Amiodarone or implantable cardioverter-defibrillator in chagas cardiomyopathy: the CHAGASICS randomized clinical trial

IMPORTANCE: Over 10 000 people with Chagas disease experience sudden cardiac death (SCD) annually, mostly caused by ventricular fibrillation. Amiodarone hydrochloride and the implantable cardioverter-defibrillator (ICD) have been empirically used to prevent SCD in patients with chronic Chagas cardiomyopathy. OBJECTIVE: To test the hypothesis that ICD is more effective than amiodarone therapy for primary prevention of all-cause mortality in patients with chronic Chagas cardiomyopathy and moderate to high mortality risk, assessed by the Rassi score. DESIGN, SETTING, AND PARTICIPANTS: CHAGASICS is an open-label, randomized clinical trial. The study enrolled patients from 13 centers in Brazil from May 30, 2014, to August 13, 2021, with the last follow-up November 8, 2021. Patients with serological findings positive for Chagas disease, a Rassi risk score of at least 10 points (intermediate to high risk), and at least 1 episode of nonsustained ventricular tachycardia were eligible to participate. Data were analyzed from May 3, 2022, to June 16, 2023. INTERVENTIONS: Patients were randomized 1:1 to receive ICD or amiodarone (with a loading dose of 600 mg after randomization). MAIN OUTCOMES AND MEASURES: The primary outcome was all-cause mortality, and secondary outcomes included SCD, hospitalization for heart failure, and necessity of a pacemaker during the entire follow-up. RESULTS: The study was stopped prematurely for administrative reasons, with 323 patients randomized (166 in the amiodarone group and 157 in the ICD group), rather than the intended 1100 patients. Analysis was by intention to treat at a median follow-up of 3.6 (IQR, 1.8-4.4) years. Mean (SD) age was 57.4 (9.8) years, 185 patients (57.3%) were male, and the mean (SD) left ventricular ejection fraction was 37.0% (11.6%). There were 60 deaths (38.2%) in the ICD arm and 64 (38.6%) in the amiodarone group (hazard ratio [HR], 0.86 [95% CI, 0.60-1.22]; P = .40). The rates of SCD (6 [3.8%] vs 23 [13.9%]; HR, 0.25 [95% CI, 0.10-0.61]; P = .001), bradycardia requiring pacing (3 [1.9%] vs 27 [16.3%]; HR, 0.10 [95% CI, 0.03-0.34]; P < .001), and heart failure hospitalization (14 [8.9%] vs 28 [16.9%]; HR, 0.46 [95% CI, 0.24-0.87]; P = .01) were lower in the ICD group compared with the amiodarone arm. CONCLUSIONS AND RELEVANCE: In patients with chronic Chagas cardiomyopathy at moderate to high risk of mortality, ICD did not reduce the risk of all-cause mortality. However, ICD significantly reduced the risk of SCD, pacing need, and heart failure hospitalization compared with amiodarone therapy. Further studies are warranted to confirm the evidence generated by this trial.

Impacto do mapeamento dos potenciais diastólicos em pacientes chagásicos submetidos à ablação de taquicardia ventricular / Impact of mapping diastolic potentials in chagasic patients undergoing ventricular tachycardia ablation

INTRODUÇÃO: O advento das técnicas de modificação de substrato e dos cateteres de mapeamento multieletrodos ampliou o espectro de taquicardias ventriculares (TVs) mapeáveis. O mapeamento de alta definição proporcionou melhor agilidade, eficiência e resultados da ablação de TVs na população não chagásica. No entanto, o papel do mapeamento de potenciais diastólicos ainda não foi estudado na miocardiopatia chagásica, que apresenta desafios eletrofisiológicos peculiares. Este estudo tem como objetivo avaliar a frequência de mapeamento dos potenciais diastólicos e seu impacto na recorrência de TV em pacientes chagásicos submetidos à ablação. MÉTODOS: De um total de 56 pacientes submetidos a ablação de taquicardia ventricular cicatricial em nossa instituição no período de outubro de 2020 a outubro de 2023, foram analisados 36 pacientes portadores de miocardiopatia chagásica com seguimento mínimo de 1 ano. A ablação por radiofrequência foi direcionada às regiões com potenciais diastólicos, seguida pela modificação do substrato, com mapeamento epicárdico e endocárdico em todos os pacientes. Os desfechos a longo prazo foram correlacionados com a capacidade de mapear potenciais diastólicos. RESULTADOS: Foram induzidas 70 TVs no total, das quais 30 (42,9%) eram hemodinamicamente instáveis. O mapeamento da fase diastólica foi obtido em 46 TVs (65,7%). Dos 36 pacientes analisados, potenciais diastólicos foram identificados em 27 (75%) pacientes. Entre estes, 5 (18,5%) apresentaram recorrência de TV. Em contraste, dos 8 (22,2%) pacientes em que não foi possível identificar potenciais diastólicos, 2 (25%) apresentaram recorrência. CONCLUSÃO: Nesse estudo, o mapeamento dos potenciais diastólicos foi viável em uma proporção significativa de pacientes portadores de miocardiopatia chagásica e foi associado a menores taxas de recorrência de taquicardia ventricular.

