Teste de Limiar de Desfibrilação e Seguimento a Longo Prazo de Pacientes com Cardiopatia Crônica da Doença de Chagas / Defibrillation Threshold Testing and Long-term Follow-up in Chagas Disease

Resumo Fundamento A morte súbita cardíaca (MSC) é a causa mais comum de óbito na cardiomiopatia crônica da doença de Chagas (CCDC). Visto que muitos pacientes com CCDC que são candidatos a receber um cardioversor desfibrilador implantável (CDI) atendem a critérios que sugerem alto risco de apresentarem limiares de desfibrilação elevados, sugere-se realizar um teste de limite de desfibrilação (LDF). Objetivos Investigamos o uso do teste de LDF em pacientes com CCDC, com enfoque nos óbitos relacionados ao implante do CDI e na ocorrência de eventos arrítmicos e o tratamento oferecido durante o seguimento de longo prazo. Métodos Avaliações retrospectivas de 133 pacientes com CCDC que receberam CDI, principalmente para prevenção secundária. Foram coletados dados demográficos, clínicos e laboratoriais, escore de Rassi e dados do teste de LDF. Adotou-se p<0,05 como estatisticamente significativo. Resultados A média de idade foi 61±13 anos, e 72% da amostra era do sexo masculino. A fração de ejeção basal do ventrículo esquerdo foi 40±15%, e o escore de Rassi médio foi 10±4 pontos. Não ocorreram óbitos durante o teste de LDF, e não foram documentadas falhas do CDI. Foi identificada relação entre escore de Rassi basal mais elevado e LDFs mais elevados (ANOVA =0,007). O tempo médio até o primeiro choque foi de 474±628 dias, mas a aplicação de choque foi necessária em apenas 28 (35%) pacientes com TV, visto que a maioria dos casos se resolveu espontaneamente ou através da programação de ATP. Após seguimento clínico de 1728±1189 dias, em média, ocorreram 43 óbitos, relacionados principalmente a insuficiência cardíaca progressiva e sepse. Conclusões Um teste de LDF de rotina pode não ser necessário para pacientes com CCDCs que receberam CDI para prevenção secundária. LDFs elevados parecem ser incomuns e podem estar relacionados a escore de Rassi elevado.

Abstract Background Sudden cardiac death is the most common cause of death in chronic Chagas cardiomyopathy (CCC). Because most CCC patients who are candidates for implantable cardioverter-defibrillators (ICD) meet criteria for high defibrillation threshold values, a defibrillator threshold test (DTT) is suggested. Objectives We investigated the use of DTT in CCC patients, focusing on deaths related to ICD and arrhythmic events, as well as treatment during long-term follow-up. Methods We retrospectively evaluated 133 CCC patients who received an ICD mainly for secondary prevention. Demographic, clinical, laboratory data, Rassi score, and DTT data were collected, with p < 0.05 considered significant. Results The mean patient age was 61 (SD, 13) years and 72% were men. The baseline left ventricular ejection fraction was 40 (SD, 15%) and the mean Rassi score was 10 (SD, 4). No deaths occurred during DTT and no ICD failures were documented. There was a relationship between higher baseline Rassi scores and higher DTT scores (ANOVA = 0.007). The mean time to first shock was 474 (SD, 628) days, although shock was only necessary for 28 (35%) patients with ventricular tachycardia, since most cases resolved spontaneously or through antitachycardia pacing. After a mean clinical follow-up of 1728 (SD, 1189) days, 43 deaths occurred, mainly related to progressive heart failure and sepsis. Conclusions A routine DTT may not be necessary for CCC patients who receive an ICD for secondary prevention. High DTT values seem to be unusual and may be related to high Rassi scores.

Defibrillation Threshold Testing and Long-term Follow-up in Chagas Disease. / Teste de Limiar de Desfibrilação e Seguimento a Longo Prazo de Pacientes com Cardiopatia Crônica da Doença de Chagas.

