Empagliflozin's role in reducing ventricular repolarization heterogeneity: insights into cardiovascular mortality decline from the EMPATHY-HEART trial.

BACKGROUND: The incidence of myocardial infarction (MI) and sudden cardiac death (SCD) is significantly higher in individuals with Type 2 Diabetes Mellitus (T2DM) than in the general population. Strategies for the prevention of fatal arrhythmias are often insufficient, highlighting the need for additional non-invasive diagnostic tools. The T-wave heterogeneity (TWH) index measures variations in ventricular repolarization and has emerged as a promising predictor for severe ventricular arrhythmias. Although the EMPA-REG trial reported reduced cardiovascular mortality with empagliflozin, the underlying mechanisms remain unclear. This study investigates the potential of empagliflozin in mitigating cardiac electrical instability in patients with T2DM and coronary heart disease (CHD) by examining changes in TWH. METHODS: Participants were adult outpatients with T2DM and CHD who exhibited TWH > 80 µV at baseline. They received a 25 mg daily dose of empagliflozin and were evaluated clinically including electrocardiogram (ECG) measurements at baseline and after 4 weeks. TWH was computed from leads V4, V5, and V6 using a validated technique. The primary study outcome was a significant (p < 0.05) change in TWH following empagliflozin administration. RESULTS: An initial review of 6,000 medical records pinpointed 800 patients for TWH evaluation. Of these, 412 exhibited TWH above 80 µV, with 97 completing clinical assessments and 90 meeting the criteria for high cardiovascular risk enrollment. Empagliflozin adherence exceeded 80%, resulting in notable reductions in blood pressure without affecting heart rate. Side effects were generally mild, with 13.3% experiencing Level 1 hypoglycemia, alongside infrequent urinary and genital infections. The treatment consistently reduced mean TWH from 116 to 103 µV (p = 0.01). CONCLUSIONS: The EMPATHY-HEART trial preliminarily suggests that empagliflozin decreases heterogeneity in ventricular repolarization among patients with T2DM and CHD. This reduction in TWH may provide insight into the mechanism behind the decreased cardiovascular mortality observed in previous trials, potentially offering a therapeutic pathway to mitigate the risk of severe arrhythmias in this population. TRIAL REGISTRATION: NCT: 04117763.

ST segment and T wave abnormalities: A narrative review.

INTRODUCTION: The electrocardiogram (ECG) is a valuable tool for interpreting ventricular repolarization. This article aims to broaden the diagnostic scope beyond the conventional ischemia-centric approach, integrating an understanding of pathophisiological influences on ST-T wave changes. METHODS: A review was conducted on the physiological underpinnings of ventricular repolarization and the pathophisiological processes that can change ECG patterns. The research encompassed primary repolarization abnormalities due to uniform variations in ventricular action potential, secondary changes from electrical or mechanical alterations, and non-ischemic conditions influencing ST-T segments. RESULTS: Primary T waves are characterized by symmetrical waves with broad bases and variable QT intervals, indicative of direct myocardial action potential modifications due to ischemia, electrolyte imbalances, and channelopathies. Secondary T waves are asymmetric and often unassociated with significant QT interval changes, suggesting depolarization alterations or changes in cardiac geometry and contractility. CONCLUSION: We advocate for a unified ECG analysis, recognizing primary and secondary ST-T changes, and their clinical implications. Our proposed analytical framework enhances the clinician's ability to discern a wide array of cardiac conditions, extending diagnostic accuracy beyond myocardial ischemia.

Sodium overload during postnatal phases impairs diastolic function and exacerbates reperfusion arrhythmias in adult rats.

Sodium overload during childhood impairs baroreflex sensitivity and increases arterial blood pressure and heart rate in adulthood; these effects persist even after high-salt diet (HSD) withdrawal. However, the literature lacks details on the effects of HSD during postnatal phases on cardiac ischemia/reperfusion responses in adulthood. The current study aimed to elucidate the impact of HSD during infancy adolescence on isolated heart function and cardiac ischemia/reperfusion responses in adulthood. Male 21-day-old Wistar rats were treated for 60 days with hypertonic saline solution (NaCl; 0.3M; experimental group) or tap water (control group). Subsequently, both groups were maintained on a normal sodium diet for 30 days. Subsequently, the rats were euthanized, and their hearts were isolated and perfused according to the Langendorff technique. After 30 min of the basal period, the hearts were subjected to 20 min of anoxia, followed by 20 min of reperfusion. The basal contractile function was unaffected by HSD. However, HSD elevated the left ventricular end-diastolic pressure during reperfusion (23.1 ± 5.2 mmHg vs. 11.6 ± 1.4 mmHg; p < 0.05) and increased ectopic incidence period during reperfusion (208.8 ± 32.9s vs. 75.0 ± 7.8s; p < 0.05). In conclusion, sodium overload compromises cardiac function after reperfusion events, diminishes ventricular relaxation, and increases the severity of arrhythmias, suggesting a possible arrhythmogenic effect of HSD in the postnatal phases.

