Current status of pediatric electrophysiology in Latin America: a LAHRS survey.

PURPOSE: Over the last years, pediatric electrophysiology (EP) has evolved as a consolidated subspecialty of pediatric cardiology. In the USA, Canada, and Europe, there is a clear picture of the status of pediatric EP, but the situation in Latin America is largely unknown. METHODS: A descriptive cross-sectional observational study was performed. A survey was conducted by the Latin American Heart Rhythm Society in Spanish and Portuguese to assess the status of development of pediatric EP across Latin American countries. RESULTS: There are physicians practicing pediatric EP in 11 Latin American countries. The scope of the practices includes clinical and non-invasive EP as well as performing invasive EP procedures. All the current pediatric EP interventions are performed in most of Latin American countries. CONCLUSIONS: Pediatric electrophysiology is present as a subspecialty in half of the countries in Latin America, and all the current electrophysiology procedures and therapeutic technologies are available in most Latin American countries.

Uso de la ivrabadina para el tratamiento de la taquicardia ectópica de la unión congénita / Use of ivabradine for the treatment of congenital junctional ectopic tachycardia

Resumen La taquicardia ectópica de la unión en su variante congénita es una taquiarritmia pediátrica poco frecuente, que por su naturaleza incesante y su refractariedad a los agentes farmacológicos tradicio nales lleva asociada una alta morbimortalidad. Se presentan los casos clínicos de dos pacientes pediátricos con diagnóstico de taquicardia ectópica de la unión congénita, que mostraron respuesta inadecuada a las alternativas de tratamiento habituales y que, en consecuencia, desarrollaron miocardiopatía dilatada y disfunción ventricular secundaria a la taquicardia sostenida. En ambos se utilizó ivabradina como alternativa farmacológica innovadora pare el control de ésta con excelente respuesta clínica.

Abstract The congenial form of junctional ectopic tachycardia is a rare variant of pediatric tachyarrhythmia that due to its incessant nature and its refractoriness to the traditionally used antiarrhythmic agents has a high morbimortality The clinical cases of two patients with a diagnosis of congenital junctional ectopic tachycardia with inadequate response to the regular pharmacological options, who developed dilated cardiomyopathy and ventricular dysfunc tion secondary to sustained tachycardia, are presented. In both ivrabadine, a new innovative option was used with excellent clinical response.

[Use of ivabradine for the treatment of congenital junctional ectopic tachycardia]. / Uso de la ivrabadina para el tratamiento de la taquicardia ectópica de la unión congénita.

The congenial form of junctional ectopic tachycardia is a rare variant of pediatric tachyarrhythmia that due to its incessant nature and its refractoriness to the traditionally used antiarrhythmic agents has a high morbimortality The clinical cases of two patients with a diagnosis of congenital junctional ectopic tachycardia with inadequate response to the regular pharmacological options, who developed dilated cardiomyopathy and ventricular dysfunction secondary to sustained tachycardia, are presented. In both ivrabadine, a new innovative option was used with excellent clinical response.

La taquicardia ectópica de la unión en su variante congénita es una taquiarritmia pediátrica poco frecuente, que por su naturaleza incesante y su refractariedad a los agentes farmacológicos tradicionales lleva asociada una alta morbimortalidad. Se presentan los casos clínicos de dos pacientes pediátricos con diagnóstico de taquicardia ectópica de la unión congénita, que mostraron respuesta inadecuada a las alternativas de tratamiento habituales y que, en consecuencia, desarrollaron miocardiopatía dilatada y disfunción ventricular secundaria a la taquicardia sostenida. En ambos se utilizó ivabradina como alternativa farmacológica innovadora pare el control de ésta con excelente respuesta clínica.

Mejora progresiva de los umbrales de captura auricular y ventricular, detección e impedancias en los cables de estimulación epicárdica en adultos jóvenes que se someten a conversión de Fontan. / Progressive improvement of atrial and ventricular capture thresholds, sensing, and impedances in epicardial pacing leads in young adults undergoing Fontan conversion.

