Genomic analysis of an Ecuadorian individual carrying an SCN5A rare variant.

BACKGROUND: Ion channels, vital transmembrane protein complexes, regulate ion movement within cells. Germline variants in channel-encoding genes lead to channelopathies. The sodium channels in cardiac cells exhibit a structure of an alpha subunit and one to two beta subunits. The alpha subunit, encoded by the SCN5A gene, comprises four domains. CASE PRESENTATION: A fifteen-year-old Ecuadorian female with atrial flutter and abnormal sinus rhythm with no familial history of cardiovascular disease underwent NGS with the TruSight Cardio kit (Illumina). A likely pathogenic SCN5A gene variant (NM_188056.2:c.2677 C > Tp. Arg893Cys) was identified, associated with arrhythmias, long QT, atrial fibrillation, and Brugada syndrome. Ancestral analysis revealed a predominant European component (43.9%), followed by Native American (35.7%) and African (20.4%) components. CONCLUSIONS: The participant presents atrial flutter and conduction disorders, despite lacking typical cardiovascular risk factors. The proband carries a SCN5A variant that has not been previously reported in Latin America and may be associated to her phenotype. The documented arginine-to-cysteine substitution at position 893 in the protein is crucial for various cellular functions. The subject's mixed genetic composition highlights potential genetic contributors to atrial flutter, emphasizing the need for comprehensive genetic studies, particularly in mixed populations like Ecuadorians. This case underscores the importance of genetic analysis for personalized treatment and the significance of studying diverse genetic backgrounds in understanding cardiovascular diseases.

"NASCI case of the month: left ventricular apical hypoplasia".

Left ventricular apical hypoplasia is a rare congenital condition. It can cause nonspecific symptoms and can be accompanied by cardiac conduction system alterations such as bundle branch block, atrial flutter (AF) or atrial fibrillation. The diagnosis mostly is made by imaging.

Corrected sinus node recovery time as a screening test in patients with typical atrial flutter post-ablation to predict pacemaker implantation.

OBJECTIVE: The objective of the study was to establish the prognostic value of CSNRT regarding the necessity for pacemaker implantation in patients with atrial flutter (AFL) post-ablation. METHODS: This prospective cohort study, conducted at the National Institute of Cardiology "Ignacio Chavez" in Mexico City, assessed patients who had undergone ablation procedures to correct AFL, posterior to which an autonomic blockade was performed, and CSNRT was measured. RESULTS: The sample for this investigation was 40 patients. These were subdivided into two study groups depending on their requirement of pacemaker implant post-ablation (Pacemaker P, No Pacemaker NP). Sinus node (SN) dysfunction was diagnosed in 13 (32.5%) of the 40 participants, 10 (71.43%) of which required a pacemaker implant, while only 4 participants (28.57%) with normal SN function required pacemakers. Ten out of the 14 patients (71.43%) who required a pacemaker had an elevated CSNRT > 500 ms (p ≤ 0.01). Post-ablation CSNRT mean was 383.54 ms ± 67.96 ms in the NP group versus 1972.57 ms ± 3423.56 ms in the P group. Furthermore, SN pause in the P group had a mean of 1.86 s ± 0.96 s versus the NP group with 1.196 s ± 0.52 s. CONCLUSION: CSNRT has the potential to be a quantitative prognostic tool for the assessment of future pacemaker implants in patients with AFL post-ablation. This could aid in the timely diagnosis of sinus node dysfunction, which could, in the long run, result in the reduction of cardiac functional capacity loss due to cardiac remodeling.

