The INVICTUS rheumatic heart disease research program: Rationale, design and baseline characteristics of a randomized trial of rivaroxaban compared to vitamin K antagonists in rheumatic valvular disease and atrial fibrillation.

BACKGROUND: Rheumatic heart disease (RHD) is a neglected disease affecting 33 million people, mainly in low and middle income countries. Yet very few large trials or registries have been conducted in this population. The INVICTUS program of research in RHD consists of a randomized-controlled trial (RCT) of 4500 patients comparing rivaroxaban with vitamin K antagonists (VKA) in patients with RHD and atrial fibrillation (AF), a registry of 17,000 patients to document the contemporary clinical course of patients with RHD, including a focused sub-study on pregnant women with RHD within the registry. This paper describes the rationale, design, organization and baseline characteristics of the RCT and a summary of the design of the registry and its sub-study. Patients with RHD and AF are considered to be at high risk of embolic strokes, and oral anticoagulation with VKAs is recommended for stroke prevention. But the quality of anticoagulation with VKA is poor in developing countries. A drug which does not require monitoring, and which is safe and effective for preventing stroke in patients with valvular AF, would fulfill a major unmet need. METHODS: The INVestIgation of rheumatiC AF Treatment Using VKAs, rivaroxaban or aspirin Studies (INVICTUS-VKA) trial is an international, multicentre, randomized, open-label, parallel group trial, testing whether rivaroxaban 20 mg given once daily is non-inferior (or superior) to VKA in patients with RHD, AF, and an elevated risk of stroke (mitral stenosis with valve area ≤2 cm2, left atrial spontaneous echo-contrast or thrombus, or a CHA2DS2VASc score ≥2). The primary efficacy outcome is a composite of stroke or systemic embolism and the primary safety outcome is the occurrence of major bleeding. The trial has enrolled 4565 patients from 138 sites in 23 countries from Africa, Asia and South America. The Registry plans to enroll an additional 17,000 patients with RHD and document their treatments, and their clinical course for at least 2 years. The pregnancy sub-study will document the clinical course of pregnant women with RHD. CONCLUSION: INVICTUS is the largest program of clinical research focused on a neglected cardiovascular disease and will provide new information on the clinical course of patients with RHD, and approaches to anticoagulation in those with concomitant AF.

Time-Frequency Analysis of Cardiovascular and Cardiorespiratory Interactions During Orthostatic Stress by Extended Partial Directed Coherence.

In this study, the linear method of extended partial directed coherence (ePDC) was applied to establish the temporal dynamic behavior of cardiovascular and cardiorespiratory interactions during orthostatic stress at a 70° head-up tilt (HUT) test on young age-matched healthy subjects and patients with orthostatic intolerance (OI), both male and female. Twenty 5-min windows were used to analyze the minute-wise progression of interactions from 5 min in a supine position (baseline, BL) until 18 min of the orthostatic phase (OP) without including pre-syncopal phases. Gender differences in controls were present in cardiorespiratory interactions during OP without compromised autonomic regulation. However in patients, analysis by ePDC revealed considerable dynamic alterations within cardiovascular and cardiorespiratory interactions over the temporal course during the HUT test. Considering the young female patients with OI, the information flow from heart rate to systolic blood pressure (mechanical modulation) was already increased before the tilt-up, the information flow from systolic blood pressure to heart rate (neural baroreflex) increased during OP, while the information flow from respiration to heart rate (respiratory sinus arrhythmia) decreased during the complete HUT test. Findings revealed impaired cardiovascular interactions in patients with orthostatic intolerance and confirmed the usefulness of ePDC for causality analysis.

Complete remission with histamine blocker in a patient with intractable hyperadrenergic postural orthostatic tachycardia syndrome secondary to long coronavirus disease syndrome.