OBJECTIVES: Patients with univentricular hearts who require permanent pacing systems typically require placement of epicardial leads. It is frequently difficult to find a position with good thresholds due to epimyocardial fibrosis or fat. The goal of the study is to assess the progression of capture thresholds (CT), sensing parameters (P waves and R waves), and impedances (imp) of steroid eluting epicardial pacing leads in young adults who underwent Fontan conversion and a pacemaker implant. METHODS: All patients undergoing Fontan conversion in two institutions were retrospectively identified. Demographic data, congenital heart defects, pacing leads used, and pacing parameters were analyzed at implant, at 6 weeks and 12 months after implant. RESULTS: Twenty patients were identified (twelve males); mean age at conversion was 24.9 ± 5.4 years (range 18-35). Epicardial bipolar steroid eluting leads were used. The site of implant both in the atria and the ventricles varied depending on the parameters. At implant, mean atrial and ventricular impedances were 617 ± 171 Ω and 1061 ± 771 Ω, respectively, mean P wave amplitude was 2 ± 0.7 mV, and mean R wave amplitude was 12.5 ± 7.7 mV. Mean CT was 1.7 ± 0.8 V at 0.5 ms for the atrium and 2.2 ± 1.2 V at 0.5 ms for the ventricle. Ventricular CT and impedance showed an improvement within the first 12 months after implant, with four patients having a decrease in threshold of more than 2 V. CONCLUSION: In patients undergoing Fontan conversion, implant ventricular CT and impedances are frequently higher than expected but typically improve during follow-up. Acceptance of higher initial threshold values may be a potential strategy in this patient population.

OBJETIVO: Los pacientes con corazón univentricular que requieren estimulación cardíaca reciben sistemas de estimulación epicárdicos. Debido a la presencia de fibrosis o grasa epi-miocárdica es dificultoso en esta población encontrar sitios con adecuados parámetros de estimulación. El objetivo de este estudio es determinar la progresión de los umbrales de captura, los parámetros de sensado (medición de las ondas P y R) e impedancias (imp) de los catéteres epicárdicos con liberación de esteroides implantados en adultos jóvenes sometidos a cirugía de reconversión de Fontan e implante de marcapasos. MÉTODOS: Los pacientes sometidos a cirugía de reconversión de Fontan en dos instituciones fueron analizados retrospectivamente. Los datos demográficos, el tipo de cardiopatía congénita, de catéteres de estimulación y los parámetros de estimulación fueron analizados al momento del implante, a las 6 semanas y al año. RESULTADOS: Se identificaron 20 pacientes (12 de ellos de sexo masculino); la edad media al momento de la reconversión fue de 24.9 ± 5.4 años (rango 18-35). Se utilizaron catéteres epicárdicos bipolares de fijación pasiva y con liberación de esteroides en todos los casos. El sitio de implante en las aurículas y en los ventrículos fue variable de acuerdo a los parámetros. En el momento del implante las impedancias medias fueron 617 ± 171 W y 1061 ± 771 W respectivamente, la amplitud media de la onda P fue 2 ± 0.7 mV y la media de amplitud de la onda R fue de 12.5 ± 7.7 mV. Las medias de los umbrales de captura fueron 1.7 ± 0.8 V at 0.5 ms para los catéteres auriculares y 2.2 ± 1.2 V at 0.5 ms para los ventriculares. Los umbrales de captura y las impedancias ventriculares mostraron una mejoría en los 12 meses posteriores al implante, y en 4 pacientes esa mejoría en el umbral de captura ventricular fue mayor a 2 V. CONCLUSIONES: En pacientes sometidos a una cirugía de reconversión de Fontan e implante de marcapasos, los umbrales de captura e impedancias ventriculares son más elevados que los esperados, pero mejoran durante el seguimiento. La aceptación de valores más elevados puede potencialmente constituir una alternativa en esta población de pacientes.

