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.

Severe hypokalemia secondary to abuse of ß-adrenergic agonists in a pediatric patient: Case report / Hipocalemia grave secundária a abuso de agonistas ß-adrenérgicos em paciente pediátrico: relato de caso

ABSTRACT This study reports a case of a 13-year-old male with a 3-year history of severe and intermittent hypokalemia episodes of unknown origin, requiring admission to the intensive care unit (ICU) for long QT syndrome (LQTS), finally diagnosed of redistributive hypokalemia secondary to the abuse of β-adrenergic agonists in the context of a probable factitious disorder.

RESUMO O presente estudo relata o caso de um jovem de 13 anos de idade com histórico, há três anos, de episódios de hipocalemia grave intermitente de origem desconhecida, internado em unidade de terapia intensiva (UTI) por síndrome do QT longo (SQTL). O paciente foi diagnosticado com hipocalemia por redistribuição secundária ao abuso de agonistas β-adrenérgicos, em contexto de provável transtorno factício.

Effect of artemisinin-piperaquine treatment on the electrocardiogram of malaria patients

Abstract INTRODUCTION: Concern regarding the cardiotoxicity of antimalarials has been renewed because of their potential to cause QT/QTc interval prolongation related to torsade de pointes (TdP). Artemisinin-piperaquine (AP) is considered an effective artemisinin-based combination therapy (ACT) for malaria. METHODS: This study involved a retrospective analysis of clinical data of 93 hospitalized malaria patients who had received AP orally. Electrocardiograms (ECGs) were obtained at specific time points in the original study. RESULTS: Some cases of QT prolongation were observed. However, no TdP was found. CONCLUSIONS: AP may cause QT interval prolongation in some malaria patients but may not lead to TdP.

Medicamentos que podem induzir prolongamento do intervalo QT utilizados por idosos em domicílio / Medications that can induced QT prolongation used by elderly at home

O intervalo QT (iQT), parâmetro eletrocardiográfico, é um biomarcador não invasivo da repolarização ventricular. O aumento do iQT é uma alteração que pode ser de considerável importância clínica, pois predispõe a torsade de pointes e morte cardíaca súbita. O objetivo do presente trabalho é identificar os medicamentos utilizados em domicílio por idosos, que podem induzir o prolongamento do iQT. Trata-se de um estudo quantitativo descritivo exploratório e retrospectivo, realizado em um hospital público de ensino. Foram incluídos 190 idosos com informação sobre uso domiciliar de medicamentos registrada em prontuário. A mediana da idade foi de 69,5 anos, sendo 99 (52,1%) mulheres. O número de medicamentos utilizados por paciente em domicílio apresentou mediana de 4,0. Foram identificados 159 fármacos, sendo que 23 (14,5%) apresentavam capacidade de induzir prolongamento do iQT. Entre os idosos, 39 (20,5%) usavam estes fármacos, sendo os mais prevalentes a amiodarona, amitriptilina, nortriptilina, citalopram e fluoxetina. A hipertensão arterial foi o fator de risco mais frequente dentre aqueles que predispõem a prolongamento do iQT. As utilizações de medicamentos que induzem prolongamento do iQT e a presença de fatores de risco predisponentes mostram que os idosos estão expostos ao risco de desenvolvimento de torsade de pointes. A identificação dos fármacos que induzem prolongamento do iQT, das interações medicamentosas e das condições clínicas que predispõem a esse prolongamento são importantes para garantia da segurança da farmacoterapia de idosos e para evitar eventos adversos graves.(AU)