Chagas Cardiomyopathy and Myocardial Sympathetic Denervation.

PURPOSE OF REVIEW: More than a century since its discovery, the pathogenesis of Chagas heart disease (CHD) remains incompletely understood. The role of derangements in the autonomic control of the heart in triggering malignant arrhythmia before the appearance of contractile ventricular impairment was reviewed. RECENT FINDINGS: Although previous investigations had demonstrated the anatomical and functional consequences of parasympathetic dysautonomia upon the heart rate control, only recently, coronary microvascular disturbances and sympathetic denervation at the ventricular level have been reported in patients and experimental models of CHD, exploring with nuclear medicine methods their impact on the progression of myocardial dysfunction and cardiac arrhythmias. More important than parasympathetic impaired sinus node regulation, recent evidence indicates that myocardial sympathetic denervation associated with coronary microvascular derangements is causally related to myocardial injury and arrhythmia in CHD. Additionally, 123I-MIBG imaging is a promising tool for risk stratification of progression of ventricular dysfunction and sudden death.

The Role of the Immune System on the Cardiac Complications Observed in SARS-CoV-2

Abstract An acute respiratory syndrome caused by SARS-CoV2 was declared a pandemic by the World Health Organization. Current data in the world and in Brazil show that approximately 40% of patients who died have some type of cardiac comorbidity. There are also robust reports showing an increase in IL-6 / IL-1B / TNF-alpha and the presence of lymphopenia in patients with COVID-19. Our team and others have shown that increased cytokines are the link between arrhythmias/Left ventricular dysfunction and the immune system in different diseases. In addition, it has been well demonstrated that lymphopenia can not only be a good marker, but also a factor that causes heart failure. Thus, the present review focused on the role of the immune system upon the cardiac alterations observed in the SARS-CoV2 infection. Additionally, it was well described that SARS-CoV-2 is able to infect cardiac cells. Therefore, here it will be reviewed in deep.

In Vivo Cardiotoxic Potential of Micrurus frontalis Venom.

In the present study, we investigated the cardiotoxic potential of Micrurus frontalis venom. Twelve guinea pigs (Cavia porcellus) were distributed in two groups (n = 6), named control and envenomed. Control groups received 0.2 ml of PBS/BSA, while envenomed group received 0.2 ml of the same solution containing 450 µg/kg of M. frontalis venom. Both were intramuscular injections. Electrocardiography, echocardiogram, blood count, and serum biochemistry were performed before and 2 h after inoculation. Necropsy was performed, and histological and ultrastructural analysis of the heart were conducted. First clinical signs were presented as early as 18 min after venom inoculation. All poisoned animals presented flaccid paralysis of both hind and forelimbs, followed by fasciculations and respiratory arrythmia. However, the animals did not die in the first 2 h of poisoning. ECG of the poisoned animals revealed severe ventricular arrythmias, corroborated by reduction of both ejection and shortening fractions, increase in CK, CK-MB, troponin, cardiomyocyte degeneration, fragmentation and mitochondrial damage. M. frontalis venom causes severe heart damage, eliciting both morphological and arrhythmogenic effects after only 2 h of envenomation.

CaMKII activation in early diabetic hearts induces altered sarcoplasmic reticulum-mitochondria signaling.

Prediabetic myocardium, induced by fructose-rich diet (FRD), is prone to increased sarcoplasmic reticulum (SR)-Ca2+ leak and arrhythmias due to increased activity of the Ca2+/calmodulin protein kinase II (CaMKII). However, little is known about the role of SR-mitochondria microdomains, mitochondrial structure, and mitochondrial metabolisms. To address this knowledge gap we measured SR-mitochondrial proximity, intracellular Ca2+, and mitochondrial metabolism in wild type (WT) and AC3-I transgenic mice, with myocardial-targeted CaMKII inhibition, fed with control diet (CD) or with FRD. Confocal images showed significantly increased spontaneous Ca2+ release events in FRD vs. CD WT cardiomyocytes. [3H]-Ryanodine binding assay revealed higher [3H]Ry binding in FRD than CD WT hearts. O2 consumption at State 4 and hydrogen peroxide (H2O2) production rate were increased, while respiratory control rate (RCR) and Ca2+ retention capacity (CRC) were decreased in FRD vs. CD WT isolated mitochondria. Transmission Electron Microscopy (TEM) images showed increased proximity at the SR-mitochondria microdomains, associated with increased tethering proteins, Mfn2, Grp75, and VDAC in FRD vs. CD WT. Mitochondria diameter was decrease and roundness and density were increased in FRD vs. CD WT specimens. The fission protein, Drp1 was significantly increased while the fusion protein, Opa1 was unchanged in FRD vs. CD WT hearts. These differences were prevented in AC3-I mice. We conclude that SR-mitochondria microdomains are subject to CaMKII-dependent remodeling, involving SR-Ca2+ leak and mitochondria fission, in prediabetic mice induced by FRD. We speculate that CaMKII hyperactivity induces SR-Ca2+ leak by RyR2 activation which in turn increases mitochondria Ca2+ content due to the enhanced SR-mitochondria tethering, decreasing CRC.