The COVID-19 pandemic caused by the novel severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), has emerged as a global public health concern and its sequels have barely started to outcrop. A good percentage of patients who suffered from COVID-19 are prone to develop long-COVID or post-COVID condition (PCC), a multisystemic, heterogeneous, chronic disorder. Patients with PCC may experience diverse manifestations, of which cardiovascular and neurological symptoms are among the most frequently reported. Indeed, dysautonomia presented as orthostatic intolerance has gained room following recent reports linking postural orthostatic tachycardia syndrome (POTS) with PCC. Disturbances in heart rate (HR) and blood pressure (BP) during postural changes are the cornerstones of orthostatic intolerance seen in patients suffering from PCC. A subtype of POTS, hyperadrenergic POTS, has been widely studied because of its association with mast cell activation syndrome (MCAS). Although a causative relationship between PCC, hyperadrenergic POTS, and MCAS remains unrevealed, these syndromes can overlap. We want to propose here a correlation produced by a close-loop mechanism with positive feedback established after SARS-CoV-2 infection in a previously healthy young patient.

[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.

Hemodynamic profiles related to circulatory shock in cardiac care units.

One-third of the population in intensive care units is in a state of circulatory shock, whose rapid recognition and mechanism differentiation are of great importance. The clinical context and physical examination are of great value, but in complex situations as in cardiac care units, it is mandatory the use of advanced hemodynamic monitorization devices, both to determine the main mechanism of shock, as to decide management and guide response to treatment, these devices include pulmonary flotation catheter as the gold standard, as well as more recent techniques including echocardiography and pulmonary ultrasound, among others. This article emphasizes the different shock mechanisms observed in the cardiac care units, with a proposal for approach and treatment.

Un tercio de la población de pacientes en unidades de cuidados intensivos se encuentran en choque circulatorio, el identificarlo y determinar su mecanismo de manera rápida y eficaz es de gran importancia. El contexto clínico y el examen físico son de gran utilidad, sin embargo existen situaciones de alta complejidad en las que se requiere del uso de las distintas modalidades de monitorización hemodinámica avanzada, tanto para determinar la causa, como para decidir el manejo y guiar respuesta al tratamiento, incluyendo el catéter de flotación pulmonar como gold standard, así como técnicas más recientes incluyendo ecocardiografía y ultrasonido pulmonar, entre otros. Este artículo enfatiza los distintos mecanismos de choque observados en las unidades de cuidados cardiacos, con propuesta de abordaje y tratamiento.

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.

[Clinical predictors of ventricular arrhythmia storms in Chagas cardiomyopathy patients with implantable defibrillators]. / Predictores clínicos de tormenta arrítmica en pacientes con cardiomiopatía Chagásica con un desfibrilador automático implantable.

OBJECTIVES: To define the predictive factors of electrical storm (ES) in patients with Chronic Chagas Heart Disease (CCh) with an implantable cardioverter defibrillator (ICD). MATERIAL AND METHODS: We retrospectively studied 21 consecutive patients with CCh in whom an ICD was implanted between April 2005 and December 2008, with a mean follow up of 867 days. Patients were classified into two groups according to the presence of electrical storm episodes. We compared baseline characteristics, medical treatment and determinants of ventricular function. P values less than 0.05 were considered statistically significant. RESULTS: Of the 21 patients with CCh there were eight women (37%), mean age 61 years and an EF of 30%. It was noted at least one episode of arrhythmic storm in 9 cases (incidence of 43%). The total number of episodes of arrhythmic storm was 13 and the number of ventricular arrhythmias in each episode of arrhythmic storm was 15.6 (range 3-61). A trigger was identified in only two cases (pulmonary infectious process and decompensation of chronic heart failure). After analyzing the possible predictors of arrhythmic storm was found that a greater percentage of subjects with this complication had an EF <35% (89% vs. 50%, p = 0.01) and NYHA functional class III (66% vs. 8.3%, p = 0.001). In contrast, a lower percentage of subjects with arrhythmic storm were under beta-blocker treatment (55% vs. 100%, p = 0.01). CONCLUSIONS: In subjects with CCh with an ICD, the following variables are predictive of arrhythmic storm: EF <35%, NYHA functional class III-IV and absence of beta-blocker treatment.