BACKGROUND: Sudden cardiac death is the most common cause of death in chronic Chagas cardiomyopathy (CCC). Because most CCC patients who are candidates for implantable cardioverter-defibrillators (ICD) meet criteria for high defibrillation threshold values, a defibrillator threshold test (DTT) is suggested. OBJECTIVES: We investigated the use of DTT in CCC patients, focusing on deaths related to ICD and arrhythmic events, as well as treatment during long-term follow-up. METHODS: We retrospectively evaluated 133 CCC patients who received an ICD mainly for secondary prevention. Demographic, clinical, laboratory data, Rassi score, and DTT data were collected, with p < 0.05 considered significant. RESULTS: The mean patient age was 61 (SD, 13) years and 72% were men. The baseline left ventricular ejection fraction was 40 (SD, 15%) and the mean Rassi score was 10 (SD, 4). No deaths occurred during DTT and no ICD failures were documented. There was a relationship between higher baseline Rassi scores and higher DTT scores (ANOVA = 0.007). The mean time to first shock was 474 (SD, 628) days, although shock was only necessary for 28 (35%) patients with ventricular tachycardia, since most cases resolved spontaneously or through antitachycardia pacing. After a mean clinical follow-up of 1728 (SD, 1189) days, 43 deaths occurred, mainly related to progressive heart failure and sepsis. CONCLUSIONS: A routine DTT may not be necessary for CCC patients who receive an ICD for secondary prevention. High DTT values seem to be unusual and may be related to high Rassi scores.

FUNDAMENTO: A morte súbita cardíaca (MSC) é a causa mais comum de óbito na cardiomiopatia crônica da doença de Chagas (CCDC). Visto que muitos pacientes com CCDC que são candidatos a receber um cardioversor desfibrilador implantável (CDI) atendem a critérios que sugerem alto risco de apresentarem limiares de desfibrilação elevados, sugere-se realizar um teste de limite de desfibrilação (LDF). OBJETIVOS: Investigamos o uso do teste de LDF em pacientes com CCDC, com enfoque nos óbitos relacionados ao implante do CDI e na ocorrência de eventos arrítmicos e o tratamento oferecido durante o seguimento de longo prazo. MÉTODOS: Avaliações retrospectivas de 133 pacientes com CCDC que receberam CDI, principalmente para prevenção secundária. Foram coletados dados demográficos, clínicos e laboratoriais, escore de Rassi e dados do teste de LDF. Adotou-se p<0,05 como estatisticamente significativo. RESULTADOS: A média de idade foi 61±13 anos, e 72% da amostra era do sexo masculino. A fração de ejeção basal do ventrículo esquerdo foi 40±15%, e o escore de Rassi médio foi 10±4 pontos. Não ocorreram óbitos durante o teste de LDF, e não foram documentadas falhas do CDI. Foi identificada relação entre escore de Rassi basal mais elevado e LDFs mais elevados (ANOVA =0,007). O tempo médio até o primeiro choque foi de 474±628 dias, mas a aplicação de choque foi necessária em apenas 28 (35%) pacientes com TV, visto que a maioria dos casos se resolveu espontaneamente ou através da programação de ATP. Após seguimento clínico de 1728±1189 dias, em média, ocorreram 43 óbitos, relacionados principalmente a insuficiência cardíaca progressiva e sepse. CONCLUSÕES: Um teste de LDF de rotina pode não ser necessário para pacientes com CCDCs que receberam CDI para prevenção secundária. LDFs elevados parecem ser incomuns e podem estar relacionados a escore de Rassi elevado.

