Ventricular bigeminy characterization in 24-h Holter monitoring from Andersen-Tawil patients: An initial proof of concept versus patients with ischemic heart disease.

AIM: To characterize ventricular bigeminy from 24-h Holter recordings of Andersen-Tawil syndrome (ATS) patients, a first comparison with a large database of post-myocardial infarction (post-MI) patients with frequent premature ventricular complexes (PVC) was performed. METHODS: Baseline Holter recordings from 6 ATS1 patients and 618 post-MI patients were analyzed to assess total number of PVC, quantification of coupling intervals (CI), total number of bigeminy episodes, and percentage of PVC in bigeminy. RESULTS: A non-significant difference in total number of PVCs, mean CI and CI standard deviation was found. The median number of episodes of bigeminy (1038 vs 1; p = 0.004) and of PVC in bigeminy (51.1 vs 0.1%; p = 0.002) was significantly higher in ATS1 patients. Having ≥42 episodes of bigeminy or ≥ 36.1% of PVC in bigeminy distinguish PVC from ATS from post-MI patients with a sensitivity and specificity >80%. CONCLUSION: In this first approach, patients with ATS had a characteristic burden of episodes of ventricular bigeminy, compared with post-MI patients.

Type 2 Diabetes Mellitus and Nonvalvular Atrial Fibrillation in Mexico: National Registries Raise a Red Flag.

Type 2 diabetes mellitus (T2DM) is one of the most common chronic diseases worldwide and is highly prevalent in Mexico, as 10.2% of the adult population harbors this condition. T2DM is usually associated with cardiovascular comorbidities, including arrhythmias. Metabolic impairment is one of the mechanisms that contribute to tissue remodeling that affects atrial structure, and concomitant, the cardiac conduction system, both could result in atrial fibrillation (AF). AF is estimated to affect more than a half million Mexicans, and its incidence is expected to keep rising. According to national registries, T2DM is present in 28.4% of Mexican patients with AF and the coexistence of both diseases is associated with a higher risk of stroke. In clinical practice, the CHA2DS2-VASc risk score is useful for stroke risk stratification in patients with AF to facilitate the adequate use of anticoagulation therapy. T2DM is among the items of the CHA2DS2-VASc score because it correlates with an intrinsic prothrombotic state. In this narrative review, we present information that highlights the need for optimal glucose control and adequate anticoagulation in subjects with T2DM and AF.

Cardiometabolic risk factors and antithrombotic treatment in a Mexican population with atrial fibrillation and heart failure with reduced ejection fraction.

INTRODUCTION: Heart failure in patients with non-valvular atrial fibrillation (NVAF) is two to three times more common than in individuals without NVAF. OBJECTIVE: To identify cardiometabolic risk factors (CMRF) and antithrombotic treatment in patients with NVAF and heart failure with reduced ejection fraction (HFrEF), and to determine if there were differences according to gender. METHODS: CMRF, pro-thrombotic risk, bleeding risk, and antithrombotic therapy were globally analyzed and according to gender. RESULTS: Out of 1,423 patients with NVAF, 336 had HFrEF. On average, females were older than males. There was no difference between genders with regard to the type of NVAF or direct oral anticoagulants use. Hypertension was more common in women. History of transient ischemic attack was reported in 3.6% of the patients and cerebrovascular event in 10%, without differences in terms of gender. The percentage of men with elevated embolic risk was higher, but without antithrombotic treatment, in comparison with women. CONCLUSIONS: Significant differences were found according to gender in patients with NVAF and HFrEF, both in CMRF and some comorbidities, as well as in antithrombotic treatment according to embolic and bleeding risk.