OBJETIVO: Establecer el valor pronóstico del TRNSC basado en la necesidad de marcapasos en pacientes diagnosticados con aleteo atrial, pos-ablación. MÉTODOS: Este cohorte prospectivo, realizado en el Instituto Nacional de Cardiología "Ignacio Chávez" en la Ciudad de México, evaluó pacientes sometidos a ablación para corregir el aleteo atrial; se midió el TRNSC post bloqueo autonómico. RESULTADOS: La muestra de 40 pacientes se subdividió en 2 grupos según su requerimiento de marcapasos posterior a la ablación (P y NP). Se diagnosticó disfunción del nodo sinusal en 13 participantes (32.5%), de los cuales 10 (71.43%) requirieron marcapasos en comparación a 4 (28.57%) con función normal. En el grupo P la pausa del nodo sinusal post-ablación tuvo una media de 1.86 ± 0.96 s versus el grupo NP con 1.196 ± 0.52 s. En relación con el TRNSC, el grupo NP tuvo una media de 383.54 ± 67.96 ms vs. 1972.57 ± 3423.56 ms en el grupo P. 10 pacientes (25%) obtuvieron un TRNSC > 500 ms, de los cuales 100% requirieron marcapasos; de los 14 pacientes que requirieron marcapasos 10 (71.43%) tenían un TRNSC elevado (p ≤ 0.01). CONCLUSIONES: El TRNSC tiene el potencial de ser una herramienta de pronóstico cuantitativo para la necesidad de futuros implantes de marcapasos en pacientes con disfunción del nodo sinusal, resultado de aleteo atrial pos-ablación. Esto podría ayudar a diagnosticar más temprano una disfunción del nodo sinusal, resultando en la reducción de la pérdida a largo plazo de la función cardíaca como efecto de la remodelación.

Pathophysiology and treatment of adults with arrhythmias in the emergency department, part 1: Atrial arrhythmias.

PURPOSE: This article, the first in a 2-part review, aims to reinforce current literature on the pathophysiology of cardiac arrhythmias and various evidence-based treatment approaches and clinical considerations in the acute care setting. Part 1 of this series focuses on atrial arrhythmias. SUMMARY: Arrhythmias are prevalent throughout the world and a common presenting condition in the emergency department (ED) setting. Atrial fibrillation (AF) is the most common arrhythmia worldwide and expected to increase in prevalence. Treatment approaches have evolved over time with advances in catheter-directed ablation. Based on historic trials, heart rate control has been the long-standing accepted outpatient treatment modality for AF, but the use of antiarrhythmics is often still indicated for AF in the acute setting, and ED pharmacists should be prepared and poised to help in AF management. Other atrial arrhythmias include atrial flutter (AFL), atrioventricular nodal reentry tachycardia (AVNRT), and atrioventricular reentrant tachycardia (AVRT), which warrant distinction due to their unique pathophysiology and because each requires a different approach to utilization of antiarrhythmics. Atrial arrhythmias are typically associated with greater hemodynamic stability than ventricular arrhythmias but still require nuanced management according to patient subset and risk factors. Since antiarrhythmics can also be proarrhythmic, they may destabilize the patient due to adverse effects, many of which are the focus of black-box label warnings that can be overreaching and limit treatment options. Electrical cardioversion for atrial arrhythmias is generally successful and, depending on the setting and/or hemodynamics, often indicated. CONCLUSION: Atrial arrhythmias arise from a variety of mechanisms, and appropriate treatment depends on various factors. A firm understanding of physiological and pharmacological concepts serves as a foundation for exploring evidence supporting agents, indications, and adverse effects in order to provide appropriate care for patients.

Association of left ventricular abnormalities with incident cerebrovascular events and sources of thromboembolism in patients with chronic Chagas cardiomyopathy.