Disincronía ventricular inducida por fármacos y taquicardiomiopatía en un neonate / Drug-induced ventricular dissynchrony and tachycardiomyopathy in a newborn

Resumen La disfunción ventricular secundaria a disincronía eléctrica y mecánica es una complicación de la estimulación ventricular desde el ápex del ventrículo derecho. No existen informes de disincronía secundaria a los efectos de fármacos antiarrítmicos. Se presenta el caso de una niña de 10 días de vida con taquicardia supraventricular incesante que se internó en terapia intensiva neonatal. Se inició tratamiento con propranolol por vía oral y ante la persistencia de la taquicardia se agregó amiodarona endovenosa. La paciente estuvo predominantemente en taquicardia con frecuencias cardíacas entre 200 y 290 latidos por minuto durante una semana a pesar del tratamiento instaurado. La función ventricular fue normal en los ecocardiogramas realizados. Se agregó flecainida por vía oral al esquema de tratamiento y luego de 24 horas presentó una taquicardia más lenta con QRS ancho e imagen de bloqueo completo de rama izquierda. Un nuevo ecocardiograma evidenció deterioro de la función ventricular izquierda e insuficiencia mitral moderada lo que motivó la suspensión de la flecainida y el propranolol. A las 24 horas de la suspensión se observó la normalización de la función ventricular a pesar de la persistencia de episodios intermitentes de taquicardia. Se reinició el propranolol logrando el control de la taquicardia. La presencia de disincronía ventricular generada por el bloqueo de rama izquierda secundario al tratamiento farmacológico con flecainida constituye una novedosa explicación posible para el desarrollo de disfunción ventricular.

Abstract Ventricular dysfunction secondary to electrical and mechanical dyssynchrony in chronic right ventricular apical pacing is a well-recognized complication. There are no previous reports of pharmacologically induced dyssynchrony. A 10-day old infant with incessant supraventricular tachycardia was admitted to the neonatal intensive care unit. Therapy with oral propranolol was initiated and due to persistence of tachycardia intravenous amiodarone was administered. The patient remained predominantly in tachycardia with heart rates between 200-290 beats per minute for a week with serial echocardiograms showing preserved ventricular function. Oral flecainide was started. After 24 hours of treatment the patient developed a slower incessant wide QRS with a left bundle branch block pattern. The echocardiogram showed deterioration of left ventricular systolic function and moderate mitral regurgitation. Flecainide and propranolol were discontinued. The QRS complex narrowed and despite intermittent breakthroughs of supraventricular tachycardia, ventricular function normalized. Propranolol was restarted to achieve definitive control of the tachycardia. The presence of ventricular dyssynchrony generated by the left bundle branch block pattern secondary to pharmacological treatment with flecainide is a novel possible explanation for the development of ventricular dysfunction.

[Drug-induced ventricular dissynchrony and tachycardiomyopathy in a newborn]. / Disincronía ventricular inducida por fármacos y taquicardiomiopatía en un neonato.

Ventricular dysfunction secondary to electrical and mechanical dyssynchrony in chronic right ventricular apical pacing is a well-recognized complication. There are no previous reports of pharmacologically induced dyssynchrony. A 10-day old infant with incessant supraventricular tachycardia was admitted to the neonatal intensive care unit. Therapy with oral propranolol was initiated and due to persistence of tachycardia intravenous amiodarone was administered. The patient remained predominantly in tachycardia with heart rates between 200-290 beats per minute for a week with serial echocardiograms showing preserved ventricular function. Oral flecainide was started. After 24 hours of treatment the patient developed a slower incessant wide QRS with a left bundle branch block pattern. The echocardiogram showed deterioration of left ventricular systolic function and moderate mitral regurgitation. Flecainide and propranolol were discontinued. The QRS complex narrowed and despite intermittent breakthroughs of supraventricular tachycardia, ventricular function normalized. Propranolol was restarted to achieve definitive control of the tachycardia. The presence of ventricular dyssynchrony generated by the left bundle branch block pattern secondary to pharmacological treatment with flecainide is a novel possible explanation for the development of ventricular dysfunction.