INTRODUCCIÓN: La insuficiencia cardiaca en pacientes con fibrilación auricular no valvular (FANV) es de dos a tres veces más frecuente que en individuos sin FANV. OBJETIVO: Identificar los factores de riesgo cardiometabólico (FRCM) y el tratamiento antitrombótico de pacientes con FANV e insuficiencia cardiaca con fracción de expulsión reducida (IC-FEr), y determinar si existen diferencias conforme al sexo. MÉTODOS: En forma global y de acuerdo con el sexo se analizaron FRCM, riesgo protrombótico, riesgo de sangrado y terapia antitrombótica. RESULTADOS: De 1423 pacientes con FANV, 336 tuvieron IC-FEr. Las mujeres promediaron mayor edad que los hombres. No hubo diferencia entre los sexos respecto al tipo de FANV o uso de anticoagulantes orales directos. La hipertensión arterial sistémica fue más frecuente en mujeres. Un 3.6 % de los pacientes reportó antecedente de ataque isquémico transitorio y 10 % de evento vascular cerebral, sin diferencias en cuanto al sexo. El porcentaje de hombres con riesgo embólico elevado fue mayor, pero sin tratamiento antitrombótico, en comparación con las mujeres. CONCLUSIONES: Se encontraron diferencias significativas de acuerdo con el sexo en pacientes con FANV e IC-FEr, tanto en FRCM y algunas comorbilidades, como en el tratamiento antitrombótico de acuerdo con el riesgo embólico y de sangrado.

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.

Clinical practice guidelines for diagnostic and treatment of the chronic heart failure.

Chronic heart failure continues to be one of the main causes of impairment in the functioning and quality of life of people who suffer from it, as well as one of the main causes of mortality in our country and around the world. Mexico has a high prevalence of risk factors for developing heart failure, such as high blood pressure, diabetes, and obesity, which makes it essential to have an evidence-based document that provides recommendations to health professionals involved in the diagnosis and treatment of these patients. This document establishes the clinical practice guide (CPG) prepared at the initiative of the Mexican Society of Cardiology (SMC) in collaboration with the Iberic American Agency for the Development and Evaluation of Health Technologies, with the purpose of establishing recommendations based on the best available evidence and agreed upon by an interdisciplinary group of experts. This document complies with international quality standards, such as those described by the US Institute of Medicine (IOM), the National Institute of Clinical Excellence (NICE), the Intercollegiate Network for Scottish Guideline Development (SIGN) and the Guidelines International Network (G-I-N). The Guideline Development Group was integrated in a multi-collaborative and interdisciplinary manner with the support of methodologists with experience in systematic literature reviews and the development of CPG. A modified Delphi panel methodology was developed and conducted to achieve an adequate level of consensus in each of the recommendations contained in this CPG. We hope that this document contributes to better clinical decision making and becomes a reference point for clinicians who manage patients with chronic heart failure in all their clinical stages and in this way, we improve the quality of clinical care, improve their quality of life and reducing its complications.

La insuficiencia cardiaca crónica sigue siendo unas de las principales causas de afectación en el funcionamiento y en la calidad de vida de las personas que la presentan, así como una de las primeras causas de mortalidad en nuestro país y en todo el mundo. México tiene una alta prevalencia de factores de riesgo para desarrollar insuficiencia cardiaca, tales como hipertensión arterial, diabetes y obesidad, lo que hace imprescindible contar con un documento basado en la evidencia que brinde recomendaciones a los profesionales de la salud involucrados en el diagnóstico y el tratamiento de estos pacientes. Este documento establece la guía de práctica clínica (GPC) elaborada por iniciativa de la Sociedad Mexicana de Cardiología (SMC) en colaboración con la Agencia Iberoamericana de Desarrollo y Evaluación de Tecnologías en Salud, con la finalidad de establecer recomendaciones basadas en la mejor evidencia disponible y consensuadas por un grupo interdisciplinario y multicolaborativo de expertos. Cumple con estándares internacionales de calidad, como los descritos por el Institute of Medicine de los Estados Unidos de América (IOM), el National Institute of Clinical Excellence (NICE) del Reino Unido, la Intercollegiate Network for Scottish Guideline Development (SIGN) de Escocia y la Guidelines International Network (G-I-N). El grupo de desarrollo de la guía se integró de manera interdisciplinaria con el apoyo de metodólogos con experiencia en revisiones sistemáticas de la literatura y en el desarrollo de GPC. Se llevó a cabo y se condujo metodología de panel Delphi modificado para lograr un nivel de consenso adecuado en cada una de las recomendaciones contenidas en esta GPC. Esperamos que este documento contribuya para la mejor toma de decisiones clínicas y se convierta en un punto de referencia para los clínicos que manejan pacientes con insuficiencia cardiaca crónica en todas sus etapas clínicas, y de esta manera logremos mejorar la calidad en la atención clínica, aumentar la calidad de vida de los pacientes y disminuir las complicaciones de la enfermedad.