[Case report: idiopathic ventricular tachycardia from the aortic sinus cusp]. / Informe de un caso: taquicardia ventricular idiopática en el seno de Valsalva izquierdo.

Idiopathic ventricular tachycardia is identified in 10% of the patients presenting with ventricular tachycardia, and they consist of various subtypes that can originate from different areas, including the aortic cusps which represent 0.7% of the total. Electrocardiographically, these ventricular tachycardias display a left bundle branch block pattern and inferior axis, and although rare, should be considered in the differential diagnosis with tachycardias originating from the septal region of the right ventricular outflow tract, which comprise 80% of the idiopathic ventricular tachycardias. Despite the vicinity of the left coronary artery ostium, radiofrequency catheter ablation can be curative in more than 90% of cases with a low risk (< 1% of serious complication). Therefore, it must be considered first-line therapy in patients who have failed or are intolerant to therapy with antiarrhythmic agents. The aim of this article is to describe the first case reported in Mexico of a successful ablation idiopathic ventricular tachycardia from the aortic sinus cusp in a patient with incessant ventricular tachycardia.

Left atrial longitudinal strain by speckle tracking as independent predictor of recurrence after electrical cardioversion in persistent and long standing persistent non-valvular atrial fibrillation.

Atrial fibrillation (AF) is the most common arrhythmia in humans. After successful cardioversion, there is a recurrence of 60% due to atrial remodeling, and it has been shown that the global peak atrial longitudinal strain (GPALS) is decreased in these subjects. The aim of this study was to evaluate the predictive value of GPALS for AF recurrence. A prospective cohort of patients with persistent (PnVAF) and long standing persistent non-valvular AF (LSPnVAF) which underwent electrical cardioversion was evaluated with standard echocardiographic variables and GPALS quantification. The primary endpoint was AF recurrence at 6 months. We included PnVAF (n = 50, aged 68.4 ± 10.2 years, female 46%, lasted AF 6 months) and LSPnVAF (n = 81, aged 66.5 ± 13.1 years, female 36%, lasted AF 18 months). At 6 months there were a 68% of recurrence of AF in PnVAF and 53% in LSPnVAF group. GPALS was lower in recurrence 7.8 ± 2.0% versus 21.2 ± 8.9% (p < 0.001) for PnVAF and 7.3 ± 2.7% versus 20.7 ± 7.6% (p < 0.001) in LSPnVAF. GPALS ≤ 10.75% discriminates recurrence at 6 months with a sensitivity of 85%, specificity 99%, PPV 85%, NPV 90%, LR + 8.5 and LR- 0.17. The independent predictors of recurrence in PnVAF were GPALS ≤ 10.75% HR 8.89 [(2.2-35.7), p < 0.01] meanwhile in LSPnVAF were age HR 1.039 [(1.007-1.071), p = 0.01], and GPALS ≤ 10.75% HR 28.1 [(7.2-109.1), p < 0.001]. In subjects with PnVAF and LSPnVAF with successful electrical cardioversion, GPALS ≤ 10.75% predicts arrhythmia recurrence at 6-month follow-up.

Temporal Analysis of Cardiovascular and Respiratory Complexity by Multiscale Entropy Based on Symbolic Dynamics.

