Chronic Chagas disease can progress to myocardial involvement with intense fibrosis, which may predispose patients to sudden cardiac death through ventricular arrhythmia. The associations of myocardial fibrosis detected by cardiac magnetic resonance (CMR) parameters with non-sustained ventricular tachycardia (NSVT) were evaluated. This cross-sectional study included patients in early stages of Chagas disease (n = 47) and a control group (n = 15). Patients underwent cardiac evaluation, including CMR examination. Myocardial fibrosis assessment by CMR with measurement of late gadolinium enhancement (LGE), native T1, and extracellular volume (ECV) was performed.There was an increase in myocardial fibrosis CMR parameters and ventricular arrhythmias among different stages of Chagas disease, combined with a decrease in the left ventricular ejection fraction (LVEF) by CMR and also in the right ventricular systolic function by S' wave on tissue Doppler. Fibrosis mass and ECV were associated with the Rassi score, ventricular extrasystole, and E/e' ratio in a logistic regression model adjusted for age and gender. The ECV maintained an association with the presence of NSVT, even after adjustments for fibrosis mass and LVEF assessed by CMR. The receiver-operating characteristic area under the curve for global ECV (0.85; 95% CI: 0.71-0.99) and NSVT was greater than that for fibrosis mass (0.75; 95% CI: 0.54-0.96), although this difference was not statistically significant. Extracellular volume could be an early marker of increased risk of ventricular arrhythmia in Chagas disease, presenting an independent association with NSVT in the initial stages of chronic Chagas cardiomyopathy, even after adjustment for fibrosis mass and LVEF.

Chronic Chagas heart disease has different clinical manifestations including arrhythmias, heart failure, and stroke. Chest pain is one of the most common symptoms and when associated with changes in the electrocardiogram, such as T-wave changes, electrically inactive areas, and segmental wall motion abnormalities, may lead to a misdiagnosis of acute coronary syndrome (ACS). Here, we describe two patients with Chagas heart disease and syncope due to sustained ventricular tachycardia who were misdiagnosed with ACS, and discuss the role of novel imaging modalities in the differential diagnosis and risk stratification.

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Fundamentos:A ablação da região para-Hissiana é um desafi o devido ao risco de lesão inadvertida do feixe de His. A crioablação, pela sua progressão mais lenta, permite a interrupção da aplicação em caso de sinais de lesões indesejadas e adesividade do cateter durante as aplicações, o que tem tornado a crioablação o método ideal para esses pacientes. Objetivos: Demonstrar os resultados de uma série inicial de pacientes encaminhados para crioablação de vias para-hissianas. Pacientes e métodos: De abril de 2015 a agosto de 2017, 13 pacientes foram encaminhados para crioablação devido à necessidade de abordagem para-hissiana detectada em procedimentos prévios de ablação. Dos 13 pacientes, sete foram submetidos à tentativa de ablação por radiofrequência (RF) e apresentaram insucesso ou recidiva, cinco realizaram apenas estudos eletrofi siológicos, não sendo tentada a ablação, e um foi indicado primariamente. A idade média era 32 ± 16 anos. Onze pacientes tinham vias anômalas (VAs) manifestas, um oculta e um taquicardia por reentrada nodal (TRN) com sinais de bloqueio atrioventricular (AV) transitório durante RF. Aplicava-se um ciclo de 4 minutos seguido de mais um ciclo em caso de resultado positivo. Resultados: Dos 13 pacientes, 11 apresentaram sucesso agudo em eliminar a via acessória. Um paciente tinha múltiplas vias acessórias, sendo uma lateral direita e uma lateral esquerda. Nesse paciente foi possível apenas a ablação da via esquerda. Em todos os demais foi observado exuberante potencial hissiano no ponto de aplicação com sucesso. O paciente com TRN foi ablacionado na região M sem intercorrências. Foram necessárias quatro aplicações em média para eliminação da via acessória com sucesso. A temperatura local média foi de -74 ºC. Em cinco pacientes foi observada a ocorrência de bloqueio do ramo direito (BRD) de terceiro grau. Em um paciente foi interrompida a aplicação precocemente pelo BRD e não foi realizada a aplicação de bônus. Esse foi o único paciente com sucesso agudo que apresentou recidiva clínica. Em nenhum paciente foi observado BAV transitório. Não foram observadas complicações. Conclusão:A crioablação de vias para-hissianas e TRN em regiões mais circunvizinhas do His foi um método efi caz para tratamento nessa população de pacientes refratários ou recusados para tratamento por RF. A ocorrência de BRD agudo não parece um critério para interrupção das aplicações

Basis: the ablation of the para-Hisian region is a challenge due to the risk of inadvertent lesion of a bundle of His. Cryoablation, due to its slower progression, allows interruption of the application in case of signs of undesired lesions and catheter adhesion during the applications, which has made cryoablation the ideal method for these patients. Objectives: to demonstrate the results of an initial series of patients referred for cryoablation of para-Hisian pathways. Patients and methods: From April 2015 to August 2017, 13 patients were referred for cryoablation due to the necessity for a para-Hisian approach detected in previous ablation procedures. Of the 13 patients, seven were submitted a radiofrequency ablation attempt (RF) and presented failure or recurrence, five performed only electrophysiological studies, and no ablation was attempted, and one was indicated primarily. The mean age was 32 ± 16 years. Eleven patients had manifest anomalous pathways (APs), one hidden and one nodal reentrant tachycardia (NRT) with a transient atrioventricular block (AB) during RF. A cycle of 4 minutes followed by one more cycle in case of a positive result. Results: Of the 13 patients, 11 had an acute success in eliminating the accessory pathway. One patient had multiple accessory pathways, one right side, and one left side. In this patient, it was possible only the ablation of the left pathway. In all others, it was observed exuberant Hisian potential at the point of application with success. The patient with NRT was ablated in the M region without intercurrences. Four applications were required on average to eliminate the accessory pathway successfully. The mean local temperature was -74 ºC. In five patients, the occurrence of third-degree right branch block (RBB) was observed. In one patient, early application of RBB was interrupted and the bonus application was not applied. This wasthe only acutely successful patient who presented clinical recurrence. Transient AB was not observed in any patient. No complications were observed. Conclusion: Cryoablation of para-Hisian pathways and NRTs in regions surrounding the His was an effective method for treatment in this population of patients refractory or refused for RF treatment. The occurrence of acute RBB does not seem to be a criterion for the interruption of applications.