BACKGROUND: Although Chagas cardiomyopathy is related to thromboembolic stroke, data on risk factors for cerebrovascular events in Chagas disease is limited. Thus, we assessed the relationship between left ventricular (LV) impairment and cerebrovascular events and sources of thromboembolism in patients with Chagas cardiomyopathy. METHODS: This retrospective cohort included patients with chronic Chagas cardiomyopathy who underwent cardiovascular magnetic resonance (CMR). CMR was performed with a 1.5 T scanner to provide LV volumes, mass, ejection fraction (LVEF), and myocardial fibrosis. The primary outcome was a composite of incident ischemic cerebrovascular events (stroke or transient ischemic attack-TIA) and potential thromboembolic sources (atrial fibrillation (AF), atrial flutter, or intracavitary thrombus) during the follow-up. RESULTS: A total of 113 patients were included. Median age was 56 years (IQR: 45-67), and 58 (51%) were women. The median LVEF was 53% (IQR: 41-62). LV aneurysms and LV fibrosis were present in 38 (34%) and 76 (67%) individuals, respectively. The median follow-up time was 6.9 years, with 29 events: 11 cerebrovascular events, 16 had AF or atrial flutter, and two had LV apical thrombosis. In the multivariable model, only lower LVEF remained significantly associated with the outcomes (HR: 0.96, 95% CI: 0.93-0.99). Patients with reduced LVEF lower than 40% had a much higher risk of cerebrovascular events and thromboembolic sources (HR: 3.16 95% CI: 1.38-7.25) than those with normal LVEF. The combined incidence rate of the combined events in chronic Chagas cardiomyopathy patients with reduced LVEF was 13.9 new cases per 100 persons-year. CONCLUSIONS: LV systolic dysfunction is an independent predictor of adverse cerebrovascular events and potential sources of thromboembolism in patients with chronic Chagas cardiomyopathy.

Atrial flutter without structural heart disease in pediatrics: a retrospective review of cases in the Hospital Infantil Miguel Servet, Zaragoza, Spain.

BACKGROUND: Atrial flutter is a rare condition in pediatrics that usually occurs as a late complication after surgery for congenital heart diseases, although it can also appear in structurally normal hearts. CLINICAL CASES: We conducted a retrospective study of cases of atrial flutter with no structural heart disease diagnosed in a pediatric population (between 0 and 15 years of age) during 2015-2021 in a tertiary hospital. A total of seven cases were diagnosed, with a clear predominance of males (6/7). Of the seven patients, five debuted in the perinatal period: two were diagnosed at 20 and 36 hours of life, and three, prenatally. Among these perinatal cases, more than half (3/5) were preterm. The treatment was electrical cardioversion. The evolution was satisfactory in these cases, and there were no tachycardias in their subsequent development. In contrast, when the debut occurred at a later age (5-7 years), it was associated with channelopathy (Brugada syndrome and catecholaminergic polymorphic ventricular tachycardia), and electrical ablation of the ectopic focus was required due to poor response to pharmacological treatment. CONCLUSIONS: This study confirms the low incidence of this pathology in pediatrics and the benignity and good prognosis of neonatal flutter in most cases. The prognosis worsens when atrial flutter is diagnosed in older children, and the probability of concomitant associated heart disease increases.

INTRODUCCIÓN: El flutter o aleteo auricular es una patología poco frecuente en pediatría que suele presentarse como complicación tardía tras la cirugía de cardiopatías congénitas, aunque también puede aparecer en corazones estructuralmente normales. CASOS CLÍNICOS: Se llevó a cabo un estudio retrospectivo de los casos de flutter auricular sin cardiopatía estructural diagnosticados en una población pediátrica (entre 0 y 15 años de edad) durante el periodo 2015-2021 en un hospital terciario. En total fueron diagnosticados siete casos, con un claro predominio de varones (6/7). De los siete, cinco debutaron en periodo perinatal: dos fueron diagnosticados a las 20 y 36 horas de vida y tres de ellos, prenatalmente. Entre estos casos perinatales, más de la mitad (3/5) fueron pretérmino. El tratamiento fue la cardioversión eléctrica. La evolución fue satisfactoria en estos casos, y no se presentaron taquicardias en su evolución posterior. Por el contrario, cuando el debut se produjo en edades posteriores (5-7 años), se asoció con canalopatía (síndrome de Brugada y taquicardia ventricular polimorfa catecolaminérgica) que requirió de una ablación eléctrica del foco ectópico por escasa respuesta al tratamiento farmacológico. CONCLUSIONES: En este trabajo se confirma la baja incidencia de esta patología en pediatría, además de la benignidad y el buen pronóstico de flutter neonatal en la mayoría de casos. Cuando el diagnóstico se realiza en niños mayores, el pronóstico empeora, y aumenta la probabilidad de presentar de forma concomitante cardiopatías asociadas.

ablación de fibrilación auricular como tratamiento de primera línea: revisión de la literatura / Ablation as a first line treatment for atrial fibrillation: a review

