superior pulmonary veins in 5 patients (the first 3 in the left superior pulmonary vein and the last 2 in the right superior pulmonary vein). One patient experienced a recurrence of atrial fibrillation after 10 days. We observed that patients who had short episodes of atrial fibrillation on 24-hour Holter monitoring before the procedure were those in whom mapping the focus of tachycardia was possible. Tachycardia was successfully suppressed in 4 of 6 patients. The cause of failure was due to the impossibility of maintaining sinus rhythm long enough for efficient mapping. CONCLUSION: Patients experiencing short episodes of atrial fibrillation during 24-hour Holter monitoring were the most eligible for mapping and ablation, with a final success rate of 66%, versus the global success rate of 44%. Patients with persistent atrial fibrillation were not good candidates for focal ablation.

Características clínicas úteis para seleçäo do candidato ideal para mapeamento e ablaçäo de fibrilaçäo atrial / Useful clinical features for the selection of ideal patients with atrial fibrillation for mapping and catheter ablation

OBJECTIVE: To identify useful clinical characteristics for selecting patients eligible for mapping and ablation of atrial fibrillation. METHODS: We studied 9 patients with atrial fibrillation, without structural heart disease, associated with: 1) antiarrhythmic drugs, 2) symptoms of low cardiac output, and 3) intention to treat. Seven patients had paroxysmal atrial fibrillation and 2 had recurrent atrial fibrillation. RESULTS: In the 6 patients who underwent mapping (all had paroxysmal atrial fibrillation), catheter ablation was successfully carried out in superior pulmonary veins in 5 patients (the first 3 in the left superior pulmonary vein and the last 2 in the right superior pulmonary vein). One patient experienced a recurrence of atrial fibrillation after 10 days. We observed that patients who had short episodes of atrial fibrillation on 24-hour Holter monitoring before the procedure were those in whom mapping the focus of tachycardia was possible. Tachycardia was successfully suppressed in 4 of 6 patients. The cause of failure was due to the impossibility of maintaining sinus rhythm long enough for efficient mapping. CONCLUSION: Patients experiencing short episodes of atrial fibrillation during 24-hour Holter monitoring were the most eligible for mapping and ablation, with a final success rate of 66 percent, versus the global success rate of 44 percent. Patients with persistent atrial fibrillation were not good candidates for focal ablation

Fibrilação atrial / Atrial fibrillation

A fibrilaçäo atrial é a arritmia mais comum na prática cardiológica e se associa a elevados índices de morbidade, principalmente relacionados aos eventos embólicos. O tratamento dessa entidade clínica depende de diversos fatores, como sintomas, duraçäo das crises e cardiopatia de base, observando-se taxas elevadas de até 50 "por cento" de recorrências em um ano com o tratamento antiarrítmico. O tratamento consiste na reversäo da arritmia por meio de cardioversäo elétrica ou medicamentosa na fase aguda, e na prevençäo das recorréncias na fase de manutençäo. Na impossibilidade de reversäo para o ritmo sinusal, o tratamento deve objetivar o controle farmacológico da frequência ventricular e a prevençäo dos fenômenos tromboembólicos. A modulaçä da conduçäo nodal e a ablaçäo da junçäo atrioventricular por meio de cateteres, utilizando-se radiofrequência como fonte de energia, podem ser indicados nos casos onde o controle farmacológicos foi ineficaz. Estudos iniciais apontam para um futuro promissor na ablaçäo cirúrgica ou por cateteres da fibrilaçäo atrial.

Projeções preferenciais para mapeamento e ablação da taquicardia de via de saída do ventrículo direito. Estudo anátomo-radiológico / Preferential projections for mapping and ablation of right ventricular outflow tract tachycardica. an anatomo-radiologic Study

PURPOSE--To select ideal radiologic projections for mapping and ablation of tachycardias of right ventricular outflow tract (RVOT). METHODS--Ten hearts from human corpses were studied utilizing radiopaque material to identify the pulmonary valve and three distinct sites on this valve: septal anterior (A), septal posterior (P) and free-wall (L). Next, the hearts were filmed in the frontal plane and in oblique projections with 15 degrees increments to the right and to the left. The projections in which the sites were lateralized on the valve, eased radiologic interpretation and were considered ideal for mapping and ablation. Depending on the proximity of the sites to the lateral extremes of the pulmonary valve, the projections were considered ideal ( ), intermediary (++) and inadequate (+). RESULTS--Projections [table: see text] CONCLUSION--The A site of RVOT was best indicated in the 60 and 45 degrees left anterior oblique projections; the 0 degree postero anterior projection was best for mapping the P site; the L region was best explored in the 60 degrees right anterior oblique projection.

