Supraventricular tachyarrhythmia and sinus node dysfunction as a first manifestation of short QT syndrome in a pediatric patient. Case Report.

Short QT syndrome (SQTS) represents a diagnosis challenge where the symptoms may vary from palpitations in an otherwise asymptomatic patient to sudden death. Is a recently discovered rare channelopathy, identified by Gussak in 2000, characterized by short QT intervals on the electrocardiogram and a tendency to develop atrial and ventricular arrhythmias in the absence of structural heart disease, hyperkalemia, hypercalcemia, hyperthermia, acidosis and endocrine disorders. We present the case of a 16-year-old patient with short QT-type channelopathy, who presented with sinus arrest and junctional rhythm, who later developed atrial tachycardia and atrial flutter.

Use of Infliximab in the Treatment of Macrophage Activation Syndrome Complicating Kawasaki Disease.

Kawasaki disease (KD) is an acute systemic vasculitis of unknown etiology. KD can be complicated with macrophage activation syndrome. The optimal treatment for this KD complication has not been established, and a variety of treatments have been used. Infliximab, a chimeric monoclonal antibody that binds tumor necrosis factor, has proved to be efficacious in IV gammaglobulin resistant KD. We present 2 cases of KD complicated with macrophage activation syndrome, including 1 patient with DiGeorge syndrome successfully treated with a combined treatment of IV gammaglobulin, corticosteroids, cyclosporine, and infliximab.

Long QT syndrome, utility of bicameral pacemaker.

The use of implantable cardioverter defibrillator (ICD) in pediatric age represents a challenge, because of anatomic limitations, increased risk of lead fracture, T wave oversensing and inappropriate therapies.

Pediatrics patients head-up tilt test with pharmacological challenge, it is safe?

Syncope in pediatrics represents an important cause of visits to the emergency units. For this reason, excluding a cardiac or malignant origin is essential at the time of the initial approach in order to determine what is the next step in management, or if they need to be referred to a pediatric cardiologist and/or electrophysiologist. Vasovagal syncope is the most frequent cause of syncope in pediatrics, in which a detailed clinical history is enough to make the diagnosis. If no diagnosis is concluded by the history, or if it is necessary to define the hemodynamic response of the patients, the head-up tilt test is indicated; this will trigger syncope due to an orthostatic stress caused by the angulated table (passive phase). If a negative response remains, it can be followed by a pharmacologic challenge in order to trigger the hemodynamic response, which is still controversial in pediatrics. The pharmacologic challenge increases the sensitivity with a slight reduction in test specificity. Although there is not a specific drug for the challenge in pediatric patients yet, the most commonly drugs used are nitrates and isoproterenol, the latter related to a great number of adverse effects. Sublingual administration of nitrates in the challenge has been proven to be ideal, effective and safe in this specific age group. The aim of this article is to make a literature search in order to demonstrate the effectiveness and safety of the pharmacologic challenge during the head-up tilt test in pediatrics, emphasizing a study conducted at the National Institute of Cardiology with isosorbide dinitrate.

El síncope en edades pediátricas representa una causa importante en las visitas a unidades de urgencias, por lo que excluir un origen cardíaco o maligno es fundamental al momento del abordaje inicial para determinar la conducta a seguir o la necesidad de derivar al cardiólogo pediatra o electrofisiólogo. El síncope vasovagal (SVV) es la causa más frecuente de síncope en pediatría, para cuyo diagnóstico basta una historia clínica detallada. Cuando ésta no es suficiente para determinar el diagnóstico de síncope reflejo o es necesario definir el tipo de respuesta que lo origina, está indicada una prueba de mesa inclinada que produce un estrés ortostático por la angulación y ello desencadena un síncope (fase pasiva). En pruebas no concluyentes está indicado un reto farmacológico para precipitar la respuesta hemodinámica, pero aún es un tema de controversia en edades pediátricas. El reto farmacológico incrementa la sensibilidad de la prueba, con una ligera reducción de la especificidad. Si bien no existe todavía un medicamento específico para la población pediátrica, los más empleados son los nitratos y el isoproterenol, este último relacionado con un mayor número de efectos adversos. La administración sublingual de los nitratos utilizados ha demostrado ser ideal, efectiva y segura en los pacientes pediátricos. El objetivo del artículo es realizar una revisión de las publicaciones médicas que demuestran la efectividad y seguridad del reto farmacológico durante la prueba de mesa inclinada en pacientes pediátricos, con énfasis en un estudio conducido en el Instituto Nacional de Cardiología con dinitrato de isosorbida (DNIS).

[Diagnosis of tachycardias in pediatric patients]. / Diagnóstico de las taquiarritmias en el paciente pediátrico.

Arrythmias in the pediatric patient usually are considered rare; nonetheless, their number is increasing. The paroxistic supraventricular tachycardia is the most frequent symptomatic arrhythmia. The diagnosis is based on electrocardiographic register. There are few diagnostic tools including the Hotter monitoring and loop recorders. Once the tachychardia is detected, a deductive electrocardiographic diagnosis and specific treatment are established.

[Incidence and clinical features of arrhythmias after surgical treatment of congenital heart disease]. / Incidencia y comportamiento clínico de las arritmias en pacientes con corrección quirúrgica de cardiopatías congénitas.