RESUMEN La ablación con radiofrecuencia (RF) o con Criobalón (CRIO) en pacientes con fibrilación auricular (FA) paroxística y persistente es un tratamiento seguro y eficaz en pacientes seleccionados. Datos recientes demuestran que la ablación proporciona mejores resultados en comparación con fármacos antiarrítmicos (FAA) en el tratamiento de la FA temprana. Los estudios que comparan RF y CRIO mostraron una eficacia y seguridad comparables en el aislamiento de venas pulmonares (PVI) para pacientes con FA paroxística sintomática. OBJETIVOS: Revisar estudios clínicos que comparan el tratamiento de la FA con ablación versus FAA como terapia de primera línea en pacientes con FA sin tratamiento previo. La eficacia y la seguridad se compararán entre las dos cohortes y entre los subgrupos. MÉTODO: Se incluye un total de 6 estudios en los que participaron 1212 pacientes con FA: 609 pacientes fueron aleatorizados a ablación de FA y 603 a tratamiento farmacológico En comparación con el tratamiento con FAA, la ablación se asoció con una reducción en la recurrencia de arritmias auriculares (32,3 % frente a 53 %; riesgo relativo [RR], 0,62; IC del 95 %, 0,51-0,74; P < 0,001; I 2 = 40 %, NNT: 5). El uso de ablación también se asoció con una reducción de las arritmias auriculares sintomáticas (11,8 % frente a 26,4 %; RR, 0,44; IC del 95 %, 0,27-0,72; P = 0,001; I 2 = 54%) y hospitalización (5,6% vs 18,7%; RR, 0,32; IC 95%, 0,19-0,53; P< 0,001) sin diferencias significativas en los eventos adversos graves entre los grupos (4,2 % frente a 2,8 %; RR, 1,52; IC del 95 %, 0,81-2,85; P = 0,19). CONCLUSIÓN: En pacientes con FA paroxística, una estrategia de control precoz del ritmo cardíaco, se asocia con una mayor probabilidad de supervivencia, menos procedimientos repetidos, menos hospitalizaciones y, probablemente, una disminución en la progresión a FA persistente.

INTRODUCTION: Radiofrequency (RF) or cryoballoon (CRYO) ablation in patients with paroxysmal and persistent atrial fibrillation (AF) are safe and effective treatments in selected patients. Recent data show that ablation provides better results compared to antiarrhythmic drugs (AAD) in the treatment of early AF. Studies comparing RF and CRYO showed comparable efficacy and safety in pulmonary vein isolation (PVI) for patients with symptomatic paroxysmal AF. OBJETIVES: Review of clinical trials comparing treatment of AF with ablation versus AAD as first-line therapy in patients with AF with no previous treatment. Efficacy and safety are compared between the two cohorts and between subgroups. METHODS: A total of 6 studies involving -212 AF patients were included: 609 were randomized to AF ablation and 603 to pharmacological treatment. Ablation, compared with AAD, was associated with a reduction in recurrence of atrial arrhythmias (32.3% vs. 53%; relative risk [RR], 0.62; 95% CI, 0.51-0.74, P< 0.001, I2 = 40%, NNT: 5). The use of ablation was also associated with a reduction in symptomatic atrial arrhythmias (11.8% vs. 26.4%; RR, 0.44; 95% CI, 0.27-0.72; P= 0.001; I2 = 54%) and hospitalization (5.6% vs 18.7%; RR, 0.32; 95% CI, 0.19-0.53; P <0.001) with no significant differences in major adverse events (4.2% vs. 2.8%; RR, 1.52; 95% CI, 0.81-2.85; P=0.19). CONCLUSION: In patients with paroxysmal AF, an early cardiac rhythm control with ablation is associated with a higher probability of survival, fewer repeat procedures, fewer hospitalizations, and probably a decrease in progression to persistent AF.

