Síndrome de QT largo congénito y bradicardia fetal: la importancia del diagnóstico / Congenital long QT syndrome and fetal bradycardia: the importance of the diagnosis

Antecedentes: El síndrome de QT largo es una canalopatía que afecta a la repolarización ventricular y aumenta el riesgo de sufrir arritmias ventriculares graves. Puede ser congénito o adquirido, y es una causa conocida de muerte súbita. Caso clínico: Gestante primigesta, de 28 años, sin antecedentes de interés. En ecografías prenatales se objetivó en el feto bradicardia sinusal mantenida desde la semana 28, sin repercusión hemodinámica, que persistió hasta la finalización de la gestación (semana 37+3). Al nacimiento se realizaron electrocardiogramas seriados que mostraron alteraciones en la repolarización con alargamiento del intervalo QT corregido. Se realizó estudio genético que confirmó síndrome de QT largo tipo 1 y se inició tratamiento oral con beta-bloqueantes, con buena respuesta. Conclusiones: El síndrome de QT largo suele diagnosticarse posnatalmente. Es importante conocer sus características clínicas prenatales para poder establecer un diagnóstico precoz y minimizar así el riesgo de muerte súbita de estos pacientes.

Background: Long QT syndrome is a channelopathy that affects ventricular repolarization and increases the risk of severe ventricular arrhythmias. It can be congenital or acquired, and is a known cause of sudden cardiac death. Case report: A 28-year-old primigravida with no significant medical history. Prenatal ultrasounds revealed sustained fetal sinus bradycardia from week 28, without hemodynamic repercussion, which persisted until the end of gestation (at 37+3 weeks). Serial electrocardiograms were performed after birth, showing repolarization abnormalities with prolonged corrected QT interval. A genetic study confirmed long QT syndrome type 1, and oral treatment with beta-blockers was initiated, showing a positive response. Conclusions: Long QT syndrome is often diagnosed postnatally. It is important to be aware of his prenatal clinical features in order to establish an early diagnosis and minimize the risk of sudden death in these patients.

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.

Assessment of QT Interval Abnormalities on Electrocardiogram in Children With Breath-Holding Spells

Objective: To assess QT interval abnormalities among children with breath-holding spells. Methods: This case control study included 204 children (104 cases of breath-holding spells and 100 healthy children) younger than 3 years. Breath-holding spells were evaluated for age of onset, type (pallid/cyanotic), triggering factors, frequency and presence of family history. Twelve- lead surface electrocardiogram (ECG) was analyzed for QT interval (QT), corrected QT interval (QTc), QT dispersion (QTD) and QTc dispersion (QTcD) in milliseconds. Results: The mean (SD) QT, QTc, QTD and QTcD interval in milliseconds were 320 (0.05), 420 (0.07), 61.15 (16.20), 102.3 (17.24), respectively for breath-holding spells as compared to control group [300 (0.02), 370 (0.03), 38.6(14.28), 78.6 (14.28), respectively] (P<0.001). Similarly, pallid breathholding spells had prolonged mean (SD) QT, QTc, QTD and QTcD interval in milliseconds [380 (0.04), 520 (0.08), 78.88 (10.78), 123.33 (10.28), respectively] as compared to cyanotic spells [310 (0.04), 400 (0.04), 57.44 (14.64), 97.90 (15.03), respectively] (P<0.001). The mean QTc interval was 590 (0.03) and 400 (0.04) milliseconds in prolonged and non-prolonged QTc group, respectively (P<0.001). Conclusion: Abnormal QT, QTc, QTD and QTcD were observed among children with breath-holding spells. ECG should be strongly considered, especially in pallid, frequent spells occurring at younger age and having positive family history, to identify long QT syndrome.

Clinical features and follow-up of congenital long QT syndrome in children with syncope as the first presentation / 中国小儿急救医学