Atrial proarrhythmic effect of lead as one of the PM10 metal components of air pollution. An in-silico study.

Particulate matter (PM) is considered the most severe environmental pollution problem due to its serious effects on human health associated with an increased risk of cardiovascular morbidity and mortality. In this work, a physicochemical characterization of PM10 from the city of Medellin was developed. The results evince that lead (Pb) is one of the most abundant elements since it is present in all analyzed samples. Therefore, Pb was chosen to perform an in-silico study to assess its effects on atrial arrhythmias generation. For this purpose, we developed a model representing the Pb2+ blocking effect on the L-type calcium channel. This formulation was incorporated in a human atrial cell mathematical model and in 2D and 3D models of human atria. The simulations showed a proarrhythmic effect at high Pb2+ concentrations, through shortening of action potential duration inducing the generation of reentrant activity and atrial flutter. The results contribute to the knowledge about the cardiac physiopathological processes, triggered by lead as one of the main PM10 metal components of air pollution, that yields the generation of arrhythmias.

Eugenol interacts with cardiac sodium channel and reduces heart excitability and arrhythmias.

AIMS: Eugenol is a natural compound found in the essential oils of many aromatic plants. The compound is used as a local anesthetic because of its inhibitory effect on the voltage-gated Na+ channels (Nav), which are expressed in the nociceptive neurons. Eugenol has shown wide range of activities in the cardiovascular system; most of these activities are attributed to the modulation of voltage-sensitive Ca2+ channels. However, its action on Nav1.5, the main subtype of Nav expressed in the mammalian myocardium, is unknown. The interaction of eugenol with Nav1.5 could also contribute to its antiarrhythmic properties in vitro and ex vivo. We investigated the compound's effect on sodium current (INa) and its possible cardiac antiarrhythmic activity. METHODS: The effect of eugenol on cardiac contractility was investigated using isolated atrium from guinea pig (for isometric force measurements). The compound's effect on INa was evaluated using human embryonic cell transiently expressing human Nav1.5 and patch-clamp technique. KEY FINDINGS: Eugenol caused negative inotropic and chronotropic effects in the atria. In the ex vivo arrhythmia model, eugenol decreased atrial pacing disturbance induced by ouabain. Eugenol reduced the INa in a concentration-dependent manner. Furthermore, the compound left-shifted the stationary inactivation curve, delayed recovery from inactivation of the INa, and preferentially blocked the channel in the inactivated state. Importantly, eugenol was able to attenuate the late sodium current. All these aspects are considered to be antiarrhythmic. SIGNIFICANCE: Overall, our findings demonstrate that eugenol has antiarrhythmic activity due, at least in part, to its interaction with Nav1.5.

Latin-American Registry of Cardiovascular Disease and COVID-19: Rationale and Design of the CARDIO COVID 19-20 Registry.

Background: Infection caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) exhibits a strong infectivity but less virulence compared to severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS). In terms of cardiovascular morbidity, susceptible population include elderly and patients with certain cardiovascular conditions. This infection has been associated with cardiac injury, cardiovascular complications and higher mortality. Objectives: The main objective of the CARDIO COVID 19-20 Registry is to determine the presence of cardiovascular comorbidities and cardiovascular complications in COVID-19 infected patients that required in-hospital treatment in different Latin American institutions. Methods: The CARDIO COVID 19-20 Registry is an observational, multicenter, ambispective, and hospital-based registry of patients with confirmed COVID-19 infection who required in-hospital treatment in Latin America. Enrollment of patients started on May 01, 2020 and was initially planned to last three months; based on the progression of pandemic in Latin America, enrollment was extended until December 2020, and could be extended once again based on the pandemic course in our continent at that moment. Conclusions: The CARDIO COVID 19-20 Registry will characterize the in-hospital population diagnosed with COVID-19 in Latin America in order to identify risk factors for worsening of cardiovascular comorbidities or for the appearance of cardiovascular complications during hospitalization and during the 30-day follow up period.