Flutter auricular neonatal: presentación de tres casos / Neonatal atrial flutter: Presentation of three cases

Resumen Introducción: El flutter auricular es un tipo poco frecuente de arritmia fetal y neonatal. A pesar de que puede conducir a graves morbilidades, como hidrops fetal o incluso el fallecimiento, el diagnóstico y tratamiento precoz confieren un buen pronóstico a la mayoría de los casos. Pacientes y métodos: Se presentan tres casos de flutter auricular, dos de inicio en periodo fetal y uno en periodo neonatal, y se revisa la literatura en relación con las características clínicas, diagnósticas y terapéuticas del flutter auricular fetal y neonatal. Resultados y discusión: En el flutter auricular fetal la terapia materna con fármacos antiarrítmicos es el tratamiento más empleado durante la gestación. El tratamiento postnatal más utilizado es la cardioversión eléctrica sincronizada. El flutter auricular no suele asociar cardiopatía estructural; la recidiva neonatal es poco habitual y normalmente no precisa la administración de tratamiento profiláctico.

Abstract Introduction: Atrial flutter is a rare type of fetal and neonatal arrhythmia. Although it can lead to serious morbidities such as fetal hydrops or even death, diagnosis and early treatment confer a good prognosis in most cases. Patients and methods: Three cases of atrial flutter are presented, two of which start in the fetal period and one in the neonatal period. The literature is reviewed in relation to the clinical, diagnostic and therapeutic characteristics of fetal and neonatal atrial flutter. Results and discussion: In fetal atrial flutter maternal therapy with antiarrhythmic drugs is the most used treatment during pregnancy. The most used postnatal treatment is synchronized electrical cardioversion. Atrial flutter does not usually associate structural heart disease, neonatal recurrence is uncommon and usually does not require prophylactic treatment.

A randomized clinical trial to evaluate the efficacy and safety of rivaroxaban in patients with bioprosthetic mitral valve and atrial fibrillation or flutter: Rationale and design of the RIVER trial.

The efficacy and safety of rivaroxaban in patients with bioprosthetic mitral valves and atrial fibrillation or flutter remain uncertain. DESIGN: RIVER was an academic-led, multicenter, open-label, randomized, non-inferiority trial with blinded outcome adjudication that enrolled 1005 patients from 49 sites in Brazil. Patients with a bioprosthetic mitral valve and atrial fibrillation or flutter were randomly assigned (1:1) to rivaroxaban 20 mg once daily (15 mg in those with creatinine clearance <50 mL/min) or dose-adjusted warfarin (target international normalized ratio 2.0-30.); the follow-up period was 12 months. The primary outcome was a composite of all-cause mortality, stroke, transient ischemic attack, major bleeding, valve thrombosis, systemic embolism, or hospitalization for heart failure. Secondary outcomes included individual components of the primary composite outcome, bleeding events, and venous thromboembolism. SUMMARY: RIVER represents the largest trial specifically designed to assess the efficacy and safety of a direct oral anticoagulant in patients with bioprosthetic mitral valves and atrial fibrillation or flutter. The results of this trial can inform clinical practice and international guidelines.

Characterization of atrial arrhythmias in body surface potential mapping: A computational study.

PURPOSE: Atrial tachycardia (AT), flutter (AFL) and fibrillation (AF) are very common cardiac arrhythmias and are driven by localized sources that can be ablation targets. Non-invasive body surface potential mapping (BSPM) can be useful for early diagnosis and ablation planning. We aimed to characterize and differentiate the arrhythmic mechanisms behind AT, AFL and AF from the BSPM perspective using basic features reflecting their electrophysiology. METHODS: 19 simulations of 567-lead BSPMs were used to obtain dominant frequency (DF) maps and estimate the atrial driving frequencies using the highest DF (HDF). Regions with |DF-HDF|≤1Hz were segmented and characterized (size, area); the spatial distribution of the differences |DF-atrialHDFestimate| was qualitatively analyzed. Phase singularity points (SPs) were detected on maps generated with Hilbert transform after band-pass filtering around the HDF (±1Hz). Connected SPs along time (filaments) and their histogram (heatmaps) were used for rotational activity characterization (duration, spatiotemporal stability). Results were reproduced in clinical layouts (252 to 12 leads) and with different rotations and translations of the atria within the torso, and compared with the original 567-lead outcomes using structural similarity index (SSIM) between maps, sensitivity and precision in SP detection and direct feature comparison. Random forest and least-square based algorithms were used to classify the arrhythmias and their mechanisms' location, respectively, based on the obtained features. RESULTS: Frequency and phase analyses revealed distinct behavior between arrhythmias. AT and AFL presented uniform DF maps with low variance, while AF maps were more heterogeneous. Lower differences from the atrial HDF regions correlated with the driver location. Rotational activity was most stable in AFL, followed by AT and AF. Features were robust to lower spatial resolution layouts and modifications in the atrial geometry; DF and heatmaps presented decreasing SSIM along the layouts. The classification of the arrhythmias and their mechanisms' location achieved balanced accuracy of 72.0% and 73.9%, respectively. CONCLUSION: Non-invasive characterization of AT, AFL and AF based on realistic models highlights intrinsic differences between the arrhythmias, enhancing the BSPM utility as an auxiliary clinical tool.