Objective:To investigate the pathogenic genes, clinical features and treatment as well as follow-up of children with congenital long QT syndrome (LQTS).Methods:The clinical data, genetic test results and follow-up data of 16 congenital LQTS children with syncope as the first manifestation admitted to the Department of Cardiology, Beijing Children′s Hospital Affiliated to Capital Medical University from August 2016 to March 2023 were collected and retrospectively analyzed.Results:Among the 16 LQTS patients, the age of first syncope onset was 1.3-13.3 (7.37±3.41) years, and the interval between first syncope onset and clinical diagnosis was 0-48 (14.8±16.2) months.A total of 13 (81.3%) patients had triggers of syncope, of which nine were exercise-induced and four were emotional induced.Genetic testing was performed in 13 patients with LQTS, of which 12 (92.3%) were found to have pathogenic or suspected pathogenic mutations from KCNQ1, KCNH2, and SCN5A gene.The corrected QT interval of 16 patients was (550.0±50.2) ms, all cases≥460 ms.Schwartz scored 6.0 (5.0, 6.0) points, all cases≥4 points.All patients were initially treated with metoprolol or propranolol, of which 14 patients were followed up to date, three patients had recurrent syncope, and five patients stopped taking the medicines by themselves.One patient with high-dose metoprolol (LQT2) was treated with mexiletine after recurrent episodes.One patient who was intolerant to high-dose propranolol underwent left cardiac sympathectomy and was followed up after surgery without syncope episodes.None of the patients underwent implantable cardioverter defibrillator implantation. Conclusion:Children with LQTS and syncope symptoms have high positive rate of genetic tests.The genetic results could assist typing of patients with LQTS and guide treatment.Routine electrocardiogram screening in children with syncope may diagnose LQTS earlier and reduce misdiagnosis and missed diagnosis.β-blockers are the cornerstone of treatment for patients with LQTS.Strengthening follow-up management and improving patients′ treatment compliance is conducive to further improving the treatment response rate of patients.

Determinação do risco potencial de interações medicamentosas prolongadoras do intervalo QT em idosos internados em unidade de terapia intensiva

Introdução: Pacientes hospitalizados em unidade de terapia intensiva, em especial idosos, são particularmente expostos a interações medicamentosas prolongadoras do intervalo QT. Objetivo: Determinar a incidência de interações medicamentosas prolongadoras do intervalo QT potenciais (IMQT) e seus preditores clínicos e terapêuticos em idosos hospitalizados em unidade de terapia intensiva. Metodologia: Coorte retrospectiva conduzida em unidade de terapia intensiva adulto. Foram incluídos prontuários de pacientes com idade igual ou superior a 60 anos com tempo de internação mínimo de 24 h e que utilizaram dois ou mais medicamentos. O Credi-bleMeds foi utilizado para classificação dos medicamentos com risco de prolongar o intervalo QT; em seguida, o Micromedex foi acessado para identificar e classificar as interações medicamentosas. Preditores clínicos e terapêuticos das interações foram examinados a partir de um modelo de regressão logística múltiplo. Resultados: A incidência de IMQT potenciais foi de 43,9 %. Os medicamentos mais frequentemente combinados nas IMQT potenciais foram ondansetrona (25 %), quetiapina (22,5 %), amiodarona (18,6 %) e haloperidol (17,5 %). As IMQT potenciais mais frequentes foram haloperidol + ondansetrona (25,4 %) seguidas pela dupla ondansetrona + quetiapina (13,1 %). Os preditores de IMQT potenciais foram uso de polifar-mácia (p=0,002), antipsicóticos (p<0,001), antidepressivos (p< 0,001) e antiarrítmicos (p=0,002). Conclusão: A gestão das IMQT requer abordagem pautada em fatores de risco individuais e também, obrigatoriamente, em condutas genéricas relativas a exames bioquímicos, instalação de monitores cardíacos, eletrocardiogramas periódicos e uso de sistemas de alerta para IMQT.

SUMMARY Introduction: Patients hospitalized in the intensive care unit, especially the elderly, are particularly exposed to drug interactions that prolong the QT interval. AIM: To determine the incidence of potential QT-prolonging drug interactions (IMQT) and their clinical and therapeutic predictors in elderly patients hospitalized in an intensive care unit. Methodology: Retrospective cohort conducted in an adult intensive care unit. Medical records of patients aged 60 years or older with a minimum hospital stay of 24 hours and who used two or more medications were included. CredibleMeds was used to classify drugs at risk of prolonging the QT interval; then, Micromedex was accessed to identify and classify drug interactions. Clinical and therapeutic predictors of interactions were examined using a multiple logistic regression model. Results: The incidence of potential IMQT was 43.9 %. The drugs most frequently combined in potential MTMI were ondansetron (25 %), quetiapine (22.5 %), amiodarone (18.6 %) and haloperidol (17.5 %). The most frequent potential MTMI were haloperidol + ondansetron (25.4 %) followed by the dual ondansetron + quetiapine (13.1 %). Potential IMQT predictors were use of polypharmacy (p=0.002), antipsychotics (p<0.001), antidepressants (p<0.001) and antiarrhythmics (p=0.002). Conclusion: The management of IMQT requires an approach based on individual risk factors and also, necessarily, on generic conducts related to biochemical tests, installation of cardiac monitors, periodic electrocardiograms and use of warning systems for IMQT.