The QT interval (QTi), an electrocardiographic parameter, is a noninvasive biomarker of ventricular repolarization. Increased QTi is a change that may have clinical importance because predisposes to torsade de pointes and sudden cardiac death. The objective of this study was to identify drugs used by elderly at home which may induce QTi prolongation. This is a quantitative, retrospective, descriptive, exploratory study conducted in a teaching hospital. A total of 190 elderly with information on the use of medications at home available in medical records were included in the study. The median age was 69.5 years, and 99 (52.1 %) were female. The median number of medications used per patient at home was 4.0. A variety of 159 drugs were identified including 23(14.5%) that may induce QTi prolongation. Among the 39 elderly (20.5%) using drugs that may induce QTi prolongation, the most frequent were: amiodarone, amitriptyline, nortriptyline, citalopram and fluoxetine. Hypertension was the most frequent risk factor for QTi prolongation. The use of these drugs and the presence of risk factors place the elderly at increased risk for developing torsade de pointes. The identification of drugs that may induce QTi prolongation, drug-drug interactions and clinical conditions that may lead to this adverse effect reinforces the need for actions to ensure the drug safety in the elderly population and to avoid serious adverse events.(AU)

QT interval prolongation associated with azithromycin/methadone combination / Prolongación del intervalo QT asociada con combinación de azitromicina/metadona

This report documents the occurrence of QT prolongation in a 57-year old man, on methadone replacement therapy, treated with azithromycin for community acquired pneumonia. This case highlights a hitherto unknown drug interaction. In light of ever-increasing use of azithromycin, it is imperative that azithromycin be used with caution in patients who are already on drugs that are known to cause QT prolongation or that cause torsades de pointes.

Este reporte documenta la ocurrencia de la prolongación del intervalo QT en un hombre de 57 años, en la terapia de reemplazo con metadona, tratado con azitromicina por pulmonía adquirida en la comunidad. Este caso destaca una interacción de medicamentos desconocida hasta ahora. En vista del uso cada vez mayor de la azitromicina, resulta absolutamente necesario usarla con precaución en pacientes que ya están bajo tratamiento con medicamentos de los cuales se sabe que causan prolongación del intervalo QT o que causan torsades de pointes.

Serum levels of magnesium in sudden cardiac deaths among people with schizophrenia: hit or miss? / Níveis séricos de magnésio em morte súbita entre pessoas com esquizofrenia: erro ou acerto?

Schizophrenia is a devastating mental disorder, affecting cognitive, emotional, and behavioral conditions, ability to work, social functioning, family stability and self-esteem of the patient. People with schizophrenia show a two to three-fold increased risk to die prematurely than those without schizophrenia. Understanding the mechanisms behind sudden cardiac death in individuals with schizophrenia is a key to prevention. Although different mechanisms may be related, there are clear indications that cardiac abnormalities play a potential role. Some antipsychotics may be associated with cardiovascular adverse events, e.g., QT interval prolongation, metabolic dysfunction, blood pressure and heart rate alterations. Magnesium (Mg) abnormalities may lead to various morphological and functional dysfunctions of the heart and low levels of serum Mg are considered to be at high risk for sudden cardiac death. As low serum Mg is associated with detrimental effects on the heart and that antipsychotic-treated schizophrenia patients frequently affect the heart rate, possibly, these factors together must change the normal functioning of the heart and consequently being able to culminate in a catastrophic event.

A esquizofrenia é uma doença mental que afeta as condições cognitivas, emocionais e comportamentais, a capacidade de trabalho, a estabilidade familiar e social e a auto-estima do paciente. Pessoas com esquizofrenia apresentam um risco de duas a três vezes maior de morrer prematuramente em relação às pessoas sem esquizofrenia. A compreensão dos mecanismos envolvidos na morte súbita em indivíduos com esquizofrenia é de suma importância para sua prevenção. Apesar de diferentes mecanismos associados à doença, evidências mostram que as anormalidades cardíacas desempenham papel importante neste contexto. Alguns antipsicóticos podem estar associados com eventos cardiovasculares adversos, como o prolongamento do intervalo QT, disfunção metabólica e alterações na pressão arterial e no ritmo cardíaco. Anormalidades do magnésio (Mg) podem levar a várias alterações morfológicas e funcionais do coração assim como a um alto risco para a morte súbita. Como baixos níveis séricos de Mg estão associados a efeitos nocivos ao coração e indivíduos com esquizofrenia tratados com antipsicóticos frequentemente apresentam alteração do ritmo cardíaco, possivelmente, estes fatores em conjunto podem alterar o funcionamento normal do coração e, consequentemente, culminar em um evento catastrófico.