Recomendações para o manejo de dispositivos cardíacos eletrônicos implantáveis post mortem / Recommendations for the post-mortem management of cardiac implantable electronic devices

O manejo de dispositivos cardíacos eletrônicos implantáveis de pacientes que evoluem a óbito tem sido motivo de controvérsia. Em nosso meio, não há recomendações uniformes, estando baseadas exclusivamente em protocolos institucionais e em costumes regionais. Quando o cadáver é submetido para cremação, além de outros cuidados, recomenda-se a retirada do dispositivo devido ao risco de explosão e dano do equipamento crematório. Principalmente no contexto da pandemia causada pelo SARS-Cov-2, a orientação e organização de unidades hospitalares e serviços funerários é imprescindível para minimizar o fluxo de pessoas em contato com fluidos corporais de indivíduos falecidos por COVID-19. Nesse sentido, a Sociedade Brasileira de Arritmias Cardíacas elaborou este documento com orientações práticas, tendo como base publicações internacionais e recomendação emitida pelo Conselho Federal de Medicina do Brasil.

The management of cardiac implantable electronic devices after death has become a source of controversy. There are no uniform recommendations for such management in Brazil; practices rely exclusively on institutional protocols and regional custom. When the cadaver is sent for cremation, it is recommended to remove the device due to the risk of explosion and damage to crematorium equipment, in addition to other precautions. Especially in the context of the SARS-CoV-2 pandemic, proper guidance and organization of hospital mortuary facilities and funeral services is essential to minimize the flow of people in contact with bodily fluids from individuals who have died with COVID-19. In this context, the Brazilian Society of Cardiac Arrhythmias has prepared this document with practical guidelines, based on international publications and a recommendation issued by the Brazilian Federal Medical Council.

Electrical Storm in Chagas Cardiomyopathy: Clinical Predictors, Outcome, and Arrhythmic Characteristics in a Prospective Registry.

OBJECTIVES: This study of patients with Chagas heart disease (CHD) with an implantable cardioverter-defibrillator (ICD) for secondary prevention of sudden cardiac death sought to compare the characteristics of those with or without electrical storm (ES) during long-term follow-up. BACKGROUND: ES is a common problem in patients with CHD harboring an ICD, but data on clinical predictors and outcomes are limited. METHODS: The authors retrospectively evaluated 110 patients with CHD with a mean follow-up of 1,949 ± 1,271 days. Demographic, clinical, arrhythmia characteristics, ICD treatment, and death data were collected. Descriptive statistics included mean ± SD and Fisher exact tests used for comparisons. A p value <0.05 was considered significant. RESULTS: The ES group (n = 57; 43 men; age 62 ± 10 years) and the non-ES group (n = 53; 43 men; age 57 ± 14 years) had similar baseline demographic and clinical parameters, but left ventricular ejection fraction was higher in the ES group (44 ± 14% vs. 37 ± 14%; p = 0.02) and QRS duration was shorter (109 ± 35 ms vs. 134 ± 36 ms; p = 0.0027). Mortality rates were comparable in the 2 groups (odds ratio: 1.2; 95% confidence interval: 0.79 to 1.85; p = 0.44). The ES group presented 116 ES (2.03 ±1.47, 1 to 6). A total of 2,953 (61%) arrhythmic events required ICD therapy. No deaths occurred directly caused by ES, but clinical triggers were reported in 20 patients. CONCLUSIONS: ES is frequent in CHD but in itself does not carry a worse prognosis in this study population and was not associated with a more depressed left ventricular systolic function or a longer QRS.

Recommendations for the Post-Mortem Management of Cardiac Implantable Electronic Devices. / Recomendações para o Manejo de Dispositivos Cardíacos Eletrônicos Implantáveis Post Mortem.

The management of cardiac implantable electronic devices after death has become a source of controversy. There are no uniform recommendations for such management in Brazil; practices rely exclusively on institutional protocols and regional custom. When the cadaver is sent for cremation, it is recommended to remove the device due to the risk of explosion and damage to crematorium equipment, in addition to other precautions. Especially in the context of the SARS-CoV-2 pandemic, proper guidance and organization of hospital mortuary facilities and funeral services is essential to minimize the flow of people in contact with bodily fluids from individuals who have died with COVID-19. In this context, the Brazilian Society of Cardiac Arrhythmias has prepared this document with practical guidelines, based on international publications and a recommendation issued by the Brazilian Federal Medical Council.