Cardiotoxic Effects of Micrurus surinamensis (Cuvier, 1817) Snake Venom.

Micrurus surinamensis is a coral snake from the Elapidae family of wide distribution in Amazonia Forest. Its venom contains neurotoxins that induce muscular and respiratory paralysis; however, its cardiovascular action is not yet characterized. The aim of this study was to investigate the cardiotoxic effects caused by M. surinamensis poisoning in rodents. Twelve guinea pigs (Cavia porcellus) were distributed in two groups (n = 6) named as control and envenomed. The control group received 0.2 ml of PBS/BSA via intramuscular injection (IM), while envenomed animals received 0.75 µg of venom per g of body weight, also via IM. Electrocardiographic examination (ECG) and biochemical serum tests were conducted before and 2 h after inoculation. ECG of the envenomed animals revealed severe progressive arrhythmias including atrioventricular block, supraventricular, and ventricular extrasystoles. Serum biochemistry showed significant increase in CK, CK-MB, and LDH enzymes corroborating the skeletal and cardiac muscle damage. Myonecrosis and degeneration were observed in both skeletal and heart muscle; nevertheless, transmission electron microscopy revealed cardiac muscle fibers fragmentation. In conclusion, M. surinamensis venom has a potent cardiotoxic activity eliciting arrhythmogenic effects and heart damage after only 2 h of envenomation.

[Peri-ictal electrocardiographic alterations in paediatric epilepsy patients. A prospective study]. / Alteraciones electrocardiográficas periictales en pacientes pediátricos con epilepsia. Un estudio prospectivo.

INTRODUCTION: Epileptic seizures can be associated with peri-ictal heart rhythm disorders and even sudden death (SUDEP). Few paediatric studies have been conducted on the subject. AIM: To determine heart rhythm disorders in paediatric patients with epilepsy who were studied with video-electroencephalogram (video-EEG). METHODS: Prospective, observational study in patients under 18 years of age admitted for video-EEG at the Hospital Clinico Red de Salud UC-Christus, Santiago, Chile. A neurological and cardiological evaluation and electrocardiogram (ECG) were performed, in addition to a Holter ECG simultaneously with the video-EEG. RESULTS: Twenty-five patients were studied, 12 with refractory epilepsies, 23/25 focal and 20 on polytherapy. Altogether 768 hours of video-EEG were recorded, including 281 seizures in 15 patients: 157 clinical and 103 generalised. There were no serious arrhythmias, only non-specific or probably benign disorders, mainly incomplete right bundle branch block in 11 patients, which were more frequent in refractory epilepsies (p<0.036). Heart rate variation occurred mainly in seizures >30 seconds. No patient presented SUDEP. CONCLUSIONS: This is the first prospective study, with a new technique, using video-EEG and Holter ECG simultaneously in paediatrics. Despite the high number of seizures and refractory patients, we found no serious heart rhythm disorders, consistent with the clinical evaluation. Right bundle branch block is considered a non-pathological cardiological finding, but was highly prevalent in our sample compared to the normal population, especially in refractory epilepsy. Given that this is a serious event in epilepsy, it is important to further investigate such studies to assess preventive measures.

TITLE: Alteraciones electrocardiográficas periictales en pacientes pediátricos con epilepsia. Un estudio prospectivo.Introducción. Las crisis epilépticas pueden asociarse a alteraciones del ritmo cardíaco periictales e incluso a muerte súbita (SUDEP). Existen escasos estudios pediátricos al respecto. Objetivo. Determinar las alteraciones del ritmo cardíaco en pacientes pediátricos con epilepsia estudiados con videoelectroencefalograma (video-EEG). Métodos. Estudio prospectivo, observacional, en pacientes menores de 18 años ingresados para video-EEG en el Hospital Clínico Red de Salud UC-Christus, Santiago, Chile. Se realizó una evaluación neurológica y cardiológica, electrocardiograma (ECG) y Holter ECG simultáneo al video-EEG. Resultados. Se estudió a 25 pacientes, 12 con epilepsias refractarias, 23/25 focales y 20 en tratamiento con politerapia. Se registraron 768 horas de video-EEG, incluyendo 281 crisis epilépticas en 15 pacientes: 157 clínicas y 103 generalizadas. No hubo arritmias graves; sólo alteraciones inespecíficas o probablemente benignas, principalmente bloqueo incompleto de la rama derecha en 11 pacientes, más frecuente en las epilepsias refractarias (p menor de 0,036). La variación de la frecuencia cardíaca ocurrió principalmente en crisis > 30 segundos. Ningún paciente ha presentado SUDEP. Conclusiones. Éste es el primer estudio prospectivo, con una nueva técnica, usando simultáneamente video-EEG y Holter ECG en pediatría. Pese al alto número de crisis y pacientes refractarios, no encontramos alteraciones graves del ritmo cardíaco, en concordancia con la evaluación clínica. El bloqueo de la rama derecha se considera un hallazgo cardiológico no patológico, pero tuvo una alta prevalencia en nuestra muestra, comparada con la población normal, especialmente en la epilepsia refractaria. Dado que la SUDEP es un evento grave en la epilepsia, es importante ahondar más en este tipo de estudios para evaluar medidas preventivas.