Life-threatening overdose with lamotrigine, citalopram, and chlorpheniramine.

Lamotrigine is a commonly used agent for seizure control in epilepsy. There are limited data on the adverse effects of lamotrigine in overdose. We report a number of serious side-effects associated with a large overdose of lamotrigine. A 23-year-old female presented to the emergency department after taking an intentional overdose of 9.2 g of lamotrigine, 56 mg of chlorpheniramine, and 220 mg of citalopram. On admission, she had a reduced level of consciousness and electrocardiographic abnormalities; a widened QRS and a prolonged corrected QT (QTc) interval. Prompt treatment with early intubation, along with the use of magnesium for cardioprotection and administration of sodium bicarbonate may have aided in a quick recovery with a short intensive care stay and good outcome.

Nuevas perspectivas en el síndrome de QT largo / New perspectives in long QT syndrome

Long QT Syndrome (LQTS) is a cardiac channelopathy characterized by prolonged ventricular repolarization and increased risk to sudden death secondary to ventricular dysrrhythmias. Was the first cardiac channelopathy described and is probably the best understood. After a decade of the sentinel identification of ion channel mutation in LQTS, genotype-phenotype correlations have been developed along with important improvement in risk stratification and genetic guided-treatment. Genetic screening has shown that LQTS is more frequent than expected and interestingly, ethnic specific polymorphism conferring increased susceptibility to drug induced QT prolongation and torsades de pointes have been identified. A better understanding of ventricular arrhythmias as an adverse effect of ion channel binding drugs, allow the development of more safety formulas and better control of this public health problem. Progress in understanding the molecular basis of LQTS has been remarkable; eight different genes have been identified, however still 25% of patients remain genotype-negative. This article is an overview of the main LQTS knowledge developed during the last years.

El síndrome de QT largo (SQTL) es una canalopatía que genera grave alteración en la repolarización ventricular predispone a arritmias malignas y muerte súbita. Fue la primera canalopatía arritmogénica descrita y quizá la mejor entendida hasta ahora. Transcurrida ya más de una década de la identificación de la primera mutación asociada al SQTL, se ha hecho evidente que este trastorno es mucho más frecuente de lo que inicialmente se pensaba; los avances en el conocimiento de la fisiopatología molecular de esta enfermedad han permitido hacer una correlación genotipo-fenotipo, optimizando el tratamiento y permitiendo estratificar el riesgo en forma precisa. Se ha logrado entender con mayor detalle los efectos adversos de distintas drogas que interactúan con los canales iónicos, permitiendo así generar fármacos más seguros y, en su defecto, monitorizar de cerca aquellos que a pesar de tener este efecto adverso, es necesaria su administración. Los avances son importantes pero no todo está dicho, 25% de los casos no tienen mutaciones en los genes descritos hasta la fecha, por lo que el SQTL continúa siendo motivo de investigación. El presente artículo constituye un resumen de los principales conceptos desarrollados en los últimos diez años que han sido cruciales en el manejo de esta enfermedad.