Effect of dispersive electrode position (anterior vs. posterior) in epicardial radiofrequency ablation of ventricular wall: A computer simulation study.

An epicardial approach is often used in radiofrequency (RF) catheter ablation to ablate ventricular tachycardia when an endocardial approach fails. Our objective was to analyze the effect of the position of the dispersive patch (DP) on lesion size using computer modeling during epicardial approach. We compared the posterior position (patient's back), commonly used in clinical practice, to the anterior position (patient's chest). The model considered ventricular wall thicknesses between 4 and 8 mm, and electrode insertion depths between .3 and .7 mm. RF pulses were simulated with 20 W of power for 30 s duration. Statistically significant differences (P < .001) were found between both DP positions in terms of baseline impedance, RF current (at 15 s) and thermal lesion size. The anterior position involved lower impedance (130.8 ± 4.7 vs. 146.2 ± 4.9 Ω) and a higher current (401.5 ± 5.6 vs. 377.5 ± 5.1 mA). The anterior position created lesion sizes larger than the posterior position: 8.9 ± 0.4 vs. 8.4 ± 0.4 mm in maximum width, 8.6 ± 0.4 vs. 8.1 ± 0.4 mm in surface width, and 4.5 ± 0.4 vs. 4.3 ± 0.4 mm in depth. Our results suggest that: (1) the redirection of the RF currents due to repositioning the PD has little impact on lesion size and only affects baseline impedance, and (2) the differences in lesion size are only 0.5 mm wider and 0.2 mm deeper for the anterior position, which does not seem to have a clinical impact in the context of VT ablation.

Mechanical and electrical uncoupling: the role of cardiac magnetic resonance imaging in arrhythmogenic cardiomyopathy. Proof of concept.

OBJECTIVES: Arrhythmogenic cardiomyopathy (ACM) is a complex cardiac disorder associated with ventricular arrhythmias. Understanding the relationship between mechanical uncoupling and cardiac structural changes in ACM patients is crucial for improved risk stratification and management. METHODS: In this study, we enrolled 25 ACM patients (median age 34 years, 72% men) based on the 2019 Modified Task Force and Padua criteria. Patients were categorized by the presence or absence of clinically relevant ventricular tachycardia (crVT), necessitating emergency interventions. Right ventricular-arterial coupling (VAC) was assessed using echocardiography. Low-rank regression splines were employed to model left ventricular ejection fraction (LVEF) and right ventricular ejection fraction (RVEF) in relation to VAC. RESULTS: Positive associations were observed between VAC and LVEF (ρ = 0.472, p = 0.023), RVEF (ρ = 0.522, p = 0.038), and right ventricular (RV) indexed stroke volume (ρ = 0.79, p < 0.001). Patients with crVT exhibited correlations with RV shortening, reduced RVEF (39.6 vs. 32.2%, p = 0.025), increased left ventricular (LV) mass (38.99 vs. 45.55, p = 0.045), and LV end-diastolic volume (LVEDV) (56.99 vs. 68.15 mL/m2, p = 0.045). Positive associations for VAC were noted with LVEDV (p = 0.039) and LV mass (p = 0.039), while negative correlations were observed with RVEF by CMR (p = 0.023) and RV shortening by echocardiography (p = 0.026). CONCLUSIONS: Our findings underscore the significance of right VAC in ACM, demonstrating correlations with RV and LVEF, RV stroke volume, and clinically relevant arrhythmias. Insights into RVEF, LV mass, and end-diastolic volume provide valuable contributions to the understanding of ACM pathophysiology and may inform risk assessment strategies.