Paraquat herbicide diminishes chemoreflex sensitivity, induces cardiac autonomic imbalance and impair cardiac function in rats.

Paraquat (PQT) herbicide is widely used in agricultural practices despite being highly toxic to humans. It has been proposed that PQT exposure may promote cardiorespiratory impairment. However, the physiological mechanisms involved in cardiorespiratory dysfunction following PQT exposure are poorly known. We aimed to determine the effects of PQT on ventilatory chemoreflex control, cardiac autonomic control, and cardiac function in rats. Male Sprague-Dawley rats received two injections/week of PQT (5 mg·kg-1 ip) for 4 wk. Cardiac function was assessed through echocardiography and pressure-volume loops. Ventilatory function was evaluated using whole body plethysmography. Autonomic control was indirectly evaluated by heart rate variability (HRV). Cardiac electrophysiology (EKG) and exercise capacity were also measured. Four weeks of PQT administration markedly enlarged the heart as evidenced by increases in ventricular volumes and induced cardiac diastolic dysfunction. Indeed, end-diastolic pressure was significantly higher in PQT rats compared with control (2.42 ± 0.90 vs. 4.01 ± 0.92 mmHg, PQT vs. control, P < 0.05). In addition, PQT significantly reduced both the hypercapnic and hypoxic ventilatory chemoreflex response and induced irregular breathing. Also, PQT induced autonomic imbalance and reductions in the amplitude of EKG waves. Finally, PQT administration impaired exercise capacity in rats as evidenced by a ∼2-fold decrease in times-to-fatigue compared with control rats. Our results showed that 4 wk of PQT treatment induces cardiorespiratory dysfunction in rats and suggests that repetitive exposure to PQT may induce harmful mid/long-term cardiovascular, respiratory, and cardiac consequences.NEW & NOREWORTHY Paraquat herbicide is still employed in agricultural practices in several countries. Here, we showed for the first time that 1 mo paraquat administration results in cardiac adverse remodeling, blunts ventilatory chemoreflex drive, and promotes irregular breathing at rest in previously healthy rats. In addition, paraquat exposure induced cardiac autonomic imbalance and cardiac electrophysiology alterations. Lastly, cardiac diastolic dysfunction was overt in rats following 1 mo of paraquat treatment.

NOD Mice Recapitulate the Cardiac Disturbances Observed in Type 1 Diabetes.

This work aimed at testing the hypothesis that NOD/ShiLtJ mice (NOD) recapitulate the cardiac disturbances observed on type 1 diabetes (T1D). NOD mice were studied 4 weeks after the onset of hyperglycemia, and NOR/Lt mice matched as control. Cardiac function was evaluated by echocardiography and electrocardiography (ECG). Action potentials (AP) and Ca2+ transients were evaluated at whole heart level. Heart mitochondrial function was evaluated by high-resolution respirometry and H2O2 release. NOD mice presented a reduction in hearth weight. Mitochondrial oxygen fluxes and H2O2 release were similar between NOD and NOR mice. ECG revealed a QJ interval prolongation in NOD mice. Furthermore, AP duration at 30% of repolarization was increased, and it depicted slower Ca2+ transient kinetics. NOD mice presented greater number/severity of ventricular arrhythmias both in vivo and in vitro. In conclusion, NOD mice evoked cardiac electrical and calcium handling disturbances similar to the observed in T1D. Graphical Abstract .

Electrocardiographic Changes in Children with Multisystem Inflammation Associated with COVID-19: Associated with Coronavirus Disease 2019.

