Efeitos adversos em longo prazo da sobre-estimulação atrial dinâmica em pacientes com marcapasso e doença do nó sinusal / Long-term adverse effects of dynamic atrial overstimulation in patients with pacemaker and sinus node disease

Diversos estudos têm sido realizados a fim de mostrar a eficácia dos algoritmos na redução dos episódios da fibrilação atrial (FA). Dentre eles, destaca-se o ADOPT A (Atrial Dynamic Overdrive Pacing Trial - A), com o objetivo de avaliar a eficácia de um algoritmo de overpace atrial dinâmico (DAO - dynamic atrial overdrive) na redução de episódios de fibrilação atrial. Objetivo primário: Analisar os efeitos adversos do uso em longo prazo da sobre-estimulação atrial dinâmica em portadores de marcapasso para doença do nó sinusal do tipo síndrome braditaquicardia. Objetivo secundário: Avaliar a prevalência de possíveis efeitos adversos com o algoritmo e as consequências da FA, como: acidente vascular encefálico, embolia pulmonar, alterações cardíacas e outras causas. Método: Estudo observacional, retrospectivo, descritivo, no qual foi realizada a análise dos dados dos pacientes que implantaram marcapasso com software de sobre-estimulação atrial. Critério de inclusão: portador de MP com software overdrive programado em DDD cuja indicação baseou-se na presença de doença do nó sinusal do tipo síndrome braditaquicardia, em acompanhamento por um período mínimo de 48 meses. A coleta de dados foi feita por meio de consulta ao prontuário do paciente. Resultados: No que tange aos dados telemétricos encontrados, os diagnósticos dos 20 pacientes da amostra refletiram em uma média de 79,09 ± 5,39 episódios de troca (AMS), com janela em ciclos estimulados (OPC) de 28,54 ± 9,91, respeitando uma taxa básica de estímulos já programada de acordo com a mudança de modo. A frequência básica (BR) atingiu 62,9 ± 5,16 bpm em média.

Several studies have been conducted to demonstrate the effectiveness of algorithms in reducing atrial fibrillation episodes (AF). Among them, we highlight ADOPT A (Atrial Dynamic Overdrive Pacing Trial - A), with the aim of evaluating the dynamic algorithm overpace effectiveness (DAO - dynamic atrial overdrive) in reducing atrial fibrillation episodes. Primary Objective: Analyze database looking for long-term adverse effects of DAO in patients with pacemaker for sinus disease in type bradycardia-tachycardia syndrome. Secondary Objective: Evaluate the prevalence of possible adversities with the algorithm and consequences of FA as stroke, pulmonary embolism, cardiac abnormalities and other causes. Method: The project is an observational, retrospective, descriptive trial and analyzed data of patients whose pacemaker was implanted using an atrial overstimulation software. This protocol was approved by the ethics committee of the Catholic University of Goiás on March 04, 2013, with protocol number 210 302. Inclusion criteria: patients using a pacemaker implanted by an overdrive software programmed in DDD within a minimum of four (4) years, whose indication was based on the presence of sinus node disease type bradycardia-tachycardia syndrome. Data collection was obtained by assessing the patient’s chart...

Displasia arritmogenica del ventriculo derecho y enfermedad del nodulo sinusal / Arrhythmogenic right ventricular dysplasia and sick sinus syndrome

La displasia arritmogénica del ventrículo derecho (DAVD) compromete principalmente al ventrículo derecho y debe ser considereada en pacientes jóvenes que presentan síncope, taquicardia ventricular o paro cardíaco y en adultos con insulficiencia cardíaca congestiva. Las alteraciones eléctricas auriculares debidas a DAVD han sido poco descriptas. Informamos el caso de un varón de 60 años con DAVD que durante la evolución presentó enfermedad del nódulo sinusal (tiempo de recuperación del nódulo sinusal de 6113 mseg). Las arritmias auriculares se podrían explica® por el reemplazo gradual de los miocitos auriculares por tejido adiposo.