La disfunción ventricular secundaria a disincronía eléctrica y mecánica es una complicación de la estimulación ventricular desde el ápex del ventrículo derecho. No existen informes de disincronía secundaria a los efectos de fármacos antiarrítmicos. Se presenta el caso de una niña de 10 días de vida con taquicardia supraventricular incesante que se internó en terapia intensiva neonatal. Se inició tratamiento con propranolol por vía oral y ante la persistencia de la taquicardia se agregó amiodarona endovenosa. La paciente estuvo predominantemente en taquicardia con frecuencias cardíacas entre 200 y 290 latidos por minuto durante una semana a pesar del tratamiento instaurado. La función ventricular fue normal en los ecocardiogramas realizados. Se agregó flecainida por vía oral al esquema de tratamiento y luego de 24 horas presentó una taquicardia más lenta con QRS ancho e imagen de bloqueo completo de rama izquierda. Un nuevo ecocardiograma evidenció deterioro de la función ventricular izquierda e insuficiencia mitral moderada lo que motivó la suspensión de la flecainida y el propranolol. A las 24 horas de la suspensión se observó la normalización de la función ventricular a pesar de la persistencia de episodios intermitentes de taquicardia. Se reinició el propranolol logrando el control de la taquicardia. La presencia de disincronía ventricular generada por el bloqueo de rama izquierda secundario al tratamiento farmacológico con flecainida constituye una novedosa explicación posible para el desarrollo de disfunción ventricular.

Experiencia en el uso de propranolol para el tratamiento de la taquicardia supraventricular en pacientes menores de un año / Experience using propranolol for the management of supraventricular tachycardia in patients younger than 1 year

Objetivo. Evaluar los resultados y efectos adversos de la terapia con propranolol en menores de un año con taquicardia supraventricular. Población y métodos. Menores de 1 año con taquicardia supraventricular documentada, que recibieron tratamiento y prevención con propranolol por vía oral. Se analizaron sexo y edad, cardiopatía congénita asociada, pre excitación ventricular en el electrocardiograma basal, recurrencia intratratamiento y efectos adversos. Resultados. Se identificaron 107 pacientes. El primer episodio de taquicardia supraventricular ocurrió a una edad mediana de 190 días. En 10 pacientes, se observó cardiopatía congénita asociada. El 23,3 % presentó pre excitación ventricular en el electrocardiograma basal. El rango de la dosis de propranolol fue de 2 a 5 mg/kg/día. En el 30,8 %, se observó recurrencia intratratamiento. En 2 pacientes, se suspendió la medicación por efectos adversos graves. Conclusión. El propranolol evitó la recurrencia en el 70 % de los casos. En 2 pacientes, fue necesario suspenderlo por efectos adversos graves

Objective. To assess the results and adverse events of propranolol therapy in infants younger than 1 year with supraventricular tachycardia. Population and methods. Infants younger than 1 year with documented supraventricular tachycardia who received oral treatment and prophylaxis with propranolol. Sex and age, associated congenital heart disease, ventricular preexcitation in the base line electrocardiogram, on-treatment recurrence, and adverse events were analyzed. Results. A total of 107 patients were identified. The first supraventricular tachycardia event occurred at a median age of 190 days. Associated congenital heart disease was observed in 10 patients. Ventricular preexcitation in the baseline electrocardiogram was detected in 23.3 %. Propranolol dose ranged from 2 to 5 mg/kg/day. On-treatment recurrence was observed in 30.8 %. Medication was discontinued in 2 patients due to severe adverse events. Conclusion. Propranolol prevented recurrence in 70 % of cases. It was discontinued in 2 patients due to severe adverse events.

Experience using propranolol for the management of supraventricular tachycardia in patients younger than 1 year. / Experiencia en el uso de propranolol para el tratamiento de la taquicardia supraventricular en pacientes menores de un año.

OBJECTIVE: To assess the results and adverse events of propranolol therapy in infants younger than 1 year with supraventricular tachycardia. POPULATION AND METHODS: Infants younger than 1 year with documented supraventricular tachycardia who received oral treatment and prophylaxis with propranolol. Sex and age, associated congenital heart disease, ventricular preexcitation in the base line electrocardiogram, on-treatment recurrence, and adverse events were analyzed. RESULTS: A total of 107 patients were identified. The first supraventricular tachycardia event occurred at a median age of 190 days. Associated congenital heart disease was observed in 10 patients. Ventricular preexcitation in the baseline electrocardiogram was detected in 23.3 %. Propranolol dose ranged from 2 to 5 mg/kg/day. On-treatment recurrence was observed in 30.8 %. Medication was discontinued in 2 patients due to severe adverse events. CONCLUSION: Propranolol prevented recurrence in 70 % of cases. It was discontinued in 2 patients due to severe adverse events.