OBJECTIVE: To analyze findings and trends on serial electrocardiograms (ECGs) in multisystem inflammatory syndrome in children (MIS-C) associated with coronavirus disease taken during the course of illness and at follow-up. STUDY DESIGN: We included all children presenting with MIS-C at a single center with 3 or more ECGs taken during the course of their illness. We measured ECG intervals (PR, QRSd, and QTc) and amplitudes (R-, S-, and T-waves) on each ECG and documented any arrhythmias and ST-segment changes. RESULTS: A majority of children (n = 42, 67%) showed ECG changes. The most common findings were low QRS amplitudes and transient T-wave inversion. ST changes were uncommon and included ST-segment elevation consistent with pericarditis in 1 child and acute coronary ischemia in 1 child. Arrhythmias were seen in 13 children (21%) but were benign with the exception of 1 child who was compromised by an atrial tachycardia requiring support with extracorporeal membrane oxygenation. No children were found to have high-grade atrioventricular block. CONCLUSIONS: MIS-C is associated with electrocardiographic changes over the course of the illness, with low amplitude ECGs on presentation, followed by transient T-wave inversion, particularly in the precordial leads. There was a low prevalence of ST-segment changes and tachyarrhythmias.

Cardiac arrhythmias in highlanders with a diagnosis of chronic cor pulmonale. / Arritmias cardíacas en habitantes de gran altura con diagnóstico de corazón pulmonar crónico.

Antecedentes: El corazón pulmonar crónico (CPC) muestra un incremento en habitantes que viven en grandes altitudes. Objetivo: Investigar la frecuencia de arritmias cardíacas y factores de riesgo para su desarrollo. Métodos: Estudio descriptivo y transversal; se revisó el registro de pacientes internados del Departamento de Cardiología del Instituto Nacional de Tórax, La Paz, Bolivia, entre enero de 2017 y junio de 2018; se incorporó a todos los individuos con diagnóstico de CPC, definido por criterios clínicos, electrocardiográficos y ecocardiográficos; se incluyó a 162 pacientes que cumplieron los criterios en el análisis; se utilizaron la t de Student y ANOVA. Resultados: Arritmias: fibrilación auricular (FA), 125 (75%); aleteo auricular (AA), 17 (10.5%); taquicardia auricular (TA), 17 (10.5%); extrasístoles, 3 (1.9%). Según el análisis univariado, los factores relacionados con el desarrollo de arritmias fueron: eritrocitosis: FA, RR: 1.33, otras arritmias (RR: 1.67), p = 0.0001; hipertensión arterial pulmonar: FA, RR: 3.10, otras arritmias (RR: 3.21), p = 0.0001; dilatación de aurícula derecha (AD): FA, RR: 1.92, otras arritmias (RR: 2.13), p = 0.0001; obesidad: FA, RR: 3.47, p = 0.001, otras arritmias (RR: 3.70), p = 0.001; hipertensión arterial sistémica: FA, RR: 3.10, p = 0.001, otras arritmias (RR: 3.21), p = 0.001. Según el análisis multivariado: eritrocitosis (RR: 2.2), dilatación de AD (RR: 1.2), p = 0.0001. Conclusiones: Se encontró FA con mayor frecuencia en los pacientes con CPC; los factores de riesgo con mayor significancia estadística para su presentación fueron la eritrocitosis y la dilatación de la AD. Background: Chronic cor pulmonale (CPC), with increased presentation in high-altitude inhabitants. Objectives: Investigating the frequency of cardiac arrhythmias, and risk factors for its development. Methods: Descriptive, cross-sectional study, the inpatient registry of the Department of Cardiology of the National Institute of Torax, La Paz-Bolivia, from January 2017 to June 2018 was reviewed, all were incorporated with the diagnosis of CPC, defined by clinical criteria, electrocardiographic and echocardiographic, 162 patients who met the criteria were taken, the student's t-test and ANOVA were used for the analysis. Results: Arrhythmias: atrial fibrillation (AF) 125 (75%), atrial flutter (AA) 17 (10.5%), atrial tachycardia (AT) 17 (10.5%), extrasystoles 3 (1.9%). Univariate analysis of factors related to the development of arrhythmias: erythrocytosis: FA, RR: 1.33, other arrhythmias RR: 1.67, p = 0.0001, pulmonary arterial hypertension: FA, RR: 3.10, other arrhythmias RR: 3.21, p = 0.0001, right atrial dilation (AD): FA, RR: 1.92, other arrhythmias RR: 2.13, p = 0.0001, obesity: FA, RR: 3.47, p = 0.001, other arrhythmias RR: 3.70, p = 0.001, systemic arterial hypertension: FA: RR: 3.10, p = 0.001, other arrhythmias RR: 3.21, p = 0.001. Multivariate analysis: erythrocytosis (RR: 2.2), AD dilation (RR: 1.2), p = 0.0001. Conclusions: AF was found more frequently in patients with CPC, the risk factors with the greatest statistical significance for presentation were: erythrocytosis and AD dilation.