OBJETIVOS: La miocardiopatía arritmogénica (MCA) es un trastorno cardíaco complejo asociado con arritmias ventriculares (AV). Comprender la relación entre el desacoplamiento mecánico y los cambios estructurales cardíacos en pacientes con MCA es crucial para una estratificación de riesgos y una gestión mejorada. MÉTODOS: En este estudio, reclutamos a 25 pacientes con MCA (edad media 34 años, 72% hombres) basándonos en los criterios del Task Force 2019 y los criterios de Padua. Los pacientes se clasificaron según la presencia o ausencia de taquicardia ventricular clínicamente relevante (crVT), que requería intervenciones de emergencia. Se evaluó el acoplamiento ventricular derecho-arterial (VAC) mediante ecocardiografía. Se utilizaron low-rank regression splines para modelar la fracción de eyección del ventrículo izquierdo (FEVI) y la fracción de eyección del ventrículo derecho (FEVD) en relación con el VAC. RESULTADOS: Se observaron asociaciones positivas entre el VAC y la FEVI (ρ = 0.472, p = 0.023), la FEVD (ρ = 0.522, p = 0.038) y el volumen de eyección indexado del ventrículo derecho (ρ = 0.79, p < 0.001). Los pacientes con crVT mostraron correlaciones con acortamiento del ventrículo derecho, disminución de la FEVD (39.6 vs. 32.2%, p = 0.025), aumento de la masa ventricular izquierda (38.99 vs. 45.55, p = 0.045) y volumen diastólico final del ventrículo izquierdo (VDVI) (56.99 vs. 68.15 mL/m2, p = 0.045). Se observaron asociaciones positivas para el VAC con el VDVI (p = 0.039) y la masa ventricular izquierda (p = 0.039), mientras que se observaron correlaciones negativas con la FEVD por RMC (p = 0.023) y el acortamiento del ventrículo derecho por ecocardiografía (p = 0.026). CONCLUSIONES: Nuestros hallazgos subrayan la importancia del VAC derecho en la MCA, demostrando correlaciones con la FEVD y FEVI, el volumen de eyección del ventrículo derecho y arritmias clínicamente relevantes. Las percepciones sobre la FEVD, la masa ventricular izquierda y el volumen diastólico final proporcionan contribuciones valiosas para comprender la fisiopatología de la MCA y pueden informar estrategias de evaluación de riesgos.

Evaluation of patients with implantable cardioverter-defibrillator in a Latin American tertiary center.

INTRODUCTION: Despite advancements in implantable cardioverter-defibrillator (ICD) technology, sudden cardiac death (SCD) remains a persistent public health concern. Chagas disease (ChD), prevalent in Brazil, is associated with increased ventricular tachycardia (VT) and ventricular fibrillation (VF) events and SCD compared to other cardiomyopathies. METHODS: This retrospective observational study included patients who received ICDs between October 2007 and December 2018. The study aims to assess whether mortality and VT/VF events decreased in patients who received ICDs during different time periods (2007-2010, 2011-2014, and 2015-2018). Additionally, it seeks to compare the prognosis of ChD patients with non-ChD patients. Time periods were chosen based on the establishment of the Arrhythmia Service in 2011. The primary outcome was overall mortality, assessed across the entire sample and the three periods. Secondary outcomes included VT/VF events and the combined outcome of death or VT/VF. RESULTS: Of the 885 patients included, 31% had ChD. Among them, 28% died, 14% had VT/VF events, and 37% experienced death and/or VT/VF. Analysis revealed that period 3 (2015-2018) was associated with better death-free survival (p = .007). ChD was the only variable associated with a higher rate of VT/VF events (p < .001) and the combined outcome (p = .009). CONCLUSION: Mortality and combined outcome rates decreased gradually for ICD patients during the periods 2011-2014 and 2015-2018 compared to the initial period (2007-2010). ChD was associated with higher VT/VF events in ICD patients, only in the first two periods.

