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Since December 2019 we have observed the rapid advance of the severe acute respiratory syndrome caused by the new coronavirus (SARS-CoV-2). The impact of the clinical course of a respiratory infection is little known in patients with hereditary arrhythmias, due to the low prevalence of these diseases. Patients who present with infectious conditions may exacerbate hidden or well-controlled primary arrhythmias, due to several factors, such as fever, electrolyte disturbances, drug interactions, adrenergic stress and, eventually, the septic patient's own myocardial damage. The aim of this review is to highlight the main challenges we may encounter during the Covid 19 pandemic, specifically in patients with hereditary arrhythmias, with emphasis on the congenital long QT syndrome (LQTS), Brugada syndrome (SBr), ventricular tachycardia polymorphic catecholaminergic (CPVT) and arrhythmogenic right ventricular cardiomyopathy.Desde dezembro de 2019, observamos o rápido avanço da síndrome respiratória aguda grave causada pelo coronavírus 2019 (SARS-CoV-2). O impacto da evolução clínica de uma infecção respiratória é pouco conhecido em pacientes portadores de arritmias hereditárias, devido à baixa prevalência dessas doenças. Os pacientes que apresentam quadros infecciosos podem exacerbar arritmias primárias ocultas ou bem controladas, por diversos fatores, tais como febre, distúrbios eletrolíticos, interações medicamentosas, estresse adrenérgico e, eventualmente, o próprio dano miocárdico do paciente séptico. O objetivo desta revisão é destacar os principais desafios que podemos encontrar durante a pandemia pela Covid 19, especificamente nos pacientes com arritmias hereditárias, com destaque para a síndrome do QT longo congênito (SQTL), a síndrome de Brugada (SBr), a taquicardia ventricular polimórfica catecolaminérgica (TVPC) e a cardiomiopatia arritmogênica do ventrículo direito.

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

Introducao Em dezembro de 2019, foram relatados os primeiros casos da doenca causada pelo novo coronavirus (COVID-19), originarios de Wuhan, China. Desde a declaracao de pandemia em marco de 2020 por Organizacao Mundial da Saude (OMS), com disseminacao intercontinental, vivenciamos intensa busca por um tratamento seguro e eficaz. Estudos in vitro demonstraram algum efeito da cloroquina contra o novo coronavirus, intermediada pela glicosilacao dos receptores celulares de SARS-CoV e pelo aumento do pH endossomico, bloqueando a invasao celular pelo virus. [...]

OBJECTIVE To compare the prevalence of esophageal and periesophageal thermal injury in patients undergoing radiofrequency (RF) atrial fibrillation (AF) ablation using 8 mm tip catheters during three different esophageal protection strategies. METHODS Forty-five consecutive patients with paroxysmal or persistent AF underwent first ablation procedure, besides esophagogastroduodenoscopy (EGD) combined with radial endosonography (EUS) performed before and after the pulmonary vein (PV) isolation. Before the procedure, patients were randomly assigned to one of three esophageal lesion protection strategies: group I-without any protective or monitoring dispositive and limiting RF applications to 30 W for 20 seconds, in left atrium posterior wall (LAPW); group II-power and time of RF delivery, up to 50 W for 20 seconds at LAPW, limited by esophageal temperature monitoring; group III-applications of RF in LAPW with fixed power application of 50 W for 20 seconds during continuous esophageal cooling. RESULTS Baseline characteristics of patients were similar in all groups. The four PVs were isolated in 14 (93.3%), 13 (86.7%), and 15 (100%) patients, respectively in groups I, II, and III. The mean RF power was significantly higher (P

The atrioventricular (AV) reentrant tachycardia (AVRT) is the most common cause of supraventricular tachycardia (SVT) in the young pediatric population. Some newborns might present with congestive heart failure and require interventional treatment. Catheter ablation in small infants (

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

Background— Autonomic denervation is an alternative approach for patients with symptomatic bradycardia. No consensus exists on the critical targets and end points of the procedure. The aim of this study was to identify immediate end points and critical atrial regions responsible for vagal denervation. Methods and Results— We enrolled 14 patients (50% men; age: 34.0±13.8 years) with cardioinhibitory syncope, advanced atrioventricular block or sinus arrest, and no structural heart disease. Anatomic mapping of ganglionated plexuses was performed, followed by radiofrequency ablation. Heart rate, sinus node recovery time, Wenckebach cycle length, and atrial-His (AH) interval were measured before and after every radiofrequency pulse. Wilcoxon signed-rank test was used for comparison. Significant shortening of the R-R interval ( P =0.0009), Wenckebach cycle length ( P =0.0009), and AH intervals ( P =0.0014) was observed after ablation. The heart rate elevation was 23.8±12.5%, and the Wenckebach cycle length and AH interval shortening was 18.1±11% and 24.6±19%, respectively. Atropine bolus injection (0.04 mg/kg) did not increase heart rate further. Targeting a single spot of the left side (64% of the patients) or right side (36%) of the interatrial septum was observed to be responsible for ≥80% of the final R-R and AH interval shortening during ablation. Conclusions— Targeting specific sites of the interatrial septum is followed by an increase in heart rate and atrioventricular nodal conduction properties and might be critical for vagal attenuation. The R-R interval, Wenckebach cycle length, and AH interval shortening, associated with a negative response to atropine, could be considered immediate end points of the procedure.