Objetivo. Evaluar los resultados y efectos adversos de la terapia con propranolol en menores de un año con taquicardia supraventricular. Población y métodos. Menores de 1 año con taquicardia supraventricular documentada, que recibieron tratamiento y prevención con propranolol por vía oral. Se analizaron sexo y edad, cardiopatia congènita asociada, pre excitación ventricular en el electrocardiograma basal, recurrencia intratratamiento y efectos adversos. Resultados. Se identificaron 107 pacientes. El primer episodio de taquicardia supraventricular ocurrió a una edad mediana de 190 días. En 10 pacientes, se observó cardiopatia congènita asociada. El 23,3 % presentó pre excitación ventricular en el electrocardiograma basal. El rango de la dosis de propranolol fue de 2 a 5 mg/kg/día. En el 30,8 %, se observó recurrencia intratratamiento. En 2 pacientes, se suspendió la medicación por efectos adversos graves. Conclusión. El propranolol evitó la recurrencia en el 70 % de los casos. En 2 pacientes, fue necesario suspenderlo por efectos adversos graves.

The HAV pattern in pediatric patients with atrioventricular node reentrant tachycardia.

OBJECTIVES: The purpose of this study is to assess the prevalence of a His-Atrial-Ventricular (HAV) pattern, i.e. the atrial electrogram following the His bundle -HB- electrogram and preceding the ventricular one, on the catheter placed in the His position in pediatric patients during typical atrioventricular node reentry (AVNRT). MATERIALS AND METHODS: The pediatric electrophysiology databases of two separate institutions were queried for patients with a diagnosis of AVNRT. Demographic, clinical data and the electrophysiology study (EPS) information were assessed. RESULTS: Thirty-nine consecutive patients were included. Twenty-five were female. The average age at the time of the EPS was 12 ± 3.7 years. Induction was achieved with atrial pacing in 23, with a single atrial extra stimulus in 8 and with dual atrial extra stimuli in 8. Isoproterenol was needed to induce tachycardia in 21. Tachycardia cycle length averaged 320 ± 50 ms. An HAV pattern was present in 35 (74%) of the patients, and in 100% of the patients younger than 8. CONCLUSIONS: An HAV pattern on the catheter placed in the His position, is common in pediatric patients with AVNRT, occurring in up to 74% of the patients in this population, being more common in younger patients.

Características electrocardiográficas de vías fascículo-ventriculares en pediatría: estudio comparativo con las vías accesorias anteroseptalesderechas / Electrocardiographic characteristics of fasciculo-ventricular accessory pathways in children: A comparative study with right anteroseptal accessory pathways

Resumen Objetivos: Las vías accesorias (VAc) fascículo-ventriculares (FV) tienen una localización anatómica similar a las VAcanteroseptales derechas (ASD) y comparten características electrocardiográficas. El objetivo es comparar características electrocardiográficas de las VAC FV con las de las ASD en pediatría. Métodos: Se incluyeron pacientes con preexcitación manifiesta sometidos a estudio electrofisiológico. Las VAc FV se definieron por un intervalo HV ≤ 32ms y un alargamiento del AH sin modificación del HV, del grado o patrón de preexcitación ventricular durante la estimulación auricular. Tres observadores independientes y ciegos analizaron los ECG en cada grupo. Resultados: De 288 pacientes, 15 (5.2%) presentaban VAC FV y 14 VAC ASD (4.9%). El intervalo PR fue más largo en las VAc FV que en las ASD (113 ± 21 vs. 86 ± 13 ms respectivamente; p = < 0.001) y la duración del QRS fue menor (95 ± 12 vs. 137 ± 24 ms respectivamente; p = < 0.001). El ECG de las VAc FV presentó una deflexión rápida de baja amplitud previa al inicio del QRS en 13 de 15 pacientes (87%) y en 2 con VAc AV ASD (14%); (p = 0.003). Conclusiones: El intervalo PR fue más largo y el complejo QRS más angosto en la VAC FV respecto de las ASD. La presencia de una deflexión rápida de baja amplitud previa al inicio del QRS permitiría diferenciarlas de las aurículo-ventriculares ASD de manera no invasiva.