Taquicardia ventricular monomorfa sostenida secundaria a lipoma intramiocárdica / Sustained monomorphic ventricular tachycardia secondary to intramyocardial lipoma

[RESUMEN]. Introducción: A pesar de ser extremadamente raros, los tumores cardíacos conforman un importante desafío diagnóstico de la práctica cardiooncológica. Los lipomas son la segunda neoplasia primaria benigna en orden de frecuencia, representan entre un 8 a 12% de los tumores cardíacos primarios benignos en adultos. Materiales, métodos: Presentamos un caso clínico de una paciente estudiada y diagnosticada en nuestra institución. Descripción: Se presenta a una paciente de 21 años, de género femenino, sin factores de riesgo cardiovasculares, que fue referida a nuestra institución con diagnóstico de lipoma cardíaco. Su presentación inicial incluyó taquicardia ventricular sostenida con descompensación hemodinámica, que respondió favorablemente a la cardioversión eléctrica. Tras su ingreso, se llevaron a cabo estudios diagnósticos adicionales para obtener una caracterización más precisa de la masa y facilitar la toma de decisiones terapéuticas. El ecocardiograma transtorácico reveló la presencia de una masa en el septum interventricular basal, con extensión a la pared inferior de ambos ventrículos. La resonancia cardíaca posterior confirmó la naturaleza lipídica de la masa, que se presentaba de manera homogénea, con lí- mites definidos, sin realce en ninguna fase del contraste endovenoso y encapsulada, sin afectar estructuras adyacentes. La ausencia de realce precoz y tardío permitió descartar la vascularización y la presencia de tejido fibroso, respectivamente, consolidando así el diagnóstico de lipoma. Después de una evaluación exhaustiva por el equipo cardiovascular de nuestro hospital, se decidió de manera conjunta no proceder con una intervención quirúrgica debido a la ubicación anatómica del tumor y al elevado riesgo de morbimortalidad asociado. La alternativa consensuada fue la implantación de un cardiodesfibrilador, considerando el historial de arritmia severa y el riesgo de recurrencia en esta paciente. Conclusión: Se presenta un caso infrecuente de tumor cardíaco, que genera grandes desafíos diagnósticos y terapéuticos. Se optó por un tratamiento conservador con el propósito de prevenir la recurrencia de eventos arrítmicos.

[ABSTRACT]. Introduction: Despite being extremely rare, cardiac tumors pose a significant diagnostic challenge in cardio-oncology practice. Lipomas rank as the second most common primary benign neoplasm, accounting for 8 to 12% of primary benign cardiac tumors in adults. Materials and Methods: We present a clinical case of a patient studied and diagnosed at our institution. Description: A 21-year-old female patient, without cardiovascular risk factors, was referred to our institution with a diagnosis of cardiac lipoma. Her initial presentation included sustained ventricular tachycardia with hemodynamic decompensation, successfully managed with electrical cardioversion. Following admission, additional diagnostic studies were conducted to achieve a more precise characterization of the mass and guide therapeutic decision-making. Transthoracic echocardiography revealed a mass in the basal interventricular septum, extending to the inferior wall of both ventricles. Subsequent cardiac resonance confirmed the lipid nature of the mass, presenting homogeneously with well-defined borders, no enhancement in any phase of intravenous contrast, encapsulated, and without involvement of adjacent structures. The absence of early and late enhancement ruled out tumor vascularization and fibrous tissue, respectively, confirming the diagnosis of a lipoma. Following a comprehensive evaluation by our hospital's cardiovascular team, a joint decision was made to refrain from surgical intervention due to the anatomical location of the tumor and the associated high risk of morbidity and mortality. The consensus alternative was the implantation of a cardioverter-defibrillator, considering the patient's history of severe arrhythmia and the risk of recurrence. Conclusion: An infrequent case of cardiac tumor, that is associated with diagnostic and therapeutic challenges, is described. A conservative treatment was chosen aiming to prevent the recurrence of arrhythmic events.

Effect of ivabradine on ventricular arrhythmias in heart failure patients with reduced ejection fraction.