Arritmias cardíacas en habitantes de gran altura con diagnóstico de corazón pulmonar crónico / Cardiac arrhythmias in highlanders with a diagnosis of chronic cor pulmonale

Resumen Antecedentes: El corazón pulmonar crónico (CPC) muestra un incremento en habitantes que viven en grandes altitudes. Objetivo: Investigar la frecuencia de arritmias cardíacas y factores de riesgo para su desarrollo. Métodos: Estudio descriptivo y transversal; se revisó el registro de pacientes internados del Departamento de Cardiología del Instituto Nacional de Tórax, La Paz, Bolivia, entre enero de 2017 y junio de 2018; se incorporó a todos los individuos con diagnóstico de CPC, definido por criterios clínicos, electrocardiográficos y ecocardiográficos; se incluyó a 162 pacientes que cumplieron los criterios en el análisis; se utilizaron la t de Student y ANOVA. Resultados: Arritmias: fibrilación auricular (FA), 125 (75%); aleteo auricular (AA), 17 (10.5%); taquicardia auricular (TA), 17 (10.5%); extrasístoles, 3 (1.9%). Según el análisis univariado, los factores relacionados con el desarrollo de arritmias fueron: eritrocitosis: FA, RR: 1.33, otras arritmias (RR: 1.67), p = 0.0001; hipertensión arterial pulmonar: FA, RR: 3.10, otras arritmias (RR: 3.21), p = 0.0001; dilatación de aurícula derecha (AD): FA, RR: 1.92, otras arritmias (RR: 2.13), p = 0.0001; obesidad: FA, RR: 3.47, p = 0.001, otras arritmias (RR: 3.70), p = 0.001; hipertensión arterial sistémica: FA, RR: 3.10, p = 0.001, otras arritmias (RR: 3.21), p = 0.001. Según el análisis multivariado: eritrocitosis (RR: 2.2), dilatación de AD (RR: 1.2), p = 0.0001. Conclusiones: Se encontró FA con mayor frecuencia en los pacientes con CPC; los factores de riesgo con mayor significancia estadística para su presentación fueron la eritrocitosis y la dilatación de la AD.

Abstract Background: Chronic cor pulmonale (CPC), with increased presentation in high-altitude inhabitants. Objectives: Investigating the frequency of cardiac arrhythmias, and risk factors for its development. Methods: Descriptive, cross-sectional study, the inpatient registry of the Department of Cardiology of the National Institute of Torax, La Paz-Bolivia, from January 2017 to June 2018 was reviewed, all were incorporated with the diagnosis of CPC, defined by clinical criteria, electrocardiographic and echocardiographic, 162 patients who met the criteria were taken, the student's t-test and ANOVA were used for the analysis. Results: Arrhythmias: atrial fibrillation (AF) 125 (75%), atrial flutter (AA) 17 (10.5%), atrial tachycardia (AT) 17 (10.5%), extrasystoles 3 (1.9%). Univariate analysis of factors related to the development of arrhythmias: erythrocytosis: FA, RR: 1.33, other arrhythmias RR: 1.67, p = 0.0001, pulmonary arterial hypertension: FA, RR: 3.10, other arrhythmias RR: 3.21, p = 0.0001, right atrial dilation (AD): FA, RR: 1.92, other arrhythmias RR: 2.13, p = 0.0001, obesity: FA, RR: 3.47, p = 0.001, other arrhythmias RR: 3.70, p = 0.001, systemic arterial hypertension: FA: RR: 3.10, p = 0.001, other arrhythmias RR: 3.21, p = 0.001. Multivariate analysis: erythrocytosis (RR: 2.2), AD dilation (RR: 1.2), p = 0.0001. Conclusions: AF was found more frequently in patients with CPC, the risk factors with the greatest statistical significance for presentation were: erythrocytosis and AD dilation.

Evaluación y validación diagnóstica de las variables iQT, razón iQTRR, razón iRTRR para el diagnóstico DEQTc prolongado / Validation of iQT, iQTRR, iRT/RR ratio for estimation of QTc