Abstract Objectives: Fasciculo-ventricular (FV) accessory pathways (AP's) and right anteroseptal (RAS) AP's share similar anatomic locations and electrocardiographic characteristics. The objective of this article is to compare these features in children. Methods: All patients with manifest pre-excitation who underwent an electrophysiological study were included. Fasciculo-ventricular AP's were defined by the presence of an HV inter- val ≤ 32 ms and a prolongation of the AH without changes in the HV interval, or the level of pre-excitation during atrial pacing. Three independent and blind observers analysed the ECG's in both groups. Results: Out of 288 patients, 15 (5.2%) had FV AP's and 14 (4.9%) right AS AP's. The PR interval was longer in FV AP's than in RAS (113 ± 21 vs 86 ± 13 ms respectively; P < .001) and the QRS was narrower (95 ± 12 vs 137 ± 24 ms respectively; P < .001). The ECG in patients with FV AP's showed a rapid low amplitude deflection at the begining of the QRS in 13 out of 15 patients (87%) and in 2 (14%) the RAS AP group (P = .003). Conclusions: The PR interval was longer and the QRS complex was narrower in patients with FV AP's. The presence of a rapid low amplitude deflection at the beginning of the QRS complex would allow to differentiate them from RAS AP's non-invasively.

Arrhythmias in congenital heart disease: a position paper of the European Heart Rhythm Association (EHRA), Association for European Paediatric and Congenital Cardiology (AEPC), and the European Society of Cardiology (ESC) Working Group on Grown-up Congenital heart disease, endorsed by HRS, PACES, APHRS, and SOLAECE.

The population of patients with congenital heart disease (CHD) is continuously increasing with more and more patients reaching adulthood. A significant portion of these young adults will suffer from arrhythmias due to the underlying congenital heart defect itself or as a sequela of interventional or surgical treatment. The medical community will encounter an increasing challenge as even most of the individuals with complex congenital heart defects nowadays become young adults. Within the past 20 years, management of patients with arrhythmias has gained remarkable progress including pharmacological treatment, catheter ablation, and device therapy. Catheter ablation in patients with CHD has paralleled the advances of this technology in pediatric and adult patients with structurally normal hearts. Growing experience and introduction of new techniques like the 3D mapping systems into clinical practice have been particularly beneficial for this growing population of patients with abnormal cardiac anatomy and physiology. Finally, device therapies allowing maintanence of chronotropic competence and AV conduction, improving haemodynamics by cardiac resynchronization, and preventing sudden death are increasingly used. For pharmacological therapy, ablation procedures, and device therapy decision making requires a deep understanding of the individual pathological anatomy and physiology as well as detailed knowledge on natural history and long-term prognosis of our patients. Composing expert opinions from cardiology and paediatric cardiology as well as from non-invasive and invasive electrophysiology this position paper was designed to state the art in management of young individuals with congenital heart defects and arrhythmias.

[Electrocardiographic characteristics of fasciculo-ventricular accessory pathways in children: A comparative study with right anteroseptal accessory pathways]. / Características electrocardiográficas de vías fascículo-ventriculares en pediatría: estudio comparativo con las vías accesorias anteroseptales derechas.

OBJECTIVES: Fasciculo-ventricular (FV) accessory pathways (AP's) and right anteroseptal (RAS) AP's share similar anatomic locations and electrocardiographic characteristics. The objective of this article is to compare these features in children. METHODS: All patients with manifest pre-excitation who underwent an electrophysiological study were included. Fasciculo-ventricular AP's were defined by the presence of an HV interval≤32ms and a prolongation of the AH without changes in the HV interval, or the level of pre-excitation during atrial pacing. Three independent and blind observers analysed the ECG's in both groups. RESULTS: Out of 288 patients, 15 (5.2%) had FV AP's and 14 (4.9%) right AS AP's. The PR interval was longer in FV AP's than in RAS (113±21 vs 86±13ms respectively; P<.001) and the QRS was narrower (95±12 vs 137±24ms respectively; P<.001). The ECG in patients with FV AP's showed a rapid low amplitude deflection at the begining of the QRS in 13 out of 15 patients (87%) and in 2 (14%) the RAS AP group (P=.003). CONCLUSIONS: The PR interval was longer and the QRS complex was narrower in patients with FV AP's. The presence of a rapid low amplitude deflection at the beginning of the QRS complex would allow to differentiate them from RAS AP's non-invasively.