BACKGROUND/INTRODUCTION: Heart failure patients with reduced ejection fraction are at high risk for ventricular arrhythmias and sudden cardiac death. Ivabradine, a specific inhibitor of the If current in the sinoatrial node, provides heart rate reduction in sinus rhythm and angina control in chronic coronary syndromes. OBJECTIVE: The effect of ivabradine on ventricular arrhythmias in heart failure patients with reduced ejection fraction patients has not been fully elucidated. The aim of this study was to investigate the effect of ivabradine use on life-threatening arrhythmias and long-term mortality in heart failure patients with reduced ejection fraction patients. METHODS: In this retrospective study, 1,639 patients with heart failure patients with reduced ejection fraction were included. Patients were divided into two groups: ivabradine users and nonusers. Patients presenting with ventricular tachycardia, the presence of ventricular extrasystole, and ventricular tachycardia in 24-h rhythm monitoring, appropriate implantable cardioverter-defibrillator shocks, and long-term mortality outcomes were evaluated according to ivabradine use. RESULTS: After adjustment for all possible variables, admission with ventricular tachycardia was three times higher in ivabradine nonusers (95% confidence interval 1.5-10.2). The presence of premature ventricular contractions and ventricular tachycardias in 24-h rhythm Holter monitoring was notably higher in ivabradine nonusers. According to the adjusted model for all variables, 4.1 times more appropriate implantable cardioverter-defibrillator shocks were observed in the ivabradine nonusers than the users (95%CI 1.8-9.6). Long-term mortality did not differ between these groups after adjustment for all covariates. CONCLUSION: The use of ivabradine reduced the appropriate implantable cardioverter-defibrillator discharge in heart failure patients with reduced ejection fraction patients. Ivabradine has potential in the treatment of ventricular arrhythmias in heart failure patients with reduced ejection fraction patients.

[Electrocardiographic interval as a predictor of life-threatening arrhythmias in dilated cardiomyopathy patients]. / Intervalo electrocardiográfico como predictor de arritmias graves en pacientes con miocardiopatía dilatada.

Background: The Tpe interval (Tp-e) in the surface electrocardiogram represents ventricular repolarization, a key phase in the pathogenesis of severe ventricular arrhythmias. However, there are few studies evaluating changes in this electrocardiographic interval as a risk factor for serious arrhythmias in patients with dilated cardiomyopathy. Objective: To determine whether the Tp-e interval prolongation predicts the presence of life-threatening arrhythmias in patients with dilated cardiomyopathy (DCM) with implantable cardioverter-defibrillator (ICD). Material and methods: Analytical, cross-sectional study in patients with DCM with ICDs. The Tp-e interval was measured in the V2 electrocardiographic lead and correlated with the incidence of life-threatening arrhythmias identified by the ICD. Results: 53 patients were recruited, 10 (18.8%) presented life-threatening arrhythmias. Prolongation of Tp-e interval was related to an increase in the incidence of ventricular tachycardia/fibrillation tachycardia (VT/FT) with a mean of 93 ± 20.5 ms (p = 0.003), using ROC curves to determine the thereshold of 90 ms for increased risk of VT/VF with sensitivity of 70% and specificity of 84%, with an area under the curve of 0.798. Conclusion: The prolongation of the ITp-e interval greater than 90 ms in a population with dilated cardiomyopathy predicts the presence of arrhythmic episodes, such as VT and/or VT/FT.

Introducción: el intervalo Tpe (ITp-e) en el electrocardiograma de superficie representa la repolarización ventricular, fase clave en la patogénesis de arritmias ventriculares graves. Sin embargo, existen pocos estudios que evalúen la alteración de este intervalo electrocardiográfico como factor de riesgo de arritmias graves en pacientes con miocardiopatía dilatada. Objetivo: determinar si la prolongación del ITp-e predice la presencia de arritmias potencialmente mortales en pacientes con miocardiopatía dilatada (MCD) portadores de desfibrilador automático implantable (DAI). Material y métodos: estudio, transversal analítico en pacientes con MCD portadores de DAI. Se midió el ITp-e en la derivación electrocardiográfica V2 y se correlacionó con la incidencia de arritmias potencialmente letales identificadas por el DAI. Resultados: se incluyeron 53 pacientes, 10 (18.8%) presentaron arritmias potencialmente mortales. La prolongación del ITp-e se relacionó con aumento de incidencia de taquicardia ventricular/fibrilación ventricular (TV/FV) con media de 93 ± 20.5 ms (p = 0.003), por lo que se determinó mediante curvas ROC el punto de corte de 90 ms para el aumento de riesgo de TV/FV con sensibilidad de 70% y especificidad de 84%, con área bajo la curva de 0.798. Conclusión: la prolongación del intervalo ITp-e > 90 ms en población con miocardiopatía dilatada predice la presencia de episodios arrítmicos como TV o FV.