O manejo de dispositivos cardíacos eletrônicos implantáveis de pacientes que evoluem a óbito tem sido motivo de controvérsia. Em nosso meio, não há recomendações uniformes, estando baseadas exclusivamente em protocolos institucionais e em costumes regionais. Quando o cadáver é submetido para cremação, além de outros cuidados, recomenda-se a retirada do dispositivo devido ao risco de explosão e dano do equipamento crematório. Principalmente no contexto da pandemia causada pelo SARS-Cov-2, a orientação e organização de unidades hospitalares e serviços funerários é imprescindível para minimizar o fluxo de pessoas em contato com fluidos corporais de indivíduos falecidos por COVID-19. Nesse sentido, a Sociedade Brasileira de Arritmias Cardíacas elaborou este documento com orientações práticas, tendo como base publicações internacionais e recomendação emitida pelo Conselho Federal de Medicina do Brasil.

Recomendações para o manejo de dispositivos cardíacos eletrônicos implantáveis post mortem / Recommendations for the post-mortem management of cardiac implantable electronic devices

Resumo O manejo de dispositivos cardíacos eletrônicos implantáveis de pacientes que evoluem a óbito tem sido motivo de controvérsia. Em nosso meio, não há recomendações uniformes, estando baseadas exclusivamente em protocolos institucionais e em costumes regionais. Quando o cadáver é submetido para cremação, além de outros cuidados, recomenda-se a retirada do dispositivo devido ao risco de explosão e dano do equipamento crematório. Principalmente no contexto da pandemia causada pelo SARS-Cov-2, a orientação e organização de unidades hospitalares e serviços funerários é imprescindível para minimizar o fluxo de pessoas em contato com fluidos corporais de indivíduos falecidos por COVID-19. Nesse sentido, a Sociedade Brasileira de Arritmias Cardíacas elaborou este documento com orientações práticas, tendo como base publicações internacionais e recomendação emitida pelo Conselho Federal de Medicina do Brasil.

Morte súbita em Doença de Chagas ­conceitos atuais e perspectivas de novos avanços / Sudden cardiac death in Chagas Heart Disease- current concepts and perspectives for new advances

A Doença de Chagas atinge milhões de pessoas na América Latina e a evolução para cardiopatia crônica tem como seu principal desfecho a morte súbita cardíaca (MSC). Neste artigo, revisamos, sob a luz da medicina baseada em evidências, os principais aspectos sobre marcadores prognósticos clínicos e de imagem (especificamente a análise da fibrose em ressonância magnética) e terapêutica existente no tratamento e prevenção da MSC, como terapia farmacológica, evidências sobre dispositivos implantáveis e tratamento invasivo de arritmias ventriculares

Chagas disease affects millions of people in Latin America and its evolution to heart disease has the sudden cardiac death (SCD) as one main outcome. In this article, we sought to review the essential evidence-based aspects about prognostic markers and treatments for SCD, including farmacological treatment, use of implantable devices and invasive treatment of ventricular arrhthymias

Long-term follow-up of Chagas heart disease patients receiving an implantable cardioverter-defibrillator for secondary prevention.