Introducción: Los pacientes hospitalizados en la unidad de cuidados intensivos, especialmente los ancianos, están particularmente expuestos a interacciones medicamentosas que prolongan el intervalo QT. Objetivo: Determinar la incidencia de posibles interacciones medicamentosas prolongadoras del intervalo QT (IMQT) y sus predictores clínicos y terapéuticos en pacientes ancianos hospitalizados en una unidad de cuidados intensivos. Metodología: Cohorte retrospectiva realizada en una unidad de cuidados intensivos para adultos. Se incluyeron historias clínicas de pacientes de 60 años o más con una estancia hospitalaria mínima de 24 horas y que utilizaban dos o más medicamentos. Se utilizó CredibleMeds para clasificar los fármacos con riesgo de prolongar el intervalo QT; luego, se accedió a Micromedex para identificar y clasificar las interacciones medicamentosas. Los predictores clínicos y terapéuticos de interacciones se examinaron mediante un modelo de regresión logística múltiple. Resultados: La incidencia de IMQT potencial fue del 43,9 %. Los fármacos combinados con mayor frecuencia en posibles MTMI fueron ondansetrón (25 %), quetiapina (22,5 %), amiodarona (18,6 %) y haloperidol (17,5 %). Los MTMI potenciales más frecuentes fueron haloperidol + ondansetrón (25,4 %) seguido de ondansetrón dual + quetiapina (13,1 %). Los posibles predictores del IMQT fueron el uso de polifarmacia (p=0,002), antipsicóticos (p<0,001), antidepresivos (p<0,001) y antiarrítmicos (p=0,002). Conclusión: El manejo del IMQT requiere un abordaje basado en factores de riesgo individuales y también, obligatoriamente, en conductas genéricas relacionadas con pruebas bioquímicas, instalación de monitores cardíacos, electrocardiogramas periódicos y uso de sistemas de alerta para IMQT.

Prevalencia de medicamentos que prolongan el intervalo QT en salas de cardiología de un hospital de alta complejidad / Drug induced prolongation of Q-T interval in cardiology wards

Resumen: Antecedentes: La prevalencia del síndrome del QT largo (SQTL) producido por medicamentos es una de las reacciones adversas que en el último tiempo ha aumentado en prevalencia y mortalidad. No solamente ocurre con el uso de medicamentos para el tratamiento de cardiopatías, sino también en medicamentos con otra acción terapéutica. Objetivo: Evaluar la prevalencia del síndrome del SQTL inducido por medicamentos en salas de cardiología de un hospital de alta complejidad. Métodos: Estudio prospectivo, de tipo descriptivo y de corte transversal en 36 pacientes cardiópatas, que consistió en evaluar la frecuencia del uso de medicamentos que son capaces de producir un SQTL y la prevalencia de este efecto adverso. Los datos clínicos se recolectaron de la ficha clínica y de entrevistas con los pacientes. Se efectuó un seguimiento para detectar la aparición de prolongación del intervalo QT. Los resultados obtenidos fueron presentados por medio de estadística descriptiva (programa estadístico Statgraphics Centurion, versión XVI). No hubo estadística inferencial dada la ausencia de un grupo control. Resultados: 41,7%, de los 36 pacientes presentaron SQTL que en 86,7% de ellos fue asociado a un medicamento. Los medicamentos más frecuentemente asociados a este efecto adverso fueron Amiodarona (38,5%) y Ondansetrón (23,1%), y el factor de riesgo mayormente involucrado fue el sexo femenino (61,5%). Conclusión: Existió una alta prevalencia del uso de medicamentos que producen un SQTL, destacándose que existen medicamentos utilizados para otras patologías que también pueden producirlo.