Prognostic Evaluation of Microvolt T-Wave Alternans in Hypertrophic Cardiomyopathy: 9-year Clinical Follow-up. / Avaliação Prognóstica da Microalternância da onda T na Cardiomiopatia Hipertrófica em um Seguimento Clínico de 9 anos.

BACKGROUND: Sudden cardiac death (SCD) resulting from ventricular arrhythmia is the main complication of hypertrophic cardiomyopathy (HCM). Microvolt T-wave alternans (MTWA) is associated with the occurrence of ventricular arrhythmias in several heart diseases, but its role in HCM remains uncertain. OBJECTIVE: To evaluate the association of MTWA with the occurrence of SCD or potentially fatal ventricular arrhythmias in HCM patients in a long-term follow-up. METHODS: Patients diagnosed with HCM and NYHA functional class I-II were consecutively selected. At the beginning of the follow-up, the participants performed the MTWA evaluation using the modified moving average during the stress test. The results were classified as altered or normal. The composite endpoint of SCD, ventricular fibrillation, sustained ventricular tachycardia (SVT) or appropriate implantable cardiac defibrillation (ICD) therapy was assessed. The level of significance was set at 5%. RESULTS: A total of 132 patients (mean age of 39.5 ± 12.6 years) were recruited and followed for a mean of 9.5 years. The MTWA test was altered in 74 (56%) participants and normal in 58 (44%). Nine events (6.8%) occurred during the follow-up, with a prevalence of 1.0%/year - six SCDs, two appropriate ICD shocks and one episode of (SVT). Altered MTWA was associated with non-sustained ventricular tachycardia on Holter (p = 0.016), septal thickness ≥30 mm (p < 0.001) and inadequate blood pressure response to effort (p = 0.046). Five patients with altered MTWA (7%) and four patients with normal MTWA (7%) had the primary outcome [OR = 0.85 (95% CI: 0.21 - 3.35, p=0.83)]. Kaplan-Meir event curves showed no differences between normal and altered MTWA. CONCLUSION: Altered MTWA was not associated with the occurrence of SCD or potentially fatal ventricular arrhythmias in HCM patients, and the low rate of these events during long-term follow-up suggests the good prognosis of this heart disease.

FUNDAMENTO: A morte súbita cardíaca (MSC), decorrente de arritmias ventriculares, é a principal complicação da cardiomiopatia hipertrófica (CMH). A microalternância da onda T (MAOT) está associada à ocorrência de arritmias ventriculares em diversas cardiopatias, mas seu papel na CMH permanece incerto. OBJETIVO: Avaliar associação da MAOT com a ocorrência de MSC ou arritmias ventriculares malignas em pacientes com CMH. MÉTODO: Pacientes com diagnóstico de CMH e classe funcional I-II (NYHA) foram selecionados de forma consecutiva. No início do seguimento os participantes realizaram a avaliação da MAOT pela metodologia da média móvel modificada no teste de esforço. Os resultados foram classificados em alterado ou normal. O desfecho foi composto por MSC, fibrilação ventricular, taquicardia ventricular sustentada (TVS) e terapia apropriada do cardioversor desfibrilador implantável (CDI). O nível de significância estatística foi de 5%. RESULTADOS: Um total de 132 pacientes (idade média de 39,5±12,6 anos) foram incluídos, com tempo de seguimento médio de 9,5 anos. A MAOT foi alterada em 74 (56%) participantes e normal em 58 (44%). Durante o seguimento, nove (6,8%) desfechos ocorreram, com prevalência de 1,0%/ano, sendo seis casos de MSC, dois choques apropriados do CDI e um episódio de TVS. MAOT alterada foi associada à taquicardia ventricular não sustentada no Holter (p=0,016), espessura septal≥30 mm (p<0,001) e resposta inadequada da pressão arterial ao esforço (p=0,046). Cinco pacientes (7%) e quatro pacientes (7%) com MAOT alterada e normal, respectivamente, apresentaram desfecho primário [OR=0,85(IC95%: 0,21­3,35, p=0,83)]. Curvas de eventos de Kaplan-Meir não apresentaram diferenças entre MAOT normal e alterada. CONCLUSÃO: A MAOT alterada não foi associada à ocorrência de MSC ou arritmias ventriculares potencialmente fatais em pacientes com CMH, e a baixa taxa desses eventos em um seguimento em longo prazo sugere o bom prognóstico dessa cardiopatia.