Congenital heart disease is associated with arrhythmias. Not only the congenital anatomic component but also the greater arrhythmogenic substrate related to surgical procedures is associated with the increased incidence of arrhythmias in these patients. In pediatric cardiology the study of these phenomena is becoming important and one factor associated with it is the longer follow up, which varies depending on the type of heart disease and arrhythmia. With the same impact, there are daily breakthroughs in diagnostic and treatment through pharmacological and interventional means. The incidence of arrhythmias in post-surgical patients with congenital heart disease is in constant increment, and this is related to the constant increment in the procedures, variety and frequency, as well as the long-term survival.

[Incidence and clinical behavior of arrhythmias associated with congenital heart disease and surgical treatment]. / Incidencia y comportamiento clínico de las arritmias asociadas con cardiopatía congénita y corrección quirúrgica.

Congenital heart disease is associated with arrhythmias. Not only the congenital anatomic settings but also the arrhythmogenic substrate related to surgical procedures is associated with the increased incidence of arrhythmias in these patients. In the National Institute of Cardiology, we reviewed retrospectively 128 clinical records of patients subjeted to surgical treatment of congenital heart disease (81 Fontan surgery, 19 with anomalous pulmonary drainage, 19 Fallot tetralogy). The incidence of supraventricular tachycardia was 8.6%, and the bradyarrhythmias were 15% with AV block in different degrees. Permanent pacing was required in 7.8% of the patients. The incidence of arrhythmias in post-surgical patients with congenital heart disease is increasing constantly.

[Atrial fibrillation: rhythm vs. rate control]. / Fibrilación atrial: control del ritmo vs. control de la frecuencia.

The atrial fibrillation treatment has been controversial since almost a century. Several studies have been done and there is not a clear therapeutic strategy despite the new technological advances. The disyuntive persist between sinus rhythm control vs. ventricular rate control. The main studies like AFFIRM, RACE, PIAF, PAF2 and STAF have not shown a definitive strategy treatment. Recently, several subgroups have been stablished and variables like life quality and functional state have been included. New therapeutic strategies have resulted. Heart rate control is recommendable for asymptomatic 65 years old patients and older, whereas rhythm control is better for patients with severe symptoms.

[Surgical radiofrequency catheter ablation of accessory pathways in Ebstein's anomaly]. / Ablación transquirúrgica de vía accesoria atrioventricular en anomalía de Ebstein.

Thirteen patients with Ebstein anomaly and atrioventricular reentrant tachycardia and at least one accessory pathway were included in this study. One accessory pathway in 7 (53.8%) patients and multiple accessory pathways in 6 (46.1%) were found. Mahaim accessory pathway was observed in 5 (38.4%) patients. A total of 22 accessory pathways was found, 2 (9%) were concealed. In all (100%), the accessory pathways were located in the tricuspid ring. The most frequent regions were right lateral free wall with 11 (50%) and 5 right posteroseptal (22.7%). Ten patients underwent surgical radiofrequency catheter ablation and three subjected to surgical section. We obtained success in 100%. No complications were observed during the procedures. In conclusion, surgical ablation therapy in patients with accessory pathways and Ebstein's anomaly is safe and effective.

[Refractory, incomplete and atypical Kawasaki disease. Case report and review of the literature]. / Enfermedad de Kawasaki refractaria, incompleta y atípica. Informe de un caso y revisión de la bibliografía.

We report the case of a 2 year 7 month old boy with the diagnosis of incomplete and atypical Kawasaki disease, whom showed only two of the classical criteria: fever and conjunctival injection without exudate, presenting clinical manifestations that are reported less often, such as gallbladder hydrops, aseptic meningitis, arthralgia, sterile pyuria, coronary aneurysms and myocardial ischemia. This patient had recurrent and refractory Kawasaki disease not responding to treatment with intravenous immunoglobulin and thus requiring steroids and immunosuppressive management.

Diagnóstico de las taquiarritmias en el paciente pediátrico / Diagnosis of tachycardias in pediatric patients

Arrythmias in the pediatric patient usually are considered rare; nonetheless, their number is increasing. The paroxistic supraventricular tachycardia is the most frequent symptomatic arrhythmia. The diagnosis is based on electrocardiographic register. There are few diagnostic tools including the Hotter monitoring and loop recorders. Once the tachychardia is detected, a deductive electrocardiographic diagnosis and specific treatment are established.

Radiofrequency ablation of atrioventricular accessory pathways associated with discordant atrioventricular connections.

Discordant atrioventricular connections associated with Wolff-Parkinson-White syndrome increase the challenge of radiofrequency ablation. We report the results and techniques of radiofrequency ablation in three patients with discordant atrioventricular connections, including one patient having double outlet right ventricle with atrioventricular reentry tachycardias. There were two males and one female, aged 14 and 22 years old. We found four accessory pathways during our electrophysiological studies, with two of them manifest on the electrocardiogram, corresponding to left paraseptal and right midseptal regions. The electrophysiological study confirmed this localization, and showed two concealed accessory pathways in the right and left paraseptal regions. Radiofrequency ablation was successful in all cases without recurrence at a mean follow-up of 18.6 months. No complications were observed during the procedures. We conclude that radiofrequency ablation is feasible and effective in the ablation of accessory pathways in patients with discordant atrioventricular connections.