Abstract: Background: The prevalence of the Long QT interval syndrome (LQTS) associated to drugs has increased en the last decades along with an increased mortality due to this condition. It occurs not only with drugs used to treat cardiac disease but also to other drugs. Aim: To evaluate the prevalence of drug induced LQTS in cardiology wards of a high complexity hospital. Method: This is a prospective, descriptive and cross sectional study in 36 patients with heart disease. The use of drugs known to affect the QT interval along with the frequency of LGTS were evaluated. Clincal data was obtained from clinical records and personal interviews. Patients were followed for the appearance of LQTS. Descriptive were used to present the results. No inferential statistics were used as no control group was involved (Statgraphics Centurion, version XVI). Results: 41.7% of the 36 patients developed LQTS and the association with drugs was present in 86.7% of them. The drugs most commonly identified were amiodarone (38.5%) and ondansetron (23.1%) of patients. Female geneder was the most common associated condition (61.5%). Conclusion: There was a frequent use of drugs known to produce LQTS, but other drugs may also be associated int this group of patients with heart disease admitted to intensive or intermediate care facilities.

Diagnostic Lacunae and Implications of an Automated Implantable Cardioverter Defibrillator Implantation in a Child with Type 3 Long QT (LQT3) Syndrome

A diagnosis of congenital long QT interval syndrome based on history and electrocardiogram was made in a child in the absence of readily available genetic testing. A genotype 3 (LQT3) was suspected after exclusion of other variants as the child was non?responsive to beta?blocker and sodium channel blocker medication. As the child continues to show episodic bradycardia, polymorphic ventricular ectopy, and T?wave alternans, a single?chamber automated implantable cardioverter?defibrillator implantation was done successfully. This report highlights how the diagnosis of LQT3 was arrived at as well as the anesthetic challenges in the management of patients with LQTS.

Mutation spectrum and clinical features of congenital long QT syndrome in 20 children: a single center study / 中华实用儿科临床杂志

Objective:To explore the pathogenic genes, clinical characteristics and treatment follow-up of children with congenital long QT syndrome (LQTS).Methods:Clinical data of 20 cases diagnosed with congenital LQTS and underwent gene testing from April 15, 2011 to April 15, 2021 in Department of Pediatric Cardiology, Shandong Provincial Hospital Affiliated to Shandong University were retrospectively collected and analyzed using independent sample t-test and Fisher′ s exact probability method. Results:LQTS-related gene mutations were detected in all the 20 cases, and pathogenic or suspected pathogenic mutations were identified in 18 cases (90.0%). Five LQTS mutation genes were discovered, including KCNQ1, KCNH2, SCN5A, CACNA1C and AKAP9.Eighteen cases (90.0%) had positive symptoms, and 13 cases (65.0%) had definite inducements.The inducement of symptoms in children with LQTS type 1(LQT1) was related to exercise, the causes of syncope in LQT1 and Jervell-Lange-Nielsen syndrome type 1 (JLNS1) with complex heterozygous mutations were exercise or emotional agitation; the causes of syncope in LQTS type 2 (LQT2) were unrelated to exercise; severe exercise in LQTS type 3 (LQT3) resulted in symptoms; and seizure in LQTS type 8 (LQT8) was non-induced.The corrected QT(QTc) interval of 20 cases was (553.1±66.6) ms, with a range of 460-707 ms, among which 17 cases showed QTc≥480 ms.The electrocardiogram(ECG) manifestations of children with various types of LQTS were different.There was no significant difference in QTc between different genders, or between children with syncope and those without syncope (all P>0.05). The follow-up time was (3.4±2.3) years, ranging from 0 to 8.3 years.Seventeen children received treatment[beta blockers and implantable cardiovertor-defibrillator(ICD)] and 3 cases did not.By the end of the follow-up, 1 child died, 19 cases survived, and 2 cases of the surviving children lost consciousness. Conclusions:There is a high consistency between genetic diagnosis and clinical diagnosis of congenital LQTS.The positive rate of gene detection is 90.0%.The clinical manifestations and ECG characteristics vary with genotypes.Beta blockers are protective.ICD therapy can prevent sudden cardiac death when oral medication does not respond.

