RESUMO
Pacemaker-mediated tachycardia (PMT) remains a clinical problem in patients with dual-chamber pacemaker despite technological advances. The onset mechanism of this tachycardia is sensing of retrograde atrial activation after ventricular stimulation. Repeated retrograde conduction perpetuates tachycardia. Postventricular atrial refractory period prolongation has been used for prevention of PMT, but this is not the solution in all cases. We present a case with PMT where the retrograde limb is a left accessory pathway, which is treated with radiofrequency ablation successfully.
Assuntos
Feixe Acessório Atrioventricular/cirurgia , Estimulação Cardíaca Artificial/efeitos adversos , Ablação por Cateter , Marca-Passo Artificial/efeitos adversos , Taquicardia/cirurgia , Adulto , Feminino , Humanos , Taquicardia/diagnóstico , Resultado do TratamentoRESUMO
Pacemakers are used in small children with increasing frequency for the treatment of life-threatening bradyarrhythmias. The epicardial approach is generally preferred in these patients, to avoid the risks of vessel thrombosis. We examined the feasibility and safety of transvenous pacemaker implantation in children weighing <10 kg, via subclavian puncture, using a 4 Fr sheath introduced after a venogram was performed to evaluate the vein diameter. Progressive dilation with 5, 6, and 7 Fr sheaths preceded the insertion and placement of the endocardial lead. A subaponeurotic pocket was created in the abdominal or pectoral regions, depending upon the patient's size. Between 2001 and 2007, we treated 12 patients (median age = 16 months; range 1-32; median weight = 7.9 kg; range 2.3-10.0; 7 males), of whom four weighed <5 kg. Indications for permanent pacing included postsurgical complete atrioventricular block (n = 8), sinus node dysfunction (n = 2), congenital atrioventricular block (n = 1), and long QT syndrome (n = 1). Single-chamber pacemakers were implanted in 10, and dual-chamber pacemakers in two patients. The patients were evaluated at 48 hours, 10 days, and at 3 and 6 months. The mean follow-up was 31.8 +/- 23.5 months. There were no procedural complications. Lead dislodgment occurred in one patient and required replacement of the ventricular lead. One patient died from septicemia. Endocardial pacemaker implantation was feasible and safe in children weighing <10 kg. This procedure is less invasive than the standard epicardial approach.
Assuntos
Bradicardia/prevenção & controle , Estimulação Cardíaca Artificial/métodos , Peso Corporal , Veias Cerebrais , Pré-Escolar , Estudos de Viabilidade , Feminino , Humanos , Lactente , Recém-Nascido , MasculinoRESUMO
La finalidad de la estimulación multisitio es corregir la sincronía eléctrica y mecánica atrial y ventricular que se presenta en pacientes con fibrilación atrial paroxística (FAP) y miocardiopatía dilatada. Reportamos los dos primeros casos, en México, con estimulación biatrial para el tratamiento de la FAP, a uno se le implantó marcapaso tricameral y al otro tetracameral. El primero era un hombre joven al cual se le realizó modificación de la conducción atrioventricular con radiofrecuencia para el control de la frecuencia ventricular durante la fibrilación atrial. El segundo caso era una mujer con transposición corregida de los grandes vasos y fracción de expulsión (FE) del 30 por ciento, el cual presentaba bloqueo atrioventricular completo. El modo de estimulación fue DDD para el primer paciente y DDDR para el segundo, con función nocturna y cambio automático de modo en ambos. Se estimularon ambas aurículas, en la orejuela derecha y la izquierda a través del seno coronario. Los episodios de FAP se presentaron solamente en el primero pero en menor número y duración. La FE y la clase funcional mejoraron en el paciente con sincronización atrial y ventricular. Concluimos que la estimulación biatrial es efectiva en el control de la FAP.