Risco de Fibrilação Atrial após Ablação de Flutter Dependente de Istmo Cavo-Tricuspídeo: Vale a Pena Fazer a Ablação da FA Simultaneamente? / Risk of Atrial Fibrillation after Ablation of Cavotricuspid Isthmus-Dependent Atrial Flutter: Is Combined Ablation of Atrial Fibrillation Worthwhile?

Resumo Fundamento A ablação da fibrilação atrial (FA) e do flutter atrial dependente de istmo cavo-tricuspídeo (FLA-ICT) pode ser realizada simultaneamente quando as duas arritmias tenham sido registradas antes do procedimento. Entretanto, a melhor abordagem não é clara quando pacientes com FLA-ICT são encaminhados para ablação sem o registro prévio de FA. Objetivos Avaliar a prevalência e identificar os preditores de ocorrência do primeiro episódio de FA após ablação de FLA-ICT em pacientes sem o registro prévio de FA. Métodos Coorte retrospectiva de pacientes submetidos exclusivamente a ablação por cateter para FLA-ICT, sem registro prévio de FA. As características clínicas foram comparadas entre os grupos em que houve ocorrência de FA pós-ablação de FLA-ICT vs. sem ocorrência de FA. O nível de significância estatística adotado foi de 5%. Na análise de preditores, o desfecho primário avaliado foi ocorrência de FA após ablação de FLA-ICT. Resultados De um total de 227 pacientes submetidos a ablação de FLA-ICT (110 com registro de FA e 33 sem seguimento adequado), 84 pacientes foram incluídos, dos quais 45 (53,6%) apresentaram FA pós-ablação. Não houve variáveis preditoras de ocorrência de FA. Os escores HATCH e CHA2DS2-VASC foram semelhantes nos dois grupos. As taxas de recorrência de FLA-ICT e complicações após a ablação foram de 11,5% e 1,2%, respectivamente. Conclusões A ablação de FLA-ICT é eficaz e segura, mas 50% dos pacientes desenvolvem FA após ablação. Entretanto, ainda é incerto o papel da ablação combinada (FLA-ICT e FA) visando prevenção da ocorrência de FA. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

Abstract Background Simultaneous ablation of atrial fibrillation (AF) and cavotricuspid isthmus (CTI)-dependent atrial flutter can be performed when both arrythmias had been recorded before the procedure. However, the best approach has not been defined in case of patients referred for ablation with CTI-dependent atrial flutter, without history of AF. Objectives To assess the prevalence and to identify predictors of the first episode of AF after ablation of CTI-dependent atrial flutter in patients without history of AF. Methods Retrospective cohort of patients with CTI-dependent atrial flutter without history of AF undergoing catheter ablation. Clinical characteristics were compared between patients who developed AF and those who did not have AF after the procedure. Significance level was set at 5%. In the analysis of predicting factors, the primary outcome was occurrence of AF after CTI-dependent atrial flutter ablation. Results Of a total of 227 patients undergoing ablation of CTI-dependent atrial flutter (110 with history of AF and 33 without adequate follow-up), 84 were included, and 45 (53.6%) developed post-ablation AF. The HATCH and CHA2DS2-VASC scores were not different between the groups. Recurrence rate of CTI-dependent atrial flutter and complication rate were 11.5% and 1.2%, respectively, after ablation. Conclusions Although ablation of CTI-dependent atrial flutter is a safe and effective procedure, 50% of the patients developed AF after the procedure. However, the role of combined ablation (CTI-dependent atrial flutter plus AF) aiming at preventing AF is still uncertain. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