Evaluation of cardiac safety of hydroxyrutaecarpine, hERG channel inhibitor / 药学学报

Drug-induced long QT syndrome (LQTS) has become an important clinical research topic, and the occurrence of acquired long QT syndrome (acLQTS) is mainly caused by drug inhibition of the human ether-α-go-go related gene (hERG) channel. The hERG gene encodes the α subunit of the fast-activating delayed rectifying potassium ion channel (Ikr), which plays an important role in the process of action potential phase 3 repolarization and is also the target of most antiarrhythmic drugs. The purpose of this study was to investigate the effect of hydroxyrutaecarpine (HRU) on the hERG channel and to evaluate its cardiotoxicity. The whole cell patch clamp technique was used to detect the effects of HRU on the current and kinetics of the hERG channel, and to confirm the binding site on the hERG channel. PCR was used to determine the effect of HRU on hERG mRNA expression. Western blotting was used to detect the effects of HRU on the expression of hERG protein and transcription factor Sp1. Immunofluorescence was used to confirm the effects of HRU on localization and expression of hERG protein and transcription factor Sp1. Studies have shown that transient HRU can inhibit hERG current and shorten the inactivation time constant. Its binding sites to the hERG channel are F656 and Y652. After incubation for 24 h, HRU can reduce the expression of hERG protein, inhibit the hERG current, reduce the level of hERG mRNA, and reduce the expression of transcription factor Sp1 in the nucleus and hERG protein in the cytoplasm. Immunofluorescence experiments also showed the same results suggesting that the inhibition of Sp1 expression by HRU is the cause of the decreased expression of hERG mRNA. In conclusion, the acute inhibition of HRU accelerates the channel inactivation process and reduces the inactivation time constant by binding to the F656 and Y652 sites in the hERG channel, thus reducing the hERG current. In addition, HRU also inhibits the expression of hERG protein, mainly by inhibiting the expression of transcription factor Sp1, the transcription function of hERG channel protein is down-regulated, so that the hERG protein is reduced.

Aborted Sudden Death Due to Severe Ventricular Arrhythmia in Timothy Syndrome

Abstract Timothy Syndrome is a rare autosomal dominant multisystem genetic condition. The CACNA1C gene, codifier of the CaV1.2 calcium channel, is affected, resulting in the loss of voltage-dependent calcium channel inactivation. Relevant clinical characteristics: (1) corrected QT interval greater than 480ms; (2) syndactyly. Death often occurs during childhood, and results from ventricular tachyarrhythmias. This study presents the case of a female newborn who suffered a cardiorespiratory arrest, secondary to ventricular arrhythmia. A prolonged QT interval, combined with 2:1 AV block, was also identified, requiring a definitive cardiac pacemaker implant that, during inpatient care, developed pulmonary sepsis, followed by death.

Prescription profile of antiarrhythmic drugs in a group of patients in Colombia / Perfil de prescripción de fármacos antiarrítmicos en un grupo de pacientes en Colombia

Abstract Objective: To determine the prescription patterns of antiarrhythmic drugs and variables associated with their use in a population of patients affiliated with the Colombian Health System. Methods: A cross-sectional study was performed on a population database with patients who received antiarrhythmics from March to May 2016. Sociodemographic, pharmacological and comedication variables were included. SPSS-24 was used for data analysis using X2 tests and multivariate analyses. Results: In total, 2772 patients were treated with antiarrhythmics in the evaluated period. The mean age was 70.1 ± 13.1 years, and 51.2% were women. In total, 79.4% used a β-blocker, 58.5% amiodarone and 2.9% a calcium channel blocker. Moreover, 1192 (43.0%) patients were prescribed a single antiarrhythmic, and 1580 (57.0%) received two or more. There were 2603 patients (93.9%) with comedication, including lipid-lowering drugs (62.6%), inhibitors of the renin angiotensin aldosterone system (62.6%) and antiplatelet drugs (42.0%). Age older than 65 years increased the probability of comedication (odds ratio [OR]: 2.48; 95% confidence interval [95% CI]: 1.59-3.85), and the risk was proportional to age. We identified 1364 patients treated with conditional risk medications for QT prolongation (49.2%), 68 with a possible risk (2.5%) and 171 (6.2%) with a known risk. Conclusion: Antiarrhythmic drugs recommended by clinical practice guidelines are mainly used; however, risk interactions interactions of QT prolongation were identified and should be taken into account by physicians to avoid adverse events or complications.