The effect of an orthostatic stress on cardiovascular and respiratory complexity was investigated to detect impaired autonomic regulation in patients with vasovagal syncope (VVS). A total of 16 female patients and 12 age-matched healthy female subjects were enrolled in a passive 70° head-up tilt test. Also, 12 age-matched healthy male subjects were enrolled to study gender differences. Analysis was performed dynamically using various short-term (5 min) windows shifted by 1 min as well as by 20 min of orthostatic phase (OP) to evaluate local and global complexity. Complexity was determined over multiple time scales by the established method of refined composite multiscale entropy (RCMSE) and by a new proposed method of multiscale entropy based on symbolic dynamics (MSE-SD). Concerning heart rate variability (HRV) during OP, both methods revealed the highest complexity for female controls followed by lower complexity in male controls (p < 0.01) and by the lowest complexity in female patients (p < 0.01). For blood pressure variability (BPV), no gender differences in controls were shown by any method. However, MSE-SD demonstrated highly significantly increased BPV complexity in patients during OP (p < 0.01 on 4 time-scales after 7 min, p < 0.001 on 5 time-scales after 11 min) while RCMSE did not reveal considerable differences (p < 0.05 on 2 time scales after 7 min). Respiratory complexity was further increased in patients primary shown by MSE-SD. Findings indicated impaired autonomic regulation in VVS patients characterized by predominantly increased BPV complexity accompanied with decreased HRV complexity. In addition, results suggested extending the concept of complexity loss with disease.

Dynamics of the cardiovascular autonomic regulation during orthostatic challenge is more relaxed in women.

Linear dynamic analysis of cardiovascular and respiratory time series was performed in healthy subjects with respect to gender by shifted short-term segments throughout a head-up tilt (HUT) test. Beat-to-beat intervals (BBI), systolic (SYS) and diastolic (DIA) blood pressure and respiratory interval (RESP) time series were acquired in 14 men and 15 women. In time domain (TD), the descending slope of the auto-correlation function (ACF) (BBI_a31cor) was more pronounced in women than in men (p<0.05) during the HUT test and considerably steeper (p<0.01) at the end of orthostatic phase (OP). The index SYS_meanNN was slightly but significantly lower (p<0.05) in women during the complete test, while higher respiratory frequency and variability (RESP_sdNN) were found in women (p<0.05), during 10-20 min after tilt-up. In frequency domain (FD), during baseline (BL), BBI-normalized low frequency (BBI_LFN) and BBI_LF/HF were slightly but significantly lower (p<0.05), while normalized high frequency (BBI_HFN) was significantly higher in women. These differences were highly significant from the first 5 min after tilt-up (p<0.01) and highly significant (p<0.001) during 10-14 min of OP. Findings revealed that men showed instantaneously a pronounced and sustained increase in sympathetic activity to compensate orthostatism. In women, sympathetic activity was just increased slightly with delayed onset without considerably affecting sympatho-vagal balance.

[Design of an atrial fibrillation and embolic risk registry in Mexico: CARMEN-AF]. / Diseño de un registro de fibrilación auricular y riesgo embólico en México: CARMEN-AF.

OBJECTIVE: Atrial fibrillation (AF) is one of the most common arrhythmias, and its prevalence increase with age. It is associated with high risk of stroke. The prevention of such thromboembolism is done with oral anticoagulants, which in our country seem to be underused. CARMEN-AF registry aims primarily to determine the current status of thromboprophylaxis of non-valvular AF in Mexico. A secondary objective is to know the morbidity and mortality associated with non-valvular AF in at least one year of follow-up. METHODS: CARMEN-AF registry is an observational, longitudinal, multicenter, and national survey about the use of oral anticoagulants in patients with non-valvular AF. Patients 18years old or older, diagnosed with AF during the last 6months, and with at least one risk factor of thromboembolism based in the CHA2DS2-Vasc score are being selected. Demographic and clinical data will be collected during the visits to their usual clinic with a follow-up of 2years. The recruitment began on September 19, 2014, and the inclusion of the last patient is expected on September 18, 2016. According to the reported incidence of AF globally and taking into account the total Mexican population, the inclusion of 1,200 patients is estimated. CONCLUSIONS: The Atrial Fibrillation and Embolic Risk Registry (CARMEN-AF) will reveal the current status of thromboprophylaxis in patients with non-valvular AF, and will allow to get an overview of the national and international clinical practice guidelines accomplishment in this area.