OBJETIVOS: Avaliar se a ablacao com radiofrequencia e um procedimento eficiente para o tratamento das extra-sistoles da via de saida do ventriculo direito (EVSVD), e se resulta em melhora dos sintomas. METODOS: Estudo prospectivo, com 30 pacientes consecutivos (idade media de 40±13 anos, 25 do sexo feminino), sem cardiopatia estrutural aparente, com EVSVD, muito frequentes (densidade media de 1.263±593/h), sintomaticos por mais de 1 ano (media =74 meses) e refratarios aos farmacos antiarritmicos (3±1,7, incluindo os beta-bloqueadores), que foram submetidos a ablacao com radiofrequencia. RESULTADOS: Apos o primeiro procedimento, houve 23 sucessos iniciais (76,6%) e 7 iniciais insucessos (23,4%). Quatro pacientes tiveram recorrencias, sendo que dois desses nao se submeteram ao segundo procedimento. O segundo procedimento foi realizado em 9 pacientes (7 insucessos iniciais e 2 recorrencias), e o sucesso ocorreu em 5 pacientes adicionais, sendo 1 caso por acesso epicardico. A taxa de sucesso final foi de 80% (24/30), e nenhuma complicacao maior ocorreu. Apos um seguimento medio de 14±6 meses, no grupo de sucesso final houve uma reducao de mais de 90% na densidade das extra-sistoles(24/24; p

OBJETIVOS: Trabalho prospectivo, randomizado para comparar a eficacia e a seguranca do cateter irrigado em relacao ao cateter com eletrodo distal de 8 mm para ablacao com radiofrequencia (RF) do flutter atrial. METODOS: Em 52 pacientes consecutivos referidos para tratamento do flutter atrial tipico, a ablacao do istmo cavotricuspideo (Ist-CT) foi realizada com cateter de irrigacao fechada (n=26) ou com cateter de eletrodo distal de 8 mm (n=26). Os pulsos de RF foram aplicados ponto a ponto por 60 segundos com potencia limitada a 50 w com o cateter irrigado e por controle de temperatura (60oC, 70 w) com cateter de 8 mm. O criterio de fim do procedimento foi a obtencao de bloqueio bidirecional do Ist-CT. RESULTADOS: O bloqueio Ist-CT foi obtido em 98,1% dos pacientes. O "crossover" ocorreu em quatro pacientes do grupo com cateter irrigado. Nao se encontrou diferenca estatistica significante em relacao aos parâmetros da ablacao, tais como tempo total de aplicacao de RF (591,1±309,0s vs 486,2±250,8s), duracao do procedimento (86,4 ± 23,6 vs 78,1±22,5min) e tempo de fluoroscopia (17,0±6,7 vs 15,4±4,6min) entre os dois grupos. Durante seguimento medio de 10,6 meses, um paciente do grupo irrigado apresentou recorrencia do flutter atrial tipico. CONCLUSAO: A ablacao do Ist-CT resultou ser efetiva e segura para o controle do flutter atrial com ambas as tecnicas empregadas (cateter com eletrodo distal de 8 mm e cateter irrigado). A complexidade tecnica do cateter irrigado proporciona menor competitividade.

A reentrant mechanism related to a ventricular scar is the main mechanism of monomorphic VT in the setting of structural heart diseases. The surviving muscles in the scar areas are the main targets for VT ablation, identified as fragmented and late potentials. Identification of critical fibers involved in the circuit is usually performed during stable VT by using traditional entraining techniques. However, since many patients present hemodynamic instability, nonsustained VTs, or multiple morphologies, substrate mapping during sinus rhythm is an acceptable strategy for such patients. Electroanatomic mapping is an essential tool for identifying the possible channels that are targeted by endocardial and epicardial RF linear lesions. Such strategy produces a marked reduction in VT recurrences being increasingly applied for patients with unmappable VT and may be combined with other mapping approaches in patients with mappable VTs.

In the last decade, radio-frequency catheter ablation of atrial and ventricular tachycardia has become progressively common, driven predominantly by increasing success and low complication rates. At the same time, there was no significant development in antiarrhythmic drug effectiveness that still present limited efficacy and frequent side effects. As patients with congenital heart disease that have undergone surgical repair or palliation have been getting older, a wide variety of rhythm disturbances have been detected. Although electrophysiological procedures often are problematic due to the complex anatomy of such patients, a high level of success can be achieved with careful attention to surgical history and modern imaging technology. Thus, nowadays, interventional electrophysiological techniques play a major role in their management.