Risk of Atrial Fibrillation after Ablation of Cavotricuspid Isthmus-Dependent Atrial Flutter: Is Combined Ablation of Atrial Fibrillation Worthwhile? / Risco de Fibrilação Atrial após Ablação de Flutter Dependente de Istmo Cavo-Tricuspídeo: Vale a Pena Fazer a Ablação da FA Simultaneamente?

BACKGROUND: Simultaneous ablation of atrial fibrillation (AF) and cavotricuspid isthmus (CTI)-dependent atrial flutter can be performed when both arrythmias had been recorded before the procedure. However, the best approach has not been defined in case of patients referred for ablation with CTI-dependent atrial flutter, without history of AF. OBJECTIVES: To assess the prevalence and to identify predictors of the first episode of AF after ablation of CTI-dependent atrial flutter in patients without history of AF. METHODS: Retrospective cohort of patients with CTI-dependent atrial flutter without history of AF undergoing catheter ablation. Clinical characteristics were compared between patients who developed AF and those who did not have AF after the procedure. Significance level was set at 5%. In the analysis of predicting factors, the primary outcome was occurrence of AF after CTI-dependent atrial flutter ablation. RESULTS: Of a total of 227 patients undergoing ablation of CTI-dependent atrial flutter (110 with history of AF and 33 without adequate follow-up), 84 were included, and 45 (53.6%) developed post-ablation AF. The HATCH and CHA2DS2-VASC scores were not different between the groups. Recurrence rate of CTI-dependent atrial flutter and complication rate were 11.5% and 1.2%, respectively, after ablation. CONCLUSIONS: Although ablation of CTI-dependent atrial flutter is a safe and effective procedure, 50% of the patients developed AF after the procedure. However, the role of combined ablation (CTI-dependent atrial flutter plus AF) aiming at preventing AF is still uncertain. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0).

FUNDAMENTO: A ablação da fibrilação atrial (FA) e do flutter atrial dependente de istmo cavo-tricuspídeo (FLA-ICT) pode ser realizada simultaneamente quando as duas arritmias tenham sido registradas antes do procedimento. Entretanto, a melhor abordagem não é clara quando pacientes com FLA-ICT são encaminhados para ablação sem o registro prévio de FA. OBJETIVOS: Avaliar a prevalência e identificar os preditores de ocorrência do primeiro episódio de FA após ablação de FLA-ICT em pacientes sem o registro prévio de FA. MÉTODOS: Coorte retrospectiva de pacientes submetidos exclusivamente a ablação por cateter para FLA-ICT, sem registro prévio de FA. As características clínicas foram comparadas entre os grupos em que houve ocorrência de FA pós-ablação de FLA-ICT vs. sem ocorrência de FA. O nível de significância estatística adotado foi de 5%. Na análise de preditores, o desfecho primário avaliado foi ocorrência de FA após ablação de FLA-ICT. RESULTADOS: De um total de 227 pacientes submetidos a ablação de FLA-ICT (110 com registro de FA e 33 sem seguimento adequado), 84 pacientes foram incluídos, dos quais 45 (53,6%) apresentaram FA pós-ablação. Não houve variáveis preditoras de ocorrência de FA. Os escores HATCH e CHA2DS2-VASC foram semelhantes nos dois grupos. As taxas de recorrência de FLA-ICT e complicações após a ablação foram de 11,5% e 1,2%, respectivamente. CONCLUSÕES: A ablação de FLA-ICT é eficaz e segura, mas 50% dos pacientes desenvolvem FA após ablação. Entretanto, ainda é incerto o papel da ablação combinada (FLA-ICT e FA) visando prevenção da ocorrência de FA. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0).