Clinical Characteristics of Hypervagotonic Sinus Node Dysfunction

BACKGROUND: Sinus node dysfunction (SND) is caused not only by intrinsic sinus node disease, but also by the extrinsic factors. Among the extrinsic factors, autonomic imbalance is most common. Symptomatic SND usually requires permanent pacemaker therapy. However, the clinical characteristics and patient response to medical therapy for hypervagotonic SND have not been properly clarified. MATERIALS AND METHODS: Thirty two patients (14 men, 18 women, 51 +/- 14 years) with hypervagotonic SND were included in this study, but those patients who had taken calcium antagonists, beta-blockers or other antiarrhythmic drugs were excluded. Hypervagotonic SND was diagnosed if the abnormal electrophysiologic properties of the sinus node were normalized after the administration of atropine (0.04 mg/kg). RESULTS: The presenting arrhythmias were 16 cases of sinus bradycardia (50.0%), 12 of sinus pause (37.5%), 3 of sinoatrial block (9.4%) and 1 of tachy-bradycardia (3.1%). Nine (28.1%) patients had hypertension, 7 (21.9%) smoked, 2 (6.3%) had diabetes mellitus, and 1 (3.1%) had hypercholesterolemia. Among the patients, 3 had no remarkable symptoms, 13 had dizziness, 7 had syncope, 3 had weakness and 6 had shortness of breath. Twenty five (78.1%) patients were treated with theophylline, 1 patient with tachy-bradycardia syndrome was treated with digoxin and propafenone, and 6 (18.8%) were treated with no medication. During the 43 +/- 28 month follow-up, 25 patients remained asymptomatic, but 6 who took no medication developed mild dizziness. One patient needed permanent pacemaker implantation owing to recurrent syncope despite of theophylline treatment. CONCLUSION: These results show that hypervagotonic SND has a benign course and most of the patients can be managed safely without implanting a pacemaker. (Ed note: I like the abstract. It is short and direct, as it should be.)

Flutter auricular crónico: una manifestación infrecuente de enfermedad del nódulo sinusal: caso clínico / Chronic atrial flutter as an infrequent manifestation of sick sinus syndrome: report of 1 case

We report a 41 years old female, previously operated of an atrial septal defect, presenting with a persisting atrial flutter. Sinus node dysfunction became evident during an electrophysiological study at the moment of interrupting the flutter with electrical stimulation. The patient was treated with his bundle ablation and implantation of a definitive pacemaker. After one year of follow up, she is devoid of symptoms

Comparison of atrial and VVI pacing modes in symptomatic sinus node dysfunction without associated tachyarrhythmias.

The natural course of patients with symptomatic sinus node dysfunction who did not have associated tachyarrhythmias before pacemaker implantation was compared after VVI and atrial pacemaker implantation. Between April 1981 and June 1989, forty-seven such patients (mean age 52 + 13 years) received VVI pacemakers and forty patients (mean age 54 + 13 years) received AAI or DDD pacemakers. Baseline clinical characteristics and severity of sinus node dysfunction were comparable in the two groups. Over a follow up of 10 to 96 months (mean 49.2 + 26 months), 11 (23.4%) VVI patients were in functional class II or more compared to 2 (5%) atrially paced patients (p less than 0.01). Other complication rates were also higher in the VVI group as compared to AAI group viz. atrial fibrillation (21.2% vs 2.5% p less than 0.01) and stroke (10.6% vs 2.5%) though the number of deaths (14.9% vs 10%) was not significantly different in the two groups. Two patients in atrial paced group and one patient in VVI group developed first degree heart block. There was no incidence of second or third degree heart block. Transient loss of atrial sensing occurred in 3 patients and atrial lead displacement in 2 cases, but overall incidence of lead related problems was low and comparable in both groups. Thus atrial pacing is superior to ventricular pacing in sinus node dysfunction and risk of developing high grade atrioventricular block on follow up is low.

Asociación de enfermedad del nódulo sinusal y prolapso de la válvula mitral / Association of sick sinus syndrome and mitral valve prolapse

Se presenta una paciente de 44 años con antecedentes de episodios de pérdida del conocimiento. Se le practicó estudo hemodinámico que mostró prolapso de la válvula mitral (PVM) con arterias coronarias normales. El electrocardiograma mostró bradicardia sinusal de 52 por minuto. El ecocardiograma en modo M mostró prolapso mesotelesistólico de la válvula mitral. El Holter de 24 horas mostró paros sinusales frecuentes, ritmo de escape de la unión A-V y extrasistolia ventricular frecuente. El estudio electrofisiológico mostró prolongación del tiempo de conducción sinoauricular, lo que confirmó el diagnóstico de enfermedade del nódulo sinusal. La asociación de PVM con bradiarritmias severas ha sido destacada por diversos autores. Esto nos induce a proponer que el PVM debe ser considerado entre las posibles etiologías a confirmar en pacientes con disfunción sinusal. En el presente caso se documenta dicha asociación y se postula la posibilidad de que la muerte súbita, que es la complicación más temida en el PVM pueda deberse a episodios de asistolia, en cuyo caso sería urgente la indicación de marcapasos definitivos asociados o no a un tratamiento antiarrítmico