Bloqueo auriculoventricular completo y asistolia en un niño con ataxia-telangiectasia / Complete heart block and asystole in a child with ataxia-telangiectasia

La ataxia-telangiectasia es una entidad caracterizada por un cuadro de ataxia cerebelosa progresiva, telangiectasias, defectos inmunológicos y una mayor tendencia al desarrollo de tumores malignos. La mutación genética responsable (ataxia-telangiectasia mutada) parece jugar un papel importante en la función celular normal y el remodelado cardiovascular. Se describe la aparición de una arritmia maligna en un paciente de 14 años con un diagnóstico de ataxia-telangiectasia, en remisión completa de linfoma no Hodgkin B de alto grado. Consultó en el Servicio de Urgencias Pediátricas por episodios de presíncope, y se observó, al ingresar, bloqueo auriculoventricular completo que evolucionó hacia asistolia, por lo que requirió la colocación de un marcapasos definitivo. Las dosis acumuladas de fármacos cardiotóxicos recibidos fueron de bajo riesgo. Sin embargo, es posible que esta enfermedad degenerativa crónica afecte con el tiempo al tejido de citoconducción. En la bibliografía revisada, no existen o se desconocen reportes previos de arritmias malignas en pacientes con ataxia-telangiectasia.

Ataxia-telangiectasia is a disorder characterized by cerebellar ataxia, telangiectasia, immunodeficiency, and increased predisposition to cancer susceptibility. Mutations in the ataxia telangiectasia mutated gene seem to play an important role in normal cell function and in cardiovascular remodeling. We report a case of a 14-year-old boy with ataxia-telangiectasia and high-grade B-non-Hodgkin lymphoma who remained in continuous complete remission after chemotherapy and who was admitted into our Emergency Room presenting with episodes of presyncope. At admission he presented a complete atrioventricular block that evolved into asystole and required placement of a pacemaker. Cumulative cardiotoxic drugs received were at low risk. However, it is possible that this chronic degenerative disease may affect the cardiac conduction system over time. In the reviewed literature there are no or unknown reports of ataxia-telangiectasia with malignant cardiac arrhythmias.

Clinical and Functional Outcome of Percutaneous alcohol septal ablation in Obstructive Hypertrophic Cardiomyopathy / Resultados clínicos y funcionales de la ablación septal percutánea con alcohol en la miocardiopatía hipertrófica obstructiva

background: Percutaneous septal ablation is a therapeutic option for patients with obstructive hypertrophic cardiomyopathy refrac-tory to optimal medical therapy. However, results of initial persistence and long-term safety are still controversial. Objectives: The aim of this study was to report percutaneous alcohol septal ablation technique, clinical and functional outcome, cardiovascular events and its impact on long-term follow-up. Methods: A total of 23 patients were included in the study. Functional class (FC), left ventricular outflow tract gradient before and after the procedure and long-term cardiovascular events were evaluated. results: Median follow-up was 52 months (IR 33-72). All patients were in FC III or IV prior to the procedure, under maximum tolerated medical therapy. The procedure was successful in 91% of cases, with 85% of patients currently in FC I and 15% in FC II. Baseline left ventricular outflow tract gradient decreased from 75 mmHg (95% CI 51-89) to 25 mmHg (95% CI 10-37) (p <0.003) and with Valsalva maneuver from 118 mmHg (95% CI 88-152) to 38 mmHg (95% CI 16-69) (p <0.0002), persisting in the long-term follow-up. During hospitalization, two patients presented with complete atrioventricular block requiring permanent pacemaker implantation. No cardiovascular deaths occurred during follow up. Conclusions: Alcohol septal ablation is a promising option for the treatment of a selected population with hypertrophic obstructive cardiomyopathy, generating sustained clinical and functional improvement with low incidence of events in the long-term follow up.

Bloqueo AV completo congénito: Revisión y presentación de un caso / Congenital complete av block: Review and case report

El bloqueo auriculoventricular es un retardo o interrupción del impulso eléctrico proveniente del nodo sinusal a nivel del nódulo auriculoventricular. Es congénito en uno de cada 20,000-25,000 nacidos vivos. Secundario a desarrollo embrionario anormal del nodo auriculoventricular asociado a anomalías cardiacas estructurales o por isoinmunización materna con anticuerpos que dan daño inmunológico irreversible del tejido cardiaco del feto, por inflamación y fibrosis. Los factores de mal pronóstico son: coexistencia con malformaciones cardiovasculares, insuficiencia cardiaca, frecuencia ventricular menor de 50 por min, bradicardia durante el sueño menos de 30 por min, marcapaso bajo o cambiante, QT prolongado. En asintomáticos, se recomienda seguimiento con monitoreo y ecocardiografía. Las indicaciones de marcapasos permanente son: ritmo de escape con complejos anchos, ectopia y disfunción ventricular, QT largo, cardiomegalia y auriculomegalia derecha.

The atrioventricular block is a delay or interruption of the electrical impulse from the sinusal node, to level of the auriculoventricular nodule is a congenital (BAVC), in one of every 20,000-25,000 born alive. Secondary to an abnormal embryonic development of the node AV, associated with structural cardiac abnormalities or for maternal is immunization with antibodies that cause immunological irreversible damage in the fetal heart tissue, by inflammation and subsequent fibrosis. The factors of worst prognosis are: Coexistence with cardiovascular malformations, heart failure, ventricular frequency below 50 per minute, bradycardia less than 30 per minute during sleep, pacemaker under or changing, long QT. In asymptomatic patient, it is recommended monitoring and follow-up with echocardiography. Indications for permanent pacemaker are: escape rhythm with wide complex, ectopy and ventricular dysfunction, long QT, cardiomegaly and right atrial dilatation.

Bloqueo auriculoventricular paroxístico desencadenado por estímulo vagal con síncope recurrente / Paroxysmal Atrioventricular Block by the Triggering of Vagal Stimulus with Recurrent Syncopal Episodes

El bloqueo auriculoventricular completo (BAVC) paroxístico con ECG de reposo normal es una entidad poco frecuente. Se presenta el caso de una paciente de 34 años que cursaba el segundo mes de embarazo y consultó por cuadros sincopales recurrentes. Luego de ser evaluada con ECG, eco-Doppler cardíaco, tilt test, estudio electroencefalográfico, TAC y RM de cerebro se descartó cardiopatía de base y se interpretó que se trataba de síncope neurocardiogénico. Por persistencia de los síntomas se realizó un Holter de 5 días hasta que presentó un nuevo síncope y se arribó al diagnóstico de BAVC paroxístico. Se indicó un marcapasos definitivo VDD y seis meses después persistía asintomática.

Paroxysmal complete atrioventricular block (CAVB) with normal electrocardiogram at rest is uncommon. A 34 year-old two month-pregnant woman consulted for recurrent syncope. After screening assessment with electrocardiogram, cardiac echo-Doppler, tilt test, electroencephalogram, brain computerized tomography and magnetic resonance imaging, cardiopathy was ruled out and a diagnosis of neurocardiogenic syncope was made. As symptoms persisted, a 5 day-Holter monitoring was performed until she presented a new episode of syncope and paroxysmal CAVB was diagnosed. A definite VDD pacemaker was implanted and six months later she remained free of symptoms.