[An apparent life threatening secondary to long Qt syndrome]. / Aparente amenaza para la vida por el síndrome de QT prolongado.

We report the case of an infant with an episode of loss of consciousness, in whom ventricular fibrillation was diagnosed. He was successfully defibrillated and long QT syndrome was diagnosed as his baseline disease. This case constitutes a documented example of this entity as a cause of the sudden infant death syndrome.

Aparente amenaza para la vida por el síndrome de QT prolongado / An apparent life threatening secondary to long Qt syndrome

Se presenta el caso de un lactante con un episodio de pérdida de conocimiento, en quien se diagnosticó fibrilación ventricular. Se realizó desfibrilación externa con éxito, permitiendo luego arribar al diagnóstico etiológico de síndrome de QT prolongado, constituyendo un ejemplo documentado de esta entidad como causa del síndrome de muerte súbita del lactante.(AU)

We report the case of an infant with an episode of loss of consciousness, in whom ventricular fibrillation was diagnosed. He was successfully defibrillated and long QT syndrome was diagnosed as his baseline disease. This case constitutes a documented example of this entity as a cause of the sudden infant death syndrome.(AU)

Aparente amenaza para la vida por el síndrome de QT prolongado / An apparent life threatening secondary to long Qt syndrome

Se presenta el caso de un lactante con un episodio de pérdida de conocimiento, en quien se diagnosticó fibrilación ventricular. Se realizó desfibrilación externa con éxito, permitiendo luego arribar al diagnóstico etiológico de síndrome de QT prolongado, constituyendo un ejemplo documentado de esta entidad como causa del síndrome de muerte súbita del lactante.

We report the case of an infant with an episode of loss of consciousness, in whom ventricular fibrillation was diagnosed. He was successfully defibrillated and long QT syndrome was diagnosed as his baseline disease. This case constitutes a documented example of this entity as a cause of the sudden infant death syndrome.

Fascicular and nonfascicular left ventricular tachycardias in the young: an international multicenter study.

INTRODUCTION: The aim of this study was to evaluate the clinical presentation and outcomes of pediatric patients with ventricular tachycardia (VT) originating from left heart structures. METHODS AND RESULTS: This international multicenter retrospective study including 152 patients (age 10.0 ± 5.1 years, 62% male), divided into those with fascicular VT (85%, 129/152) and nonfascicular LV VT (15%, 23/152). All patients had a normal heart structure or only a minor cardiac abnormality. Adenosine was largely ineffective in both groups (tachycardia termination in 4/74 of fascicular VT and 0/5 of nonfascicular LV VT). In fascicular VT, calcium channel blockers were effective in 80% (74/92); however, when administered orally, there was a 21% (13/62) recurrence rate. In nonfascicular LV VT, a variety of antiarrhythmic therapies were used with no one predominating. Ablation procedures were successful in 71% (72/102) of fascicular VT and 67% (12/18) of nonfascicular LV VT on an intention to treat analysis. Major complications occurred in 5 patients with fascicular VT and 1 patient with nonfascicular LV VT. After a follow-up period of 2 years (1 day to 15 years), 72% of all patients with fascicular VT were off medications with no tachycardia recurrence. One patient died of noncardiac causes. In nonfascicular LV VT, follow-up was 3.5 years (0.5-15 years), P = 0.38. A total of 65% of these patients were free from arrhythmias. Two patients died suddenly (P < 0.01). CONCLUSION: The clinical course and outcomes of pediatric patients with fascicular VT and nonfascicular LV VT are varied. Catheter ablation procedures can be curative.

Aparente amenaza para la vida por el síndrome de QT prolongado. / [An apparent life threatening secondary to long Qt syndrome].

We report the case of an infant with an episode of loss of consciousness, in whom ventricular fibrillation was diagnosed. He was successfully defibrillated and long QT syndrome was diagnosed as his baseline disease. This case constitutes a documented example of this entity as a cause of the sudden infant death syndrome.