Use of subcutaneous cardioverter-defibrillator. First cases reported from National Institute of Cardiology Ignacio Chávez-Mexico.

INTRODUCTION: The transvenous implantable cardioverter defibrillator (ICD) is the treatment of choice for the prevention of sudden cardiac death (SCD). Its use could be restricted when device-related infections occurs or in the pediatric population. In the later, an ICD represents a challenge, due to the minimal dimensions of the venous system in children, the length of the electrodes, the size of the generator, as well as the anatomical complexity in cases with associated congenital heart disease. OBJECTIVE: This article presents the first Mexican patients with a subcutaneous ICD (SC-ICD) implant as a therapy for the prevention of SCD. METHODS: The first four cases were implanted at the Ignacio Chávez National Institute of Cardiology with a SC-ICD (Emblem, Boston Scientific, USA), three of them were pediatric patients, including the first implant of this type of device in a pediatric patient in Latin America. The 3-incision and 2-incision techniques were used under general anesthesia. RESULTS: A successful implantation was obtained with the 3-incision technique in the first 2 cases and the last 2 with the 2-incision technique. Proper functioning of the device was corroborated in the operating room with proof of appropriate therapy (65 J) for ventricular fibrillation induced with 50 Hz stimulation. No immediate complications were observed. One patient had appropriate shocks two months after the implant. During follow-up, one child developed skin erosion at the level of the curve of the electrode on the sternum, with no signs of infection. In the operating room, the damaged skin was resected, the barrel and the fixation silk were removed, surgical lavage was performed, and the skin was closed again, thus avoiding removal of the system. CONCLUSIONS: The SC-ICD is an alternative therapy to the transvenous ICD. It can be considered first choice in subjects who do not require ventricular pacing, including pediatric patients. Skin complications can occur but do not pose a threat as venous complications of conventional ICDs.

INTRODUCCIÓN: El desfibrilador automático implantable (DAI) transvenoso es el tratamiento de elección para la prevención de muerte súbita (MS) cardiaca por arritmias ventriculares malignas. Su uso se puede ver limitado cuando existe infección del sistema de estimulación o en población pediátrica donde representa un reto por diversas razones, incluyendo: las mínimas dimensiones del sistema venoso de los niños, la longitud de los electrodos, el tamaño del generador, así como por la complejidad anatómica en casos de cardiopatía congénita asociada. OBJETIVO: El presente artículo tiene por objetivo presentar la primera serie de casos de pacientes mexicanos a los cuales se les implantó un DAI subcutáneo (DAI-SC) como terapia para la prevención de MS. MÉTODOS: Se presentan los cuatro primeros casos que fueron implantados en el Instituto Nacional de Cardiología Ignacio Chávez con un DAI-SC (Emblem, Boston Scientific, EE.UU.), tres de ellos eran pacientes pediátricos, incluyendo el primer implante de este tipo de dispositivo en un paciente pediátrico en América Latina. Las técnicas de tres y dos incisiones fueron empleadas bajo anestesia general. RESULTADOS: Se realizó el implante exitoso con técnica de tres incisiones en los dos primeros casos y con técnica de dos incisiones en los dos últimos casos. Se corroboró el adecuado funcionamiento del dispositivo en sala, con la verificación de terapia apropiada (65 J) de la fibrilación ventricular inducida mediante estimulación a 50 Hz. No hubo complicaciones inmediatas. Un paciente presentó descargas apropiadas a los dos meses del implante. En el seguimiento, un niño desarrolló erosión de la piel a nivel de la curva del electrodo en el esternón, sin datos de infección. En quirófano se resecó la piel dañada, se retiró el barril y la seda de fijación, se realizó lavado quirúrgico y se volvió a cerrar la piel, logrando así evitar el retiro del sistema. CONCLUSIONES: El DAI-SC es una terapia alternativa al DAI endovenoso y puede ser considerado de primera elección en aquellos casos que no requieran de estimulación ventricular, incluyendo pacientes pediátricos. Pueden ocurrir complicaciones cutáneas, pero no representan una amenaza como las complicaciones venosas de los DAI convencionales.