Resumen Objetivo: determinar los patrones de prescripción de fármacos antiarrítmicos y variables asociadas a su utilización en una población de pacientes afiliados al sistema de salud de Colombia. Métodos: estudio de corte transversal sobre una base de datos poblacional con pacientes que recibieron antiarrítmicos entre marzo y mayo de 2016. Se incluyeron variables sociodemográficas, farmacológicas y de comedicación. Para el análisis de datos se utilizó SPSS-24, realizando pruebas X2 y análisis multivariado. Resultados: se encontraron 2 772 pacientes en tratamiento con antiarrítmicos en el periodo evaluado, la edad promedio fue 70,1 ± 13,1 años, 51,2 % eran mujeres. El 79,4% utilizó algún β-bloqueador, 58,5% amiodarona y 2,9 % algún bloqueante de canales de calcio. Al 43 % se les prescribió un solo antiarrítmico y 57 % recibieron dos o más. El 93,9 % tenía con alguna comedicación, especialmente hipolipemiantes (62,6 %), inhibidores del sistema renina angiotensina aldosterona (62,6 %) y antiagregantes (42 %). Ser mayor de 65 años aumentó la probabilidad de comedicación (OR:2,48; IC95 %:1,59-3,85) y el riesgo fue proporcional al incremento de la edad. El 49,2 % (n=1364) estaban tratados con medicamentos de riesgo condicional de prolongación del QT, 2,5 % (n=68) con riesgo posible y 6,2% (n=171) de riesgo conocido. Conclusión: se están utilizando los mismos fármacos recomendados por las guías de práctica clínica; sin embargo, se encontraron interacciones de riesgo de prolongación del intervalo QT que deben ser tenidas en cuenta para evitar eventos o complicaciones en los pacientes.

Peculiaridade dos pacientes com arritmias hereditárias na pandemia pela COVID-19 / Peculiar aspects of patients with Inherited arrhythmias during the COVID-19 pandemic

Resumo Desde dezembro de 2019, observamos o rápido avanço da síndrome respiratória aguda grave causada pelo coronavírus 2019 (SARS-CoV-2). O impacto da evolução clínica de uma infecção respiratória é pouco conhecido em pacientes portadores de arritmias hereditárias, devido à baixa prevalência dessas doenças. Os pacientes que apresentam quadros infecciosos podem exacerbar arritmias primárias ocultas ou bem controladas, por diversos fatores, tais como febre, distúrbios eletrolíticos, interações medicamentosas, estresse adrenérgico e, eventualmente, o próprio dano miocárdico do paciente séptico. O objetivo desta revisão é destacar os principais desafios que podemos encontrar durante a pandemia pela Covid 19, especificamente nos pacientes com arritmias hereditárias, com destaque para a síndrome do QT longo congênito (SQTL), a síndrome de Brugada (SBr), a taquicardia ventricular polimórfica catecolaminérgica (TVPC) e a cardiomiopatia arritmogênica do ventrículo direito.

Abstract Since December 2019 we have observed the rapid advance of the severe acute respiratory syndrome caused by the new coronavirus (SARS-CoV-2). The impact of the clinical course of a respiratory infection is little known in patients with hereditary arrhythmias, due to the low prevalence of these diseases. Patients who present with infectious conditions may exacerbate hidden or well-controlled primary arrhythmias, due to several factors, such as fever, electrolyte disturbances, drug interactions, adrenergic stress and, eventually, the septic patient's own myocardial damage. The aim of this review is to highlight the main challenges we may encounter during the Covid 19 pandemic, specifically in patients with hereditary arrhythmias, with emphasis on the congenital long QT syndrome (LQTS), Brugada syndrome (SBr), ventricular tachycardia polymorphic catecholaminergic (CPVT) and arrhythmogenic right ventricular cardiomyopathy.

Prolongación del intervalo QT durante hipotermia terapéutica en un recién nacido con encefalopatía hipóxico isquémica: a propósito de un caso / Prolongation of the QT interval during therapeutic hypothermia in a newborn with hypoxic-ischemic encephalopathy: A case report / Prolongamento do intervalo QT durante hipotermia terapêutica em recém-nascido com encefalopatia hipóxico-isquêmica: relato de caso

Resumen: El síndrome de QT largo adquirido puede ser secundario a la hipotermia, tanto accidental como terapéutica. Es poco el conocimiento sobre el efecto de ésta en la actividad eléctrica cardíaca, sobre todo en recién nacidos, y sus potenciales complicaciones. Se presenta el caso clínico de un recién nacido con diagnóstico de encefalopatía hipóxico isquémica que presenta una prolongación del intervalo QT durante el tratamiento con hipotermia. Se discute la evolución del paciente, que es consistente con lo referido en la literatura sobre el tema: buena evolución, ausencia de arritmias graves o alteraciones hemodinámicas, y normalización del electrocardiograma luego de finalizado el tratamiento.