Cuestionario de reacciones vasovagales a la donación de sangre en una institución de salud / Questionnaire of vasovagal reactions to blood donation in a health institution

Resumen: Objetivo: Identificar mediante un cuestionario de signos y síntomas vasovagales a donadores de sangre, con el fin de registrar los antecedentes que aumentan la probabilidad de presentar reacciones vasovagales. Materiales y Métodos: Se aplico un cuestionario a donadores de sangre, durante tres meses, en el banco de sangre en una institución de salud de tercer nivel. Resultados: El 100% de los donadores respondió negativamente a las preguntas del cuestionario, pero el 1.3% de ellos presentaron reacción vasovagal, siendo el mareo, palidez y náusea el signo y síntomas más frecuentemente mostrados. Al comparar dos grupos con y sin reacción vasovagal pareados por sexo, edad e índice de masa corporal, no hubo diferencias entre ellos. Conclusiones: Los donadores en nuestro país son fundamentalmente de reemplazo, por lo que se debe considerar esta circunstancia además de sus motivaciones, para el diseño de encuestas dirigidas a esta población.

Abstract: Objective: Identify, trough a vasovagal signs and symptoms questionnaire, blood donors in order to record the antecedents that increases the probability of presenting vasovagal reactions. Materials and Methods: A questionnaire was applied to blood donors, for three months, in the blood bank in a third-level health institution. Results: 100% of the donors answered negatively to the questions in the questionnaire, but 1.3% of them presented vasovagal reaction, with dizziness, pallor and nausea being the most frequently shown sing and symptoms. When comparing two groups with and without vasovagal reaction matched by sex, age and body mass index, there were no differences between them. Conclusions: Donors in our country are fundamentally replacement donors, so this circumstance plus their motivations should be considered for the design of surveys aimed at this population.

[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.

[Role of the sympathetic nervous system in vasovagal syncope and rationale for beta-blockers and norepinephrine transporter inhibitors]. / Papel del sistema nervioso simpático en el síncope vasovagal y justificación del uso de betabloqueadores e inhibidores del transportador de noradrenalina.

Vasovagal or neurocardiogenic syncope is a common clinical situation and, as with other entities associated with orthostatic intolerance, the underlying condition is a dysfunction of the autonomic nervous system. This article reviews various aspects of vasovagal syncope, including its relationship with orthostatic intolerance and the role of the autonomic nervous system in it. A brief history of the problem is given, as well as a description of how the names and associated concepts have evolved. The response of the sympathetic system to orthostatic stress, the physiology of the baroreflex system and the neurohumoral changes that occur with standing are analyzed. Evidence is presented of the involvement of the autonomic nervous system, including studies of heart rate variability, microneurography, cardiac innervation, and molecular genetic studies. Finally, we describe different studies on the use of beta-blockers and norepinephrine transporter inhibitors (sibutramine, reboxetine) and the rationality of their use to prevent this type of syncope.

El síncope vasovagal o neurocardiogénico es una situación clínica común, y así como en otras entidades asociadas con la intolerancia ortostática, la condición de base es una disfunción del sistema nervioso autónomo. En este artículo se revisan diversos aspectos sobre el síncope vasovagal, incluyendo su relación con la intolerancia ortostática y el papel que juega el sistema nervioso autónomo. Se da una breve reseña histórica del problema, así como una descripción de la forma en que han evolucionado los términos y conceptos asociados al mismo. Se hace un análisis sobre la respuesta del sistema nervioso simpático al estrés ortostático, la fisiología del sistema barorreflejo y los cambios neurohumorales que ocurren. Se muestra evidencia sobre el papel del sistema nervioso autónomo, incluyendo estudios sobre variabilidad de la frecuencia cardiaca, microneurografía, inervación cardiaca y estudios genéticos moleculares. Finalmente, se describen diferentes estudios sobre el uso de betabloqueadores e inhibidores del transportador de noradrenalina (sibutramina, reboxetina) y la justificación de su uso en la prevención de este tipo de síncope.