BACKGROUND: Chagas heart disease (CHD) is a dilated cardiomyopathy characterized by malignant ventricular arrhythmias and increased risk of sudden cardiac death (SCD). Much controversy exists concerning the efficacy of implantable cardioverter-defibrillator (ICDs) in CHD because of mixed results observed. We report our long-term experience with ICDs for secondary prevention in CHD, with the specific aim of assessing the results in groups with preserved or depressed global left ventricular function. METHODS: 111 patients (75 males; 60 ± 12 years) were followed for 1,948 ± 1,275 days after ICD. Time to death was the primary outcome; LVEF ≤ 45% the exposure; and age, gender, and ICD therapy delivery the potential confounders. We used time-to-event methods and Cox proportional models for analysis, censoring observations at time of death or at 5-year follow-up in survivors. RESULTS: Seventy-two percent of the patients presented at least one sustained ventricular arrhythmia requiring appropriate therapy, and only three patients received inappropriate therapy. Death occurred in 50 (45%) patients, with an annual mortality rate of 8.4%, mostly due to refractory heart failure or noncardiac causes. Unadjusted survival rates were significantly distinct between patients with left ventricular ejection fraction (LVEF) ≤ 45% (26 deaths), 50.5% (95% confidence interval [CI]: 36.2%-63.2%) when compared to patients with LVEF > 45% (10 deaths), 77.6% (95% CI: 62.3%-87.3%, P < 0.01). After adjusting for confounders, low LVEF (hazard ratio [HR]: 5.2, 95% CI: 2.3-11.6), age (HR: 1.04, 95% CI: 1.01-1.07), and female gender (HR: 3.97, 95% CI: 1.85-8.54) were independently associated with the outcome. CONCLUSIONS: ICDs successfully aborted life-threatening arrhythmias in CHD patients. Impaired left ventricular function predicted higher mortality in CHD patients with an ICD for secondary prevention of SCD.

Abordagem e investigação clínica em pacientes com taquicardia ventricular sustentada / Approach and clinical research in patients with sustained ventricular tachycardia

A taquicardia ventricular sustentada (TVS) é uma emergência clínica em que há risco de mortalidade súbita cardíaca, daí a necessidade de ser abordada de modo objetivo e sistemático. História clínica, exame físico e ECG são fundamentais na abordagem do paciente com taquicardia de QRS largo. Devem ser pesquisados ativamente os preditores clínicos, sinais clínicos e critérios eletrocardiográficos capazes de diagnosticar com grande probabilidade de acerto a TVS. Após a abordagem de emergência, o paciente deve ser encaminhado para avaliação da cardiopatia. Os testes diagnósticos incluem métodos gráficos (ECG basal, teste de esforço, ECGAR e eletrocardiografia dinâmica) e de imagem (ecocardiograma, ressonância magnética e tomografia computadorizada). Há ainda a possibilidade de avaliação invasiva (estudo eletrofisiológico). Apresenta-se uma revisão das estretégicas de abordagem de pacientes com taquicardia ventricular e dos métodos diagnósticos que auxiliam a busca da cardiopatia subjacente.

Impact of corticosteroids on late growth of radiofrequency lesions in infant pigs: histopathological and electroanatomical findings.

AIMS: Corticosteroids attenuate late growth of radiofrequency (RF) lesions in the thigh muscle of infant rats. We sought to assess the impact of these drugs on the late growth of RF lesions in immature swine myocardium and to determine the electroanatomical mapping (EAM) characteristics of these lesions. METHODS AND RESULTS: Radiofrequency (60°C; 60 s) lesions were created in the right atrium (n = 2) and ventricle (n = 2) of 14 piglets (age 65 days; weight 5 kg) and 3 adults. Piglets were divided into: controls (n = 7) and treated (n = 7), receiving hydrocortisone (10 mg/kg iv after RF) and prednisone (1 mg/kg/day) for 29 days. After 8 months, animals were sacrificed for histological analysis. In four piglets, endocardial and epicardial voltage EAM were performed. In infant groups, the dimensions of atrial (11 ± 5 vs. 13 ± 7 mm) and ventricular (12 ± 3 vs. 11 ± 3 mm) lesions were similar. In adults, atrial (6 ± 1 mm) and ventricular (6 ± 1 mm) lesions were smaller. In controls, ventricular lesions depicted dense fibrosis and multiple strands of fibrous tissue extending from the lesion into normal muscle. Treated piglets revealed scars exhibiting less dense fibrosis with predominance of fibroadipose tissue and less collagen proliferation. Large atrial and ventricular low-voltage areas corresponding to the macroscopic lesions were identified in all animals. CONCLUSION: Radiofrequency lesions in infant pigs reveal late growth and invasion of normal muscle by intense collagen proliferation. Corticosteroids do not prevent late enlargement of the lesions but modulate the fibrotic proliferation. The expressive growth of the lesion may generate low-voltage areas detectable by EAM.