Intervalo QT prolongado inducido por fármacos desde el punto de vista de un farmacólogo / Drug induced QT interval prolongation: a pharmacologist's point of view

El síndrome QT largo adquirido es provocado principalmente por el uso de fármacos que prolongan la repolarización ventricular. Si bien es conocido que la mayoría de los antiarrítmicos presentan esta propiedad, también es compartida por alrededor de 100 drogas no antiarrítmicas. Pese a que el riesgo de proarritmia con la mayoría de estos fármacos es bajo, la incidencia de esta reacción adversa es importante debido a su amplio uso. Por otro lado, existen numerosos factores predisponentes que incrementan el riesgo de torsade de pointes, como la predisposición genética, el sexo femenino, la hipopotasemia y la disfunción cardíaca. Además, la mayoría de los casos de torsade de pointes inducido por fármacos se han detectado en pacientes tratados con más de un fármaco que presenta esta propiedad o bajo tratamiento con un inhibidor enzimático. De acuerdo con esto, la mayoría de los casos de síndrome QT largo adquirido se podrían evitar mediante una selección correcta del paciente, así como con un control adecuado de la terapia farmacológica. Por lo tanto, es de interés que los distintos profesionales de la salud estén actualizados en esta problemática y puedan aplicar medidas para evitar o reducir la incidencia de esta proarritmia.

Un caso de prolongación del intervalo QT asociado a consumo de metadona / QT interval prolongation associated with methadone consumption: report of a case

La farmacodependencia es una epidemia de nuestro tiempo, con graves consecuencias sanitarias y económicas, tanto para la sociedad como para el individuo. A continuación presentamos el caso clínico de un hombre de 37 años con antecedentes de abuso de drogas (cocaína, antidepresivos, benzodiacepinas y heroína), en tratamiento con metadona, y que es hallado en su hogar en coma. Tras presentar síndrome de deprivación se reinició metadona, a partir del tercer día de evolución presenta bradicardia sinusal progresiva, con prolongación del intervalo QT hasta 0,64 segundos y un episodio de fibrilación ventricular (FV), que responde a desfibrilación con 200 J. Se sospecha rol etiológico de la metadona y se inicia su descenso gradual. Se observa en los días sucesivos la progresiva y definitiva normalización del ritmo y duración del intervalo QT (Figura 1, 2, 3). Consideramos que la medición rutinaria del intervalo QT corregido parece justificada en presencia de factores de riesgo y cuando se está prescribiendo fármacos con conocido efecto sobre él.

Intervalo QTU prolongado durante el uso de cisapride / Prolonged QTU interval during cisapride use

El cisapride es el fármaco de elección en casos de reflujo gastroesofágico. Dentro de sus efectos colaterales se detalla la prolongación del intervalo QTU. En este artículo describimos un caso de prolongación del QTU probablemente asociado a esta medicación. El uso del cisapride debe ser vigilado, particularmente en grupos de alto riesgo, por lo que se recomienda realizar electrocardiogramas seriados. También deben recordarse los otros fármacos que prolongan el QT que no deben asociarse al cisapride y tampoco combinarse entre sí

La cisaprida no altera el intervalo Q-T prolongado en pacientes con cirrosis hepática / Cisapride does not modify prolonged Q-T interval in patients with liver cirrhosis

Background: Abnormal small bowel motility, observed in liver cirrhosis, can be reversed with cisapride. Since both cisapride and liver disease are associated with prolonged QT interval, the possibility of adverse cardiovascular effects might be expected with cisapride treatment in these patients. Aim: To evaluate QT interval and other electrocardiographic changes during long term treatment with cisapride in cirrhotic patients. Patients and methods: Forty seven cirrhotic patients were studied. Electrocardiogram was recorded and the QT interval corrected according to Bazzett's formula was determined (normal value <0.44 s). Seventeen patients were treated with cisapride, 10 mg tid for seven months and electrocardiographic controls were performed at the end of the treatment. Results: The mean corrected QT interval was 0.46 ñ 0.03 s (range 0.4-0.53). 34 patients (64 percent) had QTc prolongation (0.47 ñ 0,02 s). Statistically significant higher values of QTc were observed in patients at Child Pugh stage B and C compared to stage A. No statistically significant difference according to the etiology of liver disease, were observed. No changes in mean QTc duration were observed during cisapride treatment. Conclusions: In spite that a prolonged QTc was a frequent finding in our serie of selected patients, no cardiovascular adverse effects were observed with long term cisapride treatment