A machine learning approach to personalized predictors of dyslipidemia: a cohort study.

Introduction: Mexico ranks second in the global prevalence of obesity in the adult population, which increases the probability of developing dyslipidemia. Dyslipidemia is closely related to cardiovascular diseases, which are the leading cause of death in the country. Therefore, developing tools that facilitate the prediction of dyslipidemias is essential for prevention and early treatment. Methods: In this study, we utilized a dataset from a Mexico City cohort consisting of 2,621 participants, men and women aged between 20 and 50 years, with and without some type of dyslipidemia. Our primary objective was to identify potential factors associated with different types of dyslipidemia in both men and women. Machine learning algorithms were employed to achieve this goal. To facilitate feature selection, we applied the Variable Importance Measures (VIM) of Random Forest (RF), XGBoost, and Gradient Boosting Machine (GBM). Additionally, to address class imbalance, we employed Synthetic Minority Over-sampling Technique (SMOTE) for dataset resampling. The dataset encompassed anthropometric measurements, biochemical tests, dietary intake, family health history, and other health parameters, including smoking habits, alcohol consumption, quality of sleep, and physical activity. Results: Our results revealed that the VIM algorithm of RF yielded the most optimal subset of attributes, closely followed by GBM, achieving a balanced accuracy of up to 80%. The selection of the best subset of attributes was based on the comparative performance of classifiers, evaluated through balanced accuracy, sensitivity, and specificity metrics. Discussion: The top five features contributing to an increased risk of various types of dyslipidemia were identified through the machine learning technique. These features include body mass index, elevated uric acid levels, age, sleep disorders, and anxiety. The findings of this study shed light on significant factors that play a role in dyslipidemia development, aiding in the early identification, prevention, and treatment of this condition.

Inter-American Society of Cardiology (CIFACAH-ELECTROSIAC) and Latin-American Heart Rhythm Society (LAHRS): multidisciplinary review on the appropriate use of implantable cardiodefibrillator in heart failure with reduced ejection fraction.

BACKGROUND: Our main objective was to present a multidisciplinary review on the epidemiology of sudden cardiac death (SCD) and the tools that could be used to identify malignant ventricular arrhythmias (VAs) and to perform risk stratification. In addition, indications and contraindications for the use of implantable cardioverter defibrillator (ICD) in general and in special populations including the elderly and patients with chronic kidney disease (CKD) are also given. METHODS: An expert group from the Inter American Society of Cardiology (IASC), through their HF Council (CIFACAH) and Electrocardiology Council (ElectroSIAC), together with the Latin American Heart Rhythm Society (LAHRS), reviewed and discussed the literature regarding the appropriate use of an ICD in people with heart failure (HF) with reduced ejection fraction (HFpEF). Indications and contraindications for the use of ICD are presented in this multidisciplinary review. RESULTS: Numerous clinical studies have demonstrated the usefulness of ICD in both primary and secondary prevention of SCD in HFpEF. There are currently precise indications and contraindications for the use of these devices. CONCLUSIONS: In some Latin American countries, a low rate of implantation is correlated with low incomes, but this is not the case for all Latin America. Determinants of the low rates of ICD implantation in many Latin American countries are still a matter of research. VA remains one of the most common causes of cardiovascular death associated with HFrEF and different tools are available for stratifying the risk of SCD in this population.

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.

Case report: Challenges and implications of conduction system pacing in pediatrics: Case series.

Cardiac electrical stimulation in children usually is needed in the setting of complete congenital atrioventricular block, atrioventricular block after heart surgery, and bradycardia associated with some specific channelopathies. In cases of atrioventricular block, the high percentage of ventricular stimulation raises concern on the deleterious effects of chronic stimulation of the right ventricle. In recent years, physiologic stimulation has developed as a valid approach for adult patients and a great interest has risen in offering conduction system pacing also to the pediatric population. We present three pediatric cases of stimulation of the conduction system (His bundle or left bundle branch), in order to show the intrinsic particularities and challenges implied in these new techniques.

[Clinical guideline for diagnosis and treatment of atrial fibrillation]. / Guía de práctica clínica. Diagnóstico y tratamiento de la fibrilación auricular.