Avanços no tratamento farmacológico da fibrilação atrial / Advances in the pharmacological treatment of atrial fibrillation

A fibrilação atrial é a arritmia sustentada mais comum na prática clínica, com aumento expressivo da prevalência a partir da sexta década de vida. Proporcionalmente ao envelhecimento da população, há perspectivas de estatísticas ainda mais preocupantes dessa entidade em alguns anos. Drogas antiarrítmicas são ferramentas essenciais na tentativa da manutenção do ritmo sinusal. Se houver recorrência da fibrilação atrial, estratégia de manejo com controle de frequência cardíaca também pode ser adotada. Sem intervenções mais efetivas, a morbidade e a mortalidade cardiovascular e cerebrovascular relacionadas à fibrilação atrial vão continuar crescendo. Embora haja na atualidade significativa expansão no uso de ablação com resultados cada vez mais promissores, a técnica poderá não ser apropriada em todos os casos e a terapia farmacológica continuará exercendo importante papel no manejo dessa arritmia. Nenhuma das drogas antiarrítmicas disponíveis é totalmente satisfatória, cada uma tendo eficácia limitada combinada com segurança e tolerabilidade restritas. Fármacos análogos da amiodarona (dronedarona), novas classes de antiarrítmicos (como agentes atriais seletivos) e terapia adjuvantes, que lidam com substrato, representam fontes potenciais de novas terapias farmacológicas para fibrilação atrial.

Atrial fibrillation is the most common sustained arrhythmia in the clinical practice, and its prevalence increases significantly in individuals over 60 years of age. As the population grows older, the statistical perspectives tend to get even worse. Antiarrhythmic drugs are essential tools to maintain sinus rhythm. In case of atrial fibrillation recurrences, heart rate control strategies may also be adopted. Without effective interventions, cardiovascular and cerebrovascular morbidity and mortality due to atrial fibrillation will continue to grow. Although there has been a significant increase in the use of ablation with promising results, the technique might not be appropriate for all of the cases and pharmacological therapy will continue to play an important role in the management of this arrhythmia. None of the currently available antiarrhythmic drugs are completely satisfactory, each one of them have efficacy, safety and tolerability limitations. Amiodarone analogs (dronedarone), new classes of antiarrhythmics (such as selective atrial agents) and adjuvant therapies with substrate, constitute potential pharmacological approaches for atrial fibrillation.

Characterization of the acute cardiac electrophysiologic effects of ethanol in dogs.

BACKGROUND: Alcohol has been related to atrial fibrillation (holiday heart syndrome), but its electrophysiologic actions remain unclear. METHODS: We evaluated the effects of alcohol in 23 anesthetized dogs at baseline and after 2 cumulative intravenous doses of ethanol: first dose 1.5 ml/kg (plasma level 200 mg/dl); second dose 1.0 ml/kg (279 mg/dl). In 13 closed-chest dogs (5 with intact autonomic nervous system, 5 under combined autonomic blockade and 3 sham controls), electrophysiologic evaluation and monophasic action potential (MAP) recordings were undertaken in the right atrium and ventricle. In 5 additional dogs, open-chest biatrial epicardial mapping with 8 bipoles on Bachmann's bundle was undertaken. In the remaining 5 dogs, 2D echocardiograms and ultrastructural analysis were performed. RESULTS: In closed-chest dogs with intact autonomic nervous system, ethanol had no effects on surface electrocardiogram and intracardiac variables. At a cycle length of 300 milliseconds, no effects were noted on atrial and ventricular refractoriness and on the right atrial MAP. These results were not altered by autonomic blockade. No changes occurred in sham controls. In open-chest dogs, ethanol did not affect inter-atrial conduction time, conduction velocity, and wavelength. Atrial arrhythmias were not induced in any dog, either at baseline or after ethanol. Histological and ultrastructural findings were normal but left ventricular (LV) ejection fraction decreased in treated dogs (77 vs. 73 vs. 66%; p = 0.04). CONCLUSION: Ethanol at medium and high doses depresses LV systolic function but has no effects on atrial electrophysiological parameters. These findings suggest that acute alcoholic intoxication does not directly promote atrial arrhythmias.