Summary: Acquired long QT syndrome may be secondary to hypothermia, both accidental and therapeutic. There is not enough knowledge about the effect of hypothermia in cardiac activity and its potential complications, especially in newborns. We present the clinical case of a newborn with a diagnosis of hypoxic ischemic encephalopathy who has a prolonged QT interval during treatment with hypothermia. The evolution of the patient is discussed, which is consistent with what is referred to in the literature on the subject: Good evolution, absence of serious arrhythmias or hemodynamic alterations, and normalization of the ECG after the end of treatment.

Resumo: A síndrome do QT longo adquirida pode ser secundária à hipotermia, tanto acidental quanto terapêutica. Pouco se sabe sobre seu efeito na atividade elétrica cardíaca, principalmente em recém-nascidos, e suas possíveis complicações. Apresentamos o relato de caso clínico de um recém-nascido com diagnóstico de encefalopatia hipóxica isquêmica que apresenta prolongamento do intervalo QT durante o tratamento com hipotermia. Discutimos a evolução do paciente, a que é consistente com a literatura sobre o assunto: boa evolução, ausência de arritmias graves ou alterações hemodinâmicas e normalização do ECG após o término do tratamento.

Síndrome de QT largo en la embarazada con el uso de la oxitocina

RESUMEN Introducción: Los síndromes de QT largo adquiridos pueden ser provocados por el uso de fármacos, dentro de los cuales se encuentra la oxitocina. Objetivo: Identificar los cambios electrocardiográficos con el uso de la oxitocina intravenosa en la embarazada. Método: Se realizó un estudio descriptivo-prospectivo con 57 embarazadas a las que se les realizó cesárea electiva y se le administró oxitocina, inmediatamente después de la extracción fetal, en el Hospital Universitario Gineco-Obstétrico Mariana Grajales de Villa Clara, Cuba, durante el período de septiembre de 2019 a enero de 2020. Resultados: El 63,2% de las pacientes tuvo un QT corregido 470 ms; en estas últimas, un 5,3% lo tuvo entre 481-500 ms, e igual porcentaje > 500 ms. Ninguna paciente presentó síntomas sugestivos o demostración electrocardiográfica de taquicardia ventricular u otras arritmias complejas. Conclusiones: La oxitocina, administrada en el período de alumbramiento, produjo prolongación del intervalo QT por encima de los valores normales en algunas pacientes, sin que se produjeran síntomas cardiovasculares, dispersión del QT o arritmias complejas.

ABSTRACT Introducción: Acquired long QT syndromes may be due to the use of drugs, within which oxytocin is included. Objetivo: To identify electrocardiographic disturbances related to intravenous oxytocin administration in pregnant women. Método: A descriptive-prospective study was conducted with 57 pregnant women who underwent elective caesarean section and were given oxytocin, immediately after fetal extraction, at the Hospital Universitario Gineco-Obstétrico Mariana Grajales in Villa Clara, Cuba, between September 2019 and January 2020. Resultados: The 63.2% of the patients had a corrected QT interval 470 ms; in the latter, 5.3% had it between 481-500 ms, and equal percentage > 500 ms. No patient presented suggestive symptoms or electrocardiographic demonstration of ventricular tachycardia or other complex arrhythmias Conclusiones: Oxytocin, given during the placental removal period, resulted in the prolongation of the QT interval above normal values in some patients, without the appearance of cardiovascular symptoms, QT interval dispersion or complex arrhythmias.

Descripción de dos familias con síndrome de QT largo / Description of 2 families with long QT syndrome

Resumen El síndrome de QT largo representa un grupo de desórdenes electrofisiológicos cardiacos, caracterizados por la prolongación del intervalo QT, que se asocian a muerte súbita, taquicardias ventriculares y síncope. Se presenta el caso de dos familias con la descripción clínica de los afectados, el estudio genético y el respectivo manejo, y se hace una breve actualización de la literatura sobre el síndrome de QT largo.

Abstract Long QT syndrome represents a group of electrophysiologic disorders characterized by a prolongation in the QT interval that are associated with sudden death, ventricular tachycardia and syncope. We present 2 families describing the clinical presentation, the genetic study and their respective treatment also there is a brief review about long QT syndrome.