Atrial fibrillation (AF) is associated with long-term increase in the incidence of cerebrovascular disease, heart failure and mortality. The incidence of ischemic stroke in patients with non-valvular atrial fibrillation averages 5 % per year, from two to seven more frequent than in patients without atrial fibrillation (AF). One in six ischemic stroke occurs in patients with AF. The detection and accurate diagnosis and timely therapeutic intervention have shown a decrease in morbidity and mortality associated with this arrhythmia. The above data by themselves justify the development of a management guide and care for these patients. The purpose of this guide is to provide health professionals recommendations based on the best available evidence with the intent to standardize actions: diagnosis and identification of patients with atrial fibrillation; risk stratification and treatment according to the classification of atrial fibrillation; identification of the risk of thromboembolism and its prevention; and treatment guidelines to determine which patient will require to be referred promptly.

Genes frequently associated with sudden death in primary hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy is characterized by left ventricular hypertrophy without apparent cardiac justification. Sudden cardiac death may be the first manifestation of the disease. It occurs mainly in adulthood and can be seen in childhood and adolescence where genetic origin predominates. Primary HCM ("familial") is inherited in an autosomal dominant pattern in the 25 subtypes informed in Online Mendelian Inheritance in Man. The proteins encoded by the mutated genes are part of the sarcomere in the cardiac cells, being the thick filament the most frequently affected, with the worst prognosis. In the present article, we describe the Mendelian inheritance of the disease and the two most associated genes with sudden death: MYBPC3 and MYH7.

La miocardiopatía hipertrófica (MCH) es el aumento de grosor de la pared ventricular izquierda no relacionada con otras alteraciones cardíacas. Es una enfermedad que puede presentar como primera manifestación clínica la muerte súbita y de ahí su relevancia clínica. Aunque se presenta sobre todo en la edad adulta, puede aparecer durante la infancia y adolescencia, en las que predominan los casos de origen hereditario. La MCH primaria, de causa genética, muestra en particular un patrón de herencia autosómico dominante en los 25 subtipos reconocidos en OMIM (Online Mendelian Inheritance in Man). Las proteínas codificadas por los genes mutantes forman parte del sarcómero en células musculares cardíacas, y las variantes patogénicas de filamentos gruesos son las de mayor frecuencia y peor pronóstico. En este artículo se describen la herencia mendeliana de la enfermedad y la relación con muerte súbita de los genes más frecuentemente encontrados en ella: MYBPC3 y MYH7.

Excerpts from the documents of Mexican positions and recommendations in cardiovascular diseases and COVID-19.

The recommendations in which the Mexican Society of Cardiology (SMC) in conjunction with the National Association of Cardiologists of Mexico (ANCAM) as well as different Mexican medical associations linked to cardiology are presented, after a comprehensive and consensual review and analysis of the topics related to cardiovascular diseases in the COVID-19 pandemic. Scientific positions are analyzed and responsible recommendations on general measures are given to patients, with personal care, healthy eating, regular physical activity, actions in case of cardio-respiratory arrest, protection of the patient and health personnel as well as precise indications in the use of non-invasive cardiovascular imaging, prescription of medications, care in specific topics such as systemic arterial hypertension, heart failure, arrhythmias and acute coronary syndromes, in addition to emphasizing electrophysiology, interventionism, cardiac surgery and in cardiac rehabilitation. The main interest is to provide the medical community with a general orientation on what to do in daily practice and patients with cardiovascular diseases in the setting of this unprecedented epidemiological crisis of COVID-19.

Se presentan las recomendaciones en las cuales la Sociedad Mexicana de Cardiología (SMC) en conjunto con la Asociación Nacional de Cardiólogos de México (ANCAM), así como diferentes asociaciones médicas mexicanas vinculadas con la cardiología, después de una revisión y análisis exhaustivo y consensuado sobre los tópicos relacionados con las enfermedades cardiovasculares en la pandemia de COVID-19, se analizan posturas científicas y se dan recomendaciones responsables sobre medidas generales a los pacientes, con cuidados personales, alimentación saludable, actividad física regular, acciones en caso de paro cardiorrespiratorio, la protección del paciente y del personal de salud así como las indicaciones precisas en el uso de la imagen cardiovascular no invasiva, la prescripción de medicamentos, cuidados en tópicos específicos como en la hipertensión arterial sistémica, insuficiencia cardiaca, arritmias y síndromes coronarios agudos, además de hacer énfasis en los procedimientos de electrofisiología, intervencionismo, cirugía cardiaca y en la rehabilitación cardiaca. El interés principal es brindar a la comunidad médica una orientación general sobre el quehacer en la práctica cotidiana y pacientes con enfermedades cardiovasculares en el escenario esta crisis epidemiológica sin precedentes de COVID-19.