Objetivo - Identificar projeções ideais para mapeamento e ablação de taquicardias da via de saída do ventrículo direito (VSVD) através de estudo anátomo-radioscópico detalhado em corações de cadáveres. Métodos - Dez corações de cadáveres humanos foram estudados, utilizando-se material radiopaco para demarcar o anel pulmonar e três regiões distintas neste anel: septal anterior (A), septal posterior (P) e parede livre (L). Em seguida, foi realizada cine-radioscopia no plano frontal e em projeções oblíquas, com incrementos progressivos para a direita e para a esquerda. As projeções nas quais as regiões demarcadas ficaram mais lateralizadas, facilitavam a interpretação radiológica e foram as consideradas ideais para mapeamento e ablação. Dependendo da proximidade das regiões demarcadas com as extremidades laterais do anel pulmonar, as projeções foram consideradas ótimas (+++), intermediárias (++) e inadequadas (+). Resultados - Conclusão - A região A da VSVD foi melhor indicada nas projeções oblíqua anterior esquerda a 600 e 45°; a projeçãopóstero-anterior a 0° foi mais adequada para mapear a região P; a região L foi melhor explorada em projeção oblíqua anterior direita a 60º.

Análise das características do ritmo juncional em pacientes com taquicardia por reentrada nodal submetidos a ablação da via lenta por radiofreqüência / Characteristics of Junctional Rhythm During Radiofrequency Catheter Ablation of Slow Pathway in Atrioventricular Nodal Reentrant Tachycardia

PURPOSE--To study the quantitative and qualitative aspects of junctional rhythm (JR) during radiofrequency (RF) catheter ablation of slow pathway in atrioventricular nodal reentrant tachycardia. METHODS--Twenty five patients, 5 males, ages ranging from 15 to 76 years, with recurrent atrioventricular nodal reentrant tachycardia, underwent to RF catheter ablation of slow pathway. During RF applications (40V, duration 60s) electrocardiographic was continuously recorded. The recordings were posteriorly used to study the presence and characteristics of JR (number of episodes, frequency and time of onset) at the effective and ineffective RF sessions. All variables were expressed as median and mean +/- SD. Univariate analysis of the effects of each variable on success or failure of ablation were performed using x2 test. A p value < 0.05 was considered significant. RESULTS--One hundred forty nine RF sessions were performed, 25 effective and 124 ineffective (mean per patient 6, range 1 to 22). JR was present in 18 of 25 effective and 44 of 124 ineffective sessions (p < 0.05). Mean time of appearance was 12s, occurring later this time in 9 of 18 effective and in 10 of 44 ineffective sessions (p < 0.05). Mean number of episodes was 3, occurring higher number in 7 of 18 effective and in 4 of 44 ineffective sessions (p < 0.05). Median of frequency of JR was 100bpm; 11 of 18 effective and 15 of 44 ineffective sessions presented higher frequencies (p < 0.05). CONCLUSION--JR during slow pathway ablation is a sensitive marker of ablation success. JR predictor of success has higher number of episodes, higher frequency and later time of appearance than that one of ineffective sessions.

Objetivo - Estudar quantitativa e qualitativamente as características do ritmo juncional (RJ) ocorrido durante o procedimento de ablação por cateter da via lenta, em pacientes com taquicardia por reentrada nodal. Métodos - Vinte e cinco pacientes (5 homens, 15 a 76 anos) foram submetidos a ablação por cateter da via lenta, utilizando radiofreqüência (RF). Durante as sessões de RF de 40V, com 1min de duração, foi realizado o registro eletrocardiográfico contínuo, na velocidade de 25mm/s. Os registros serviram, posteriormente, para análise da presença e das características do RJ (número de episódios, freqüência e tempo de aparecimento após o início da RF), nas sessões eficazes e ineficazes. As variáveis estudadas foram expressas em mediana, média e desvio-padrão. A análise univariada do efeito das mesmas no sucesso da ablação foi realizada, utilizando-se o teste do qui-quadrado. Valor de p<0,05 foi considerado significante. Resultados - Foram realizadas 149 sessões de RF (média de 6/paciente, variando de 1 a 22), sendo 25 eficazes e 124 ineficazes. O RJ esteve presente em 18 de 25 sessões eficazes e em 44 de 124 ineficazes (p<0,05). A média do tempo de aparecimento do RJ após o início da RF foi de 12s, aparecendo em tempo superior à média em 9 de 18 sessões eficazes e em 10 de 44 ineficazes (p<0,05). A média do número de episódios de RJ foi 3, sendo maior que a média em 7 de 18 sessões eficazes e em 4 de 44 ineficazes (p<0,05). A mediana da freqüência do RJ foi de 100bpm, sendo maior que esse valor em 11 de 18 sessões eficazes e em 15 de 44 ineficazes (p<0,05). Conclusão - O RJ durante ablação com RF é um marcador sensível do sucesso do procedimento. O RJ preditor de sucesso apresenta número maior de episódios, freqüência cardíaca mais elevada e aparece mais tardiamente durante o pulso de RF, quando comparado ao que resulta ineficaz