Taquicardia ventricular polimórfica tipo torsadess de pointes secundaria a estimulación por marcapasos / Polymorphic ventricular taquicardia "torsades de pointes" associated to abnormal pacemaker stimulation

La taquicardia ventricular polimórfica se origina en los ventrículos, cuyos complejos QRS son de morfología, amplitud y dirección variable, con frecuencias que oscilan entre 200 y 250 lpm, pudiendo ser autolimitadas o degenerar en una fibrilación ventricular. La TdP es un tipo de taquicardia ventricular polimórfica caracterizada por complejos con un eje eléctrico que gira alrededor de la línea isoeléctrica y que está asociada a QT largo. Se presenta el caso de una paciente portadora de marcapaso que presenta episodios de taquicardia ventricular polimórfica, con una morfología típica de TdP, sin documentación de QT prolongado previo ni actual, generada por la estimulación ventricular sobre onda T, de forma accidental por desplazamiento del electrodo auricular a Ventrículo Derecho (VD).

Polymorphic ventricular tachycardia is a tachycardia originating in the ventricles, where the QRS complexes have variable morphology, amplitude, and direction, with frequencies ranging between 200 and 250 bpm; it may be self-limited or degenerate into ventricular fibrillation. Torsades de Pointes (TdP) is a type of polymorphic ventricular tachycardia characterized by complexes with an electrical axis that rotates around the isoelectric line and that is associated with long QT interval. We present the case of a patient with a pacemaker who presents episodes of polymorphic ventricular tachycardia, with a typical morphology of TdP, without documentation of previous or current prolonged QT, generated by ventricular stimulation on the T wave, accidentally due to displacement of the atrial electrode to the Right Ventricle (RV).

Initial experience on cardiac magnetic resonance-aided VT ablation in South America.

BACKGROUND: Cardiac magnetic resonance (CMR) allowed to precisely identify the substrate in scar-related ventricular tachycardia (VT). New software has been developed to define the 3D scar and corridors to help VT ablation by integrating the scar and electroanatomical mapping (EAM). The objective of this study is to evaluate the results of VT ablation aided by the integration of EAM and CMR software processed scar. METHODS: We selected patients that underwent VT ablation with the integration of EAM and CMR processed using ADAS software and imported to the CARTO system using VTK file format. RESULTS: From 2019 to 2021, eight patients (mean age 63 ± 4.4, 62.5% male; EF 47 ± 12%) underwent CMR-aided VT ablation. Mean procedural time was 281 ± 77 min. There was of 9 ± 4.4 epicardial and 7.9 ± 4.3 endocardial bulls eye segments with at least 2 g of border zone or core scar. In a median follow-up time of 532 days (Q1: 284, Q3: 688), three patients (37.5%) presented VT recurrence, all three underwent a second procedure, with no VT recurrence on the follow-up. No patient died in the follow-up. CONCLUSION: CMR aided is ablation is feasible and effective in patients with scar related VT.

Improving Time to Defibrillation Following Ventricular Tachycardia (VTach) and Ventricular Fibrillation (VFib) Cardiac Arrest: A Multicenter Retrospective and Prospective Quality Improvement Study.

The goal of this study was to identify how often 2 independent centers defibrillated patients within the American Heart Association recommended 2-minute time interval following ventricular fibrillation/ventricular tachycardia arrest. A retrospective chart review revealed significant delays in defibrillation. Simulation sessions and modules were implemented to train nursing staff in a single nursing unit at a Philadelphia teaching hospital. Recruited nurses completed a code blue simulation session to establish a baseline time to defibrillation. They were then given 2 weeks to complete an online educational module. Upon completion, they participated in a second set of simulation sessions to assess improvement. First round simulations resulted in 33% with delayed defibrillation and 27% no defibrillation. Following the module, 77% of the second round of simulations ended in timely defibrillation, a statistically significant improvement ( P < 0.00001). Next steps involve prospective collection of the code blue data to analyze improvement in real code blue events.