Atrial fibrillation in cardiac surgery.

Atrial fibrillation is the most frequent arrhythmia in the postoperative period of cardiac surgery. It is associated with heart failure, renal insufficiency, systemic embolism and increase in days of in-hospital and mortality. Atrial fibrillation in the postoperative period of cardiac surgery (FAPCC) usually appears in the first 48 h after surgery. The main mechanisms involved in the appearance and maintenance of FAPCC are the increase in sympathetic tone and the inflammatory response. The associated risk factors are advanced age, chronic obstructive pulmonary disease, chronic kidney disease, valve surgery, fraction of ejection of the left ventricle < 40% and the withdrawal of beta-blocker drugs. There are instruments that have been shown to predict the appearance of FAPCC. Prophylactic treatment with beta-blockers and amiodarone, is associated with a decrease in the appearance of FAPCC. Given its transient nature, it is suggested that the initial treatment of FAPCC be the heart rate control and only if the treatment does not achieve a return to sinus rhythm, the use of electrical cardioversion is suggested. It is unknown what should be the long-term follow-up and complications beyond this period are little known. FAPCC is not a benign or isolated arrhythmia in patients undergoing cardiac surgery, so the identification of risk factors, their prevention, and follow-up in the outpatient setting, should be part of the units dedicated to the care and care of these patients.

La fibrilación auricular es la arritmia más frecuente en el periodo posquirúrgico de la cirugía cardíaca. Se relaciona con insuficiencia cardíaca, insuficiencia renal, embolismo sistémico y más días de estancia y mortalidad. La fibrilación auricular en el periodo posquirúrgico de la cirugía cardíaca (FAPCC) suele aparecer en las primeras 48 horas. Los principales mecanismos que producen la aparición y el mantenimiento de la FAPCC son el aumento del tono simpático y la respuesta inflamatoria. Los factores de riesgo adjuntos son la edad avanzada, enfermedad pulmonar obstructiva crónica, enfermedad renal crónica, cirugía valvular, fracción de expulsión del ventrículo izquierdo menor de 40% e interrupción de fármacos bloqueadores ß. Existen instrumentos que han demostrado predecir la aparición de FAPCC. El tratamiento profiláctico con bloqueadores ß y amiodarona se relaciona con disminución de la aparición de FAPCC. Dada su naturaleza transitoria, se sugiere que el tratamiento inicial de FAPCC sea el control de la frecuencia cardíaca y sólo en caso de que el tratamiento no consiga el retorno al ritmo sinusal está indicada la cardioversión eléctrica. Se desconoce cuál debe ser el seguimiento a largo plazo y sólo se conocen en escasa medida las complicaciones más allá de este periodo. La FAPCC no es una arritmia benigna ni aislada en los pacientes sometidos a operación cardíaca, por lo que la identificación de los factores de riesgo, su prevención y el seguimiento en el ámbito ambulatorio deben formar parte de las unidades dedicadas a la atención y los cuidados de estos pacientes.

Type 2 Diabetes Mellitus and Nonvalvular Atrial Fibrillation in Mexico: National Registries Raise a Red Flag

ABSTRACT Type 2 diabetes mellitus (T2DM) is one of the most common chronic diseases worldwide and is highly prevalent in Mexico, as 10.2% of the adult population harbors this condition. T2DM is usually associated with cardiovascular comorbidities, including arrhythmias. Metabolic impairment is one of the mechanisms that contribute to tissue remodeling that affects atrial structure, and concomitant, the cardiac conduction system, both could result in atrial fibrillation (AF). AF is estimated to affect more than a half million Mexicans, and its incidence is expected to keep rising. According to national registries, T2DM is present in 28.4% of Mexican patients with AF and the coexistence of both diseases is associated with a higher risk of stroke. In clinical practice, the CHA2DS2-VASc risk score is useful for stroke risk stratification in patients with AF to facilitate the adequate use of anticoagulation therapy. T2DM is among the items of the CHA2DS2-VASc score because it correlates with an intrinsic prothrombotic state. In this narrative review, we present information that highlights the need for optimal glucose control and adequate anticoagulation in subjects with T2DM and AF.