Hemodynamic profiles related to circulatory shock in cardiac care units / Perfiles hemodinámicos relacionados con el choque circulatorio en unidades de cuidados cardiacos

Abstract One-third of the population in intensive care units is in a state of circulatory shock, whose rapid recognition and mechanism differentiation are of great importance. The clinical context and physical examination are of great value, but in complex situations as in cardiac care units, it is mandatory the use of advanced hemodynamic monitorization devices, both to determine the main mechanism of shock, as to decide management and guide response to treatment, these devices include pulmonary flotation catheter as the gold standard, as well as more recent techniques including echocardiography and pulmonary ultrasound, among others. This article emphasizes the different shock mechanisms observed in the cardiac care units, with a proposal for approach and treatment.

Resumen Un tercio de la población de pacientes en unidades de cuidados intensivos se encuentran en choque circulatorio, el identificarlo y determinar su mecanismo de manera rápida y eficaz es de gran importancia. El contexto clínico y el examen físico son de gran utilidad, sin embargo existen situaciones de alta complejidad en las que se requiere del uso de las distintas modalidades de monitorización hemodinámica avanzada, tanto para determinar la causa, como para decidir el manejo y guiar respuesta al tratamiento, incluyendo el catéter de flotación pulmonar como gold standard, así como técnicas más recientes incluyendo ecocardiografía y ultrasonido pulmonar, entre otros. Este artículo enfatiza los distintos mecanismos de choque observados en las unidades de cuidados cardiacos, con propuesta de abordaje y tratamiento.

Extractos de los documentos de posicionamientos y recomendaciones mexicanas en enfermedades cardiovasculares y COVID-19 / Excerpts from the documents of Mexican positions and recommendations in cardiovascular diseases and COVID-19

Resumen 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.

Abstract 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.

[Electrocardiogram in channel disorders]. / El electrocardiograma en las canalopatías.

The ion channel diseases of the heart are a collection of genetically distinct arrhythmogenic cardiovascular disorders resulting from mutations in fundamental cardiac ion channels that orchestrate the action potential of the human heart. Our understanding of these genetic "channelopathies" has increased dramatically from electrocardiographic depictions of QT prolongations, ST-T alterations and torsades de pointes and clinical descriptions of people experiencing syncope and sudden death to molecular revelations of perfurbed ion channel genes. These exciting molecular breakthroughs have provided new opportunities for translational research with investigations into genotype-phenotype correlations and gene targeted therapies.

[Disclosure of "Brugada's syndrome" with intravenous propafenone]. / Desenmascaramiento del "síndrome de Brugada" con propafenona endovenosa.

We present the case of a woman with familial antecedents of a brother who died suddenly at the age of 39 years, and an other with Brugada syndrome. The ECG had not shown the typical pattern of the Brugada syndrome. Based on these antecedents, we decided to perform a pharmacological test with endovenous propafenone, which revealed the electrocardiographic alterations at 10 min after the administration. This is the first case in our knowledge in which endovenous propafenone manifested a concealed Brugada syndrome.

[Infrequent electrocardiographic changes during exercise stress test in a patient with Brugada's syndrome]. / Alteraciones electrocardiográficas infrecuentes durante la prueba de tolerancia al ejercicio en un paciente con síndrome de Brugada.

38 year old patient with a syncope history and family background of sudden death had an electrocardiogram compatible with the "Brugada Syndrome". When an exercise stress testing with Bruce protocol was done, we found that during the effort phase and at maximum effort, contrary to a ST segment normalization, a discreet increase of the ST segment elevation of 2 mm in V1 and V2 occurred. During recovery phase a decrease in the ST segment elevation was observed, at a normal level as before the test.