Acute and chronic effects of extensive radiofrequency lesions in the canine caval veins: implications for ablation of atrial arrhythmias.

BACKGROUND: Although radiofrequency (RF) ablation within the caval veins has been increasingly used to treat a variety of atrial tachyarrhythmias, the consequences of RF ablation in the caval veins are unknown. We explored the acute and chronic angiographic and pathological effects of extensive RF ablation in the caval veins. METHODS: Under fluoroscopy guidance, conventional (4 mm tip, 60 degrees C, 60 seconds) RF applications (n = 6-7) were delivered in each vena cava (from +/-2 cm into the vein to the veno-atrial junction) of 15 dogs (10 +/- 3 kg). Animals were killed 1 hour and 5 weeks after ablation for histological analysis. Angiography was performed before ablation (acute dogs only) and at sacrifice to assess the degree of vascular stenosis. RESULTS: In acute dogs (n = 5), luminal narrowing was noted in 10/10 (100%) targeted veins (mild in two; moderate in three and severe in five, including two total occlusions). In the six chronic animals that completed the protocol (four died during follow-up), stenosis was also observed in 12/12 (100%) ablated veins (mild in six; moderate in four and severe in two). Of these, one superior vena cava was suboccluded with development of extensive collateral circulation. Histologically, acute lesions displayed typical transmural coagulative necrosis, whereas chronic lesions revealed intimal proliferation, necrotic muscle replaced with collagen, endovascular contraction, and disruption and thickening of the internal elastic lamina. CONCLUSION: In this model, extensive RF ablation in the caval veins may result in significant vascular stenosis. These findings may have implications for catheter ablation of arrhythmias originating within the caval veins.

Arritmias na insuficiência cardíaca / Arrhythmias in heart failure

As arritmias freqüentemente complicam o manuseio da insuficiência cardíaca e contribuem para o aumento de sua morbidade e mortalidade. A incidência de fibrilação atrial aumenta proporcionalmente à gravidade da insuficiência cardíaca. A anticoagulação e o controle da freqüência cardíaca são importantes, e a estratégia de manutenção do ritmo sinusal ainda não se mostrou superior à do controle da freqüência. O implante dos cardioversores-desfibriladores-implantáveis constitui atualmente a forma mais efetiva de prevenção contra a morte súbita; porém, provavelmente, seu benefício é inferior nos portadores de insuficiência cardíaca em relação à população dos estudos com desfibriladores. A amiodarona é a opção farmacológica mais importante para o tratamento de arritmias sintomáticas nessa população.

Mechanical reperfusion of acute right coronary artery occlusion after radiofrequency catheter ablation and long-term follow-up angiography.

Coronary artery injury is a rare complication of radiofrequency catheter ablation. We describe the case of a 12-year-old girl who had an acute distal right coronary artery (RCA) occlusion during radiofrequency catheter ablation of a postero-septal accessory pathway treated with mechanical reperfusion utilizing an angioplasty guidewire. Coronary angiography performed at 1-year follow-up depicted normal left ventricular function, patent descending posterior artery and total occlusion of the postero-lateral branch, which was filled through a rich collateral circulation from the RCA marginal branch.