ANTECEDENTES: El intervalo QT representa la despolarización y repolarización ventricular y su prolongación está asociada a un mayor riesgo de arritmias graves y muerte súbita. Depende de la frecuencia cardíaca y su rápida valoración es difícil de obtener en la práctica clínica. Una forma que facilita este proceso es medir sólo el intervalo QT pero este no siempre se relaciona con un intervalo QTc prolongado. Debido a esto, se postula que una variable compuesta debería tener mejor rendimiento diagnóstico para este objetivo. OBJETIVO: Describir la correlación de 3 variables electrocardiográficas; intervalo QT (iQT), razón del intervalo QT intervalo RR (%iQTRR) y razón del intervalo RT intervalo RR (%iRTRR), en relación a la variable QT corregido (iQTc). Se efectuó una evaluación diagnóstica y validación de las variables mencionadas para establecer el diagnóstico de intervalo QT largo y las propiedades diagnósticas de las mismas para el diagnóstico de iQTc prolongado según la fórmula Bazett. METODOS Y RESULTADOS: Se efectuó un estudio transversal descriptivo-relacional, usando una muestra no probabilística formada por 220 electrocardiogramas registrados en la base de datos del centro cardiovascular. Las mediciones provenían de ECGs registrados en reposo con medición con cáliper de los intervalos QT y RR en derivadas D2 y/o V5, expresadas en milisegundos. Se excluyó la presencia de isquemia, preexcitación y repolarización precoz. Se obtuvo como resultado que la variable razón iQTRR tiene mejor correlación, concordancia, sensibilidad y valor predictivo negativo para el diagnóstico del iQTc prolongado, versus las variables iQT y razón iRTRR, principalmente en mujeres. CONCLUSIONES: La variable razón iQTRR tiene una mejor correlación, concordancia, sensibilidad y valor predictivo negativo (VPN) para el diagnóstico del iQTc prolongado, comparado con las variables iQT y razón iRTRR, principalmente, en mujeres. Utilizando ambas variables este efecto se potencia y permite concluir que si una mujer tiene un iQT observado <470 ms, y una razón QTRR< 47,5%, esto se corresponde con un intervalo QTc normal, con un VPN de 100% .

BACKGROUND: The QT interval (QT) includes depolarization and repolarization phases of cardiac cycle. Its prolongation is associated to an increa sed risk of serious arrhythmia and sudden death. QT depends on heart rate and it is usually corrected using the Bazett formula (QTc). Prolonged QT is not usually well related to QTc. We postulate that a composite formula muy have a greater value for predicting serious arrhythmia. AIM: To correlate the predictive value of a different approach to estimate a corrected QT interval: the ratio of RT to RR intervals (QT/RR, expressed as a percentage METHODS and RESULTS: A non probabilistic sample of 220 ECGs were obtained from our data base. ECGs were recorded at rest and measurements were performed in leads Ds and/or V5 using zetcalipers, the values being expressed in ms. The presence of ischemia, pre excitation and early repolarization were excluded. The QT/RR ratio showed better correlation, concordance, sensitivity, and negative predicted value with the usual QTc interval compared to QT alone or de RT/RR ratio, especially so in women.

Translational Approach for Percutaneous Interventions for the Treatment of Cardiac Arrhythmias

Abstract New translational concepts on cellular and tissue substrate of cardiac arrhythmias have been responsible for the development of non-pharmacological interventions, with important achievements compared to the conventional approach with antiarrhythmic drugs. In addition, the increasing knowledge of anatomical and electrophysiological studies, sophisticated mapping methods, special catheters, and controlled clinical trials have favored the progression of ablation of tachyarrhythmias, particularly of ventricular tachyarrhythmias and atrial fibrillation.

Permanent His Bundle Pacing Implantation Facilitated by Visualization of the Tricuspid Valve Annulus.

BACKGROUND: His bundle pacing (HBP) is the most physiological pacing modality. However, HBP has longer procedure times with frequent high capture thresholds, which likely contributes to the low adoption of this approach. The aim of this study is to compare HBP implantation with a novel imaging technique versus the standard implantation technique. METHODS: This study included 50 patients with standard pacing indications randomized to HBP with visualization of the tricuspid valve annulus (N=25, the visualization group) or with the standard method (N=25, the control group). In the visualization group, the tricuspid valve annulus was imaged by contrast injection in the right ventricle during fluoroscopy. The site for HBP was identified in relationship to the tricuspid septal leaflet and interventricular septum. RESULTS: Permanent HBP was successful in 92% in the visualization group and 88% in the control group. The fluoroscopic time for HBP lead placement was significantly shorter in the visualization group (7.1±3.3 minutes) compared with the control group (10.1±5.6 minutes, P=0.03). Total procedural and fluoroscopic times were also significantly shorter in the visualization group (91.0±15.7 and 9.6±3.8 minutes) than the control group (104.4±17.8 and 12.7±6.2 minutes, P=0.01 and 0.04, respectively). There was no significant difference in capture threshold between groups. In the visualization group, there was a quantitative association between the HBP site and the tricuspid valve annulus. CONCLUSIONS: The visualization technique shortens the procedural and fluoroscopic times for HBP implantation. Moreover, anatomic localization of HBP sites is strongly associated with physiological characteristics of pacing, which can help guide optimal lead placement. Registration: URL: https://www.chictr.org.cn/index.aspx. Unique identifier: ChiCTR2000029834.