Risk factors for cardiac events in children with long QT syndrome: a single-center study / 中华实用儿科临床杂志

Objective:To identify the risk factors for cardiac events like recurrent syncope and fatal events in children with long QT syndrome (LQTS).Methods:A retrospective review involving 69 children with LQTS with the age of (7.6±4.2) years (43 male patients, 26 female patients) admitted in the Heart Center, Division of Pediatric Cardiology, First Hospital of Tsinghua University from August 2013 to March 2019 was conducted.Medical history, surface electrocardiogram, Doppler echocardiography and screening results of pathogenic genes of each patient were analyzed.Patients were divided into cardiac event group (32 cases) and non-cardiac event group (37 cases) according to the presence or absence of cardiac events like syncope or sudden death.Differences between 2 groups were compared using the independent sample Student′s t test and Chi- square test. Results:There were 32 cases among 69 children (46.4%) had recurrent syncope, involving 2 deaths, 14 cases among 69 children (20.3%) had a positive family history and 8 cases among 69 children (11.6%) had family history of sudden death.There were 52 cases among 69 children (75.4%) had arrhythmias.Among them, 32 patients (46.4%) with ventricular arrhythmia, including 11 cases (15.9%) with torsades de pointes (TdP). Ten LQTS-associated pathogenic or pathogenic pathologic mutations were found in 53 cases among 69 children (76.8%). Children with cardiac events had a younger mean age of onset [(4.7±4.1) years vs.(7.4±3.7) years, t=-2.856, P=0.006], a longer mean corrected QT (QTc) [(529±66) ms vs.(478±52) ms, t=3.537, P=0.001] and a higher incidence of TdP (34.4% vs.0%, P<0.001) compared with those who did not have cardiac events.Pathogenic mutations of KCNQ1 and KCNH2 were more frequent in children with cardiac events (62.5% vs.18.9%, χ2=14.178, P=0.001). Conclusions:Children with LQTS are prone to cardiac events.Children with a younger onset age, a longer QTc duration, malignant ventricular tachycardia and mutations of the KCNQ1 and KCNH2 genes are more frequently complicated by cardiac events.

Smartphone electrocardiogram for QT interval monitoring in Coronavirus Disease 2019 (COVID-19) patients treated with Hydroxychloroquine

@#Introduction: The global pandemic of Corona Virus Disease 2019 (COVID-19) has led to the re-purposing of medications, such as hydroxychloroquine and lopinavir-ritonavir in the treatment of the earlier phase of COVID-19 before the recognized benefit of steroids and antiviral. We aim to explore the corrected QT (QTc) interval and ‘torsadogenic’ potential of hydroxychloroquine and lopinavir-ritonavir utilising a combination of smartphone electrocardiogram and 12-lead electrocardiogram monitoring. Materials and Methods: Between 16-April-2020 to 30-April2020, patients with suspected or confirmed for COVID-19 indicated for in-patient treatment with hydroxychloroquine with or without lopinavir-ritonavir to the Sarawak General Hospital were monitored with KardiaMobile smartphone electrocardiogram (AliveCor®, Mountain View, CA) or standard 12-lead electrocardiogram. The baseline and serial QTc intervals were monitored till the last dose of medications or until the normalization of the QTc interval. Results: Thirty patients were treated with hydroxychloroquine, and 20 (66.7%) patients received a combination of hydroxychloroquine and lopinavir-ritonavir therapy. The maximum QTc interval was significantly prolonged compared to baseline (434.6±28.2msec vs. 458.6±47.1msec, p=0.001). The maximum QTc interval (456.1±45.7msec vs. 464.6±45.2msec, p=0.635) and the delta QTc (32.6±38.5msec vs. 26.3±35.8msec, p=0.658) were not significantly different between patients on hydroxychloroquine or a combination of hydroxychloroquine and lopinavir-ritonavir. Five (16.7%) patients had QTc of 500msec or more. Four (13.3%) patients required discontinuation of hydroxychloroquine and 3 (10.0%) patients required discontinuation of lopinavirritonavir due to QTc prolongation. However, no torsade de pointes was observed. Conclusions: QTc monitoring using smartphone electrocardiogram was feasible in COVID-19 patients treated with hydroxychloroquine with or without lopinavir-ritonavir. The usage of hydroxychloroquine and lopinavir-ritonavir resulted in QTc prolongation, but no torsade de pointes or arrhythmogenic death was observed.