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.

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.

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.

[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.

Use of a cardioselective beta-blocker for pediatric patients with prolonged QT syndrome.

The data on the efficacy of atenolol for long-QT syndrome (LQTS) are controversial. This study aimed to evaluate the efficacy of atenolol for pediatric patients with LQTS. A retrospective observational study investigating all patients who had LQTS treated with atenolol at two institutions was performed. The study identified 57 patients (23 boys and 34 girls) with a mean QT corrected for heart rate (QTc) of 521 ± 54 ms. The mean age of these patients at diagnosis was 9 ± 6 years. Their clinical manifestations included no symptoms (n = 33, 58%), ventricular tachycardia (n = 10, 18%), syncope (n = 6, 10%), resuscitated sudden cardiac death (n = 4, 7%), atrioventricular block (n = 2, 4%), and bradycardia or presyncope (n = 2, 3%). Of the 57 patients, 13 (22%) had a family history of sudden death. The follow-up period was 5.4 ± 4.5 years. Atenolol at a mean dose of 1.4 ± 0.5 mg/kg/day was administered twice a day for all the patients. The mean maximum heart rate was 132 ± 27 bpm on Holter monitors and 155 ± 16 bpm on exercise treadmill tests, with medication doses titrated up to achieve a maximum heart rate lower than 150 bpm on both tests. During the follow-up period, one patient died (noncompliant with atenolol at the time of death), and the remaining patients had no sudden cardiac death events. Four patients (8%) had recurrent ventricular arrhythmias, three of whom received an implantable cardioverter defibrillator (all symptomatic at the time of diagnosis). For three patients (6%), it was necessary to rotate to a different beta-blocker because of side effects or inadequate heart rate control. Atenolol administered twice daily constitutes a valid and effective alternative for the treatment of pediatric patients with LQTS.

[Congenital junctional ectopic tachycardia. Pharmacologic management during infancy]. / Taquicardia ectópica congénita de la unión. Tratamiento farmacológico en el primer año de vida.

Congenital junctional ectopic tachycardia (JET) is a rare arrhythmia that can be refractory to medical therapy with high morbidity and mortality rates. The aim of this study was to report our experience with pharmacologic management of congenital JET in infants. Seven patients with congenital JET were identified between 2008 and 2010. Only two of them presented dilated cardiomyopathy. There were no congenital structural defects. Amiodarone was given to all the patients, as single therapy in one, and in combination with propranolol in four. In one patient flecainide was administered together with amiodarone and propranolol, and in another patient was used combined with amiodarone. During follow- up with an average time of 12.2 months (median 9.75 months, range 1-28 months), sinus rhythm alternating with slow junctional tachycardia was successfully achieved in 3 patients; no side effects were detected. There was only one death in our study group. The combination of different antiarrhythmics (amiodarone plus propranolol, and eventually flecainide) is a valid option for rhythm control and management of JET in infants.

Epicardial automatic implantable cardiac defibrillator in a child with symptomatic bugada syndrome.

An 18 month old 14 kg male with symptomatic Brugada syndrome underwent placement of an epicardial automatic implantable cardiac defibrillator using a single coil transvenous lead sutured to the anterolateral aspect of the left ventricle.

[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.

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.

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.

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.

[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.

[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.

Purulent pericarditis caused by group a streptococcus.

Purulent pericarditis is a rare disease that is most often caused by organisms such as Staphylococcus aureus, Streptococcus pneumoniae, viridans streptococci, Haemophilus influenzae, and anaerobic bacteria. We present an unusual case of purulent pericarditis caused by Streptococcus pyogenes, Lancefield group A streptococcus (GAS), and we provide a review of the literature.

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.

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.

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.

Intraoperative radiofrequency ablation of the atrium: effectiveness for treatment of supraventricular tachycardia in congenital heart surgery.

BACKGROUND: Supraventricular tachycardia (SVT) is common in surgical patients with congenital heart disease. Ablation and maze operations have been shown to be effective in treating SVT, but these procedures can be complex and time-consuming because of variable anatomy and a thickened right atrium. To simplify and shorten these procedures, we used a long, flexible radiofrequency probe capable of producing long ablation lines quickly and effectively. We report the initial results with this procedure. METHODS: Six patients aged 6 weeks to 40 years with refractory SVT were referred for reoperation for repair of complex congenital heart disease (transposition of the great vessels, Ebstein's anomaly, single ventricle, tetralogy of fallot). Intraoperative radiofrequency ablation was performed in the right atrium for refractory SVT as an adjunct to surgical reconstruction (redo Fontan, right atrial reduction plasty, right ventricular outflow tract reconstruction, tricuspid repair). Lesions were made with a radiofrequency probe using temperatures of 70 degrees C for 60 seconds. Lesions were placed between the coronary sinus and the tricuspid valve, between the tricuspid valve and the inferior vena cava, between the atrial septal defect and the superior and inferior vena cava in patients with intraatrial reentry tachycardia/atrial flutter, and at the location of the accessory pathway in a patient with Wolff-Parkinson-White syndrome. The long, flexible probe has multiple independently controlled segments allowing ablation lesions that conform to the atrial morphology. RESULTS: An average of five intraoperative radiofrequency ablation lesions per patient were made. Average time for ablation was 14 minutes. With up to 25 months' follow-up, 5 patients are in sinus rhythm, and 1 is in a paced atrial rhythm. The patient with Wolff-Parkinson-White syndrome showed no preexcitation after operation. No complications resulting from intraoperative radiofrequency ablation were encountered. CONCLUSIONS: Intraoperative radiofrequency ablation in the atrium is a safe, effective, and expeditious procedure for control of SVT in patients undergoing reoperation for congenital heart disease with refractory SVT.

Sinus node dysfunction associated with lithium therapy in a child.

Lithium salts have been used extensively in both adults and children during the last 30 years, for the treatment of a variety of psychiatric conditions, including bipolar disorder The cardiac side effects of lithium in adult patients have been well described. However, to the best of our knowledge, there are no reports of lithium-induced cardiac side effects in pediatric patients. We describe the case of a 9-year-old boy who developed cardiac toxicity while receiving long-term lithium therapy.