FUNDAMENTO: Diversos mecanismos podem estar envolvidos no desencadeamento da sincope em pacientes com cardiomiopatia hipertrofica (CMH), incluindo colapsos hemodinâmicos que podem estar relacionados a um desequilibrio autonomico. OBJETIVO: Avaliar e comparar a funcao autonomica de pacientes que apresentam CMH com sincope inexplicada (SI) com os que nao apresentam sincope. METODOS: Trinta e sete pacientes foram incluidos, sendo 16 com SI e 21 sem sincope. Sua funcao autonomica foi avaliada por sensibilidade barorreflexa (SB) espontânea e induzida por fenilefrina, pela variabilidade da frequencia cardiaca (VFC) no dominio do tempo durante o Holter de 24 horas e no dominio da frequencia (analise espectral), ambos em decubito dorsal e no teste de inclinacao (TI) a 70o. RESULTADOS: A SB espontânea mostrou-se semelhante em ambos os grupos (16,46 ± 12,99 vs. 18,31 ± 9,88 ms/mmHg, p = 0,464), assim como a SB induzida por fenilefrina (18,33 ± 9,31 vs. 15,83 ± 15,48 ms/mmHg, p = 0,521). Nao foram observadas diferencas no SDNN (137,69 ± 36,62 vs . 145,95 ± 38,07 ms, p = 0,389). O grupo com sincope apresentou um RMSSD significativamente menor (24,88 ± 10,03 vs. 35,58 ± 16,43 ms, p = 0,042) e tendencia a menor pNN50 (4,51 ± 3,78 vs . 8,83 ± 7,98%, p =0,085) e a menores valores do componente de alta frequencia da analise espectral da VFC em repouso (637,59 ± 1.295,53 vs. 782,65 ± 1.264,14 ms2 , p = 0,075). Nenhuma diferenca significativa foi observada em resposta ao TI (p = 0,053). A sensibilidade, especificidade e acuracia do TI na identificacao da etiologia da SI em pacientes com CMH foram 6%, 66% e 40%, respectivamente. CONCLUSAO: Observou-se tonus parassimpatico mais baixo em pacientes com CMH e SI, mas a relevância clinica deste achado ainda nao esta clara. O TI nao e uma ferramenta vantajosa para avaliar a origem da sincope em tais doentes, principalmente por causa da sua baixa especificidade.

Radiofrequency ablation (RFA) in children is an increasingly common practice.To evaluate, in our institution, the results of RFA in children younger than 15 years.A total of 125 children submitted to RFA between May 1991 and May 2010 were analyzed.Sixty-seven (53.6%) children were males, aged between 44 days and 15 years (mean 8.6 ± 3.3 years) with median weight of 31 kg. Heart disease was present in 21 (16.8%) patients. The RFA of accessory pathways (AP) was the most common procedure (62 children - 49.6%). The RFA of nodal reentrant tachycardia (NRT) was the second most common arrhythmia in 27 (21.6%), followed by atrial tachycardia (AT) in 16 (12.8%) and ventricular tachycardias (VT) in 8 (6.4%) children. The success criteria were achieved in 86.9%, 96.1%, 80% and 62.5% of patients undergoing RFA of AP, NRT, AT and VT, respectively. Transient AVB occurred during RFA in 4 (3.2%) and LBBB in 7 (5.6%) children. Twenty-five children underwent a new RFA due to initial failure or recurrence. During the mean follow up of 5.5 ± 3.4 years, 107 (88.4%) remained without recurrence. There was no statistical difference regarding the results and the age at which the patient underwent the procedure. No child had persistent AVB or required a permanent pacemaker.Catheter ablation is a safe and effective alternative therapy in children with recurrent tachycardias refractory to medical treatment.

The occurrence of atrial fibrillation (AF) after successful ablation of cavotricuspid isthmus-dependent atrial flutter (CTI-AFL) is an important medical event, but predictors of this event are still controversial.To determine the incidence of AF and its predictors in patients undergoing ablation of cavotricuspid isthmus-dependent atrial flutter (CTI-AFL).Fifty two patients with CTI-AFL underwent ablation from January 2003 to March 2004, in Instituto do Coração (InCor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo.During the mean follow-up period of 26.2 +/- 9.2 months, 16 (30.8%) patients presented AF. The univariate analysis revealed two clinical variables as predictive of the occurrence of AF after ablation of CTI-AFL for three years or longer (RR: 3.00; p = 0.020). In the multivariate analysis, these factors were independent variables associated with the occurrence of AF after ablation of CTI-AFL.AF is frequently observed during the follow-up of patients undergoing ablation of CTI-AFL. Persistent CTI-AFL and history of arrhythmia for more than three years are predictors of the occurrence of AF during the clinical follow-up.