Desfibrilador subcutáneo. Primeros casos en el Instituto Nacional de Cardiología, incluyendo dos pacientes pediátricos / Use of subcutaneous cardioverter-defibrillator. First cases reported from National Institute of Cardiology Ignacio Chávez-Mexico

Resumen Introducción: El desfibrilador automático implantable (DAI) transvenoso es el tratamiento de elección para la prevención de muerte súbita (MS) cardiaca por arritmias ventriculares malignas. Su uso se puede ver limitado cuando existe infección del sistema de estimulación o en población pediátrica donde representa un reto por diversas razones, incluyendo: las mínimas dimensiones del sistema venoso de los niños, la longitud de los electrodos, el tamaño del generador, así como por la complejidad anatómica en casos de cardiopatía congénita asociada. Objetivo: El presente artículo tiene por objetivo presentar la primera serie de casos de pacientes mexicanos a los cuales se les implantó un DAI subcutáneo (DAI-SC) como terapia para la prevención de MS. Métodos: Se presentan los cuatro primeros casos que fueron implantados en el Instituto Nacional de Cardiología Ignacio Chávez con un DAI-SC (Emblem, Boston Scientific, EE.UU.), tres de ellos eran pacientes pediátricos, incluyendo el primer implante de este tipo de dispositivo en un paciente pediátrico en América Latina. Las técnicas de tres y dos incisiones fueron empleadas bajo anestesia general. Resultados: Se realizó el implante exitoso con técnica de tres incisiones en los dos primeros casos y con técnica de dos incisiones en los dos últimos casos. Se corroboró el adecuado funcionamiento del dispositivo en sala, con la verificación de terapia apropiada (65 J) de la fibrilación ventricular inducida mediante estimulación a 50 Hz. No hubo complicaciones inmediatas. Un paciente presentó descargas apropiadas a los dos meses del implante. En el seguimiento, un niño desarrolló erosión de la piel a nivel de la curva del electrodo en el esternón, sin datos de infección. En quirófano se resecó la piel dañada, se retiró el barril y la seda de fijación, se realizó lavado quirúrgico y se volvió a cerrar la piel, logrando así evitar el retiro del sistema. Conclusiones: El DAI-SC es una terapia alternativa al DAI endovenoso y puede ser considerado de primera elección en aquellos casos que no requieran de estimulación ventricular, incluyendo pacientes pediátricos. Pueden ocurrir complicaciones cutáneas, pero no representan una amenaza como las complicaciones venosas de los DAI convencionales.

Abstract Introduction: The transvenous implantable cardioverter defibrillator (ICD) is the treatment of choice for the prevention of sudden cardiac death (SCD). Its use could be restricted when device-related infections occurs or in the pediatric population. In the later, an ICD represents a challenge, due to the minimal dimensions of the venous system in children, the length of the electrodes, the size of the generator, as well as the anatomical complexity in cases with associated congenital heart disease. Objective: This article presents the first Mexican patients with a subcutaneous ICD (SC-ICD) implant as a therapy for the prevention of SCD. Methods: The first four cases were implanted at the Ignacio Chávez National Institute of Cardiology with a SC-ICD (Emblem, Boston Scientific, USA), three of them were pediatric patients, including the first implant of this type of device in a pediatric patient in Latin America. The 3-incision and 2-incision techniques were used under general anesthesia. Results: A successful implantation was obtained with the 3-incision technique in the first 2 cases and the last 2 with the 2-incision technique. Proper functioning of the device was corroborated in the operating room with proof of appropriate therapy (65 J) for ventricular fibrillation induced with 50 Hz stimulation. No immediate complications were observed. One patient had appropriate shocks two months after the implant. During follow-up, one child developed skin erosion at the level of the curve of the electrode on the sternum, with no signs of infection. In the operating room, the damaged skin was resected, the barrel and the fixation silk were removed, surgical lavage was performed, and the skin was closed again, thus avoiding removal of the system. Conclusions: The SC-ICD is an alternative therapy to the transvenous ICD. It can be considered first choice in subjects who do not require ventricular pacing, including pediatric patients. Skin complications can occur but do not pose a threat as venous complications of conventional ICDs.

Corrected sinus node recovery time as a screening test in patients with typical atrial flutter post-ablation to predict pacemaker implantation / Tiempo de recuperación del nodo sinusal corregido como prueba de tamizaje en pacientes con aleteo atrial típico postablación para predecir la implantación de marcapasos

Abstract 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.

Resumen 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.

Factores de riesgo cardiometabólico y tratamiento antitrombótico en población mexicana con fibrilación auricular e insuficiencia cardiaca con fracción de expulsión reducida / Cardiometabolic risk factors and antithrombotic treatment in a Mexican population with atrial fibrillation and heart failure with reduced ejection fraction

Resumen Introducción: La insuficiencia cardiaca en pacientes con fibrilación auricular no valvular (FANV) es de dos a tres veces más frecuente que en individuos sin FANV. Objetivo: Identificar los factores de riesgo cardiometabólico (FRCM) y el tratamiento antitrombótico de pacientes con FANV e insuficiencia cardiaca con fracción de expulsión reducida (IC-FEr), y determinar si existen diferencias conforme al sexo. Métodos: En forma global y de acuerdo con el sexo se analizaron FRCM, riesgo protrombótico, riesgo de sangrado y terapia antitrombótica. Resultados: De 1423 pacientes con FANV, 336 tuvieron IC-FEr. Las mujeres promediaron mayor edad que los hombres. No hubo diferencia entre los sexos respecto al tipo de FANV o uso de anticoagulantes orales directos. La hipertensión arterial sistémica fue más frecuente en mujeres. Un 3.6 % de los pacientes reportó antecedente de ataque isquémico transitorio y 10 % de evento vascular cerebral, sin diferencias en cuanto al sexo. El porcentaje de hombres con riesgo embólico elevado fue mayor, pero sin tratamiento antitrombótico, en comparación con las mujeres. Conclusiones: Se encontraron diferencias significativas de acuerdo con el sexo en pacientes con FANV e IC-FEr, tanto en FRCM y algunas comorbilidades, como en el tratamiento antitrombótico de acuerdo con el riesgo embólico y de sangrado.

Abstract Introduction: Heart failure in patients with non-valvular atrial fibrillation (NVAF) is two to three times more common than in individuals without NVAF. Objective: To identify cardiometabolic risk factors (CMRF) and antithrombotic treatment in patients with NVAF and heart failure with reduced ejection fraction (HFrEF), and to determine if there were differences according to gender. Methods: CMRF, pro-thrombotic risk, bleeding risk, and antithrombotic therapy were globally analyzed and according to gender. Results: Out of 1,423 patients with NVAF, 336 had HFrEF. On average, females were older than males. There was no difference between genders with regard to the type of NVAF or direct oral anticoagulants use. Hypertension was more common in women. History of transient ischemic attack was reported in 3.6% of the patients and cerebrovascular event in 10%, without differences in terms of gender. The percentage of men with elevated embolic risk was higher, but without antithrombotic treatment, in comparison with women. Conclusions: Significant differences were found according to gender in patients with NVAF and HFrEF, both in CMRF and some comorbidities, as well as in antithrombotic treatment according to embolic and bleeding risk.

[Electroanatomic mapping system (CARTO) to perform catheter ablation of atrial fibrillation]. / La cartografía electroanatómica (CARTO) en la ablación de la fibrilación auricular.

Since the first report of radiofrequency catheter ablation curing atrial fibrillation (AF) nearly a decade ago, numerous techniques have evolved, from linear ablation to modify the reentrant sustrate for AF, to electrical isolation of pulmonary vein to eliminate triggers of AF, to hibrid approaches of circunferential ablation around and between the pulmonary veins and mitral valve annulus to modify both the triggers and sustrate for AF. We describe the electroanatomic mapping system (CARTO, Biosense Webster) and its use in patients undergoing catheter ablation for AF.