Natural history of Brugada syndrome in a patient with congenital heart disease.

Risk stratification of sudden death in patients with Brugada syndrome (BrS) is a controversial issue, and there is currently no consensus on the best method. Examination of data from the natural history of the disease is of fundamental importance and may help to identify relatives at risk. At the same time, study of the genetic mutations responsible for the disease may also contribute to risk stratification of the syndrome, enabling identification of asymptomatic relatives carrying mutations. This paper presents the case of a young man, aged 26, monitored as a pediatric cardiology outpatient from birth for a simple structural heart defect not requiring surgery. Analysis of the evolution of the patient's electrocardiogram revealed the appearance, at the age of 20, of a pattern compatible with type I BrS. Following an episode of syncope and induction of polymorphic ventricular tachycardia in the electrophysiological study, a cardioverter-defibrillator was implanted. One year later, a single shock terminated an episode of ventricular fibrillation. A molecular study of the SCN5A gene identified a rare mutation, c.3622G>T (p.Glu1208X), recently described and associated with more severe phenotypes in patients with BrS, as in the case presented.

Spontaneous thrombosis of the ductus arteriosus.

INTRODUCTION: Spontaneous thrombus in the ductus arteriosus (DA) is a rare condition that can be the cause of potentially fatal thromboembolism. METHODS AND RESULTS: The case of a male newborn with a thrombus in the DA is described. He was treated with anticoagulation and antiplatelet therapy. Transthoracic echocardiography documented regression of the thrombus. DISCUSSION: The incidence, complications and management of this condition, which may occur in association with a DA aneurysm, are discussed. CONCLUSION: An initial medical approach, with anticoagulation and antiplatelet medication, may provide good outcomes, avoiding surgical procedures.

Percutaneous closure of perimembranous ventricular septal defects: initial experience in Portugal.

INTRODUCTION: Closure of ventricular septal defects (VSDs) with significant shunt is indicated due to the risks associated with increased pulmonary flow leading to left chamber dilatation, the possibility of cardiac dysfunction and arrhythmias, and the risk of bacterial endocarditis. Percutaneous VSD closure is an effective and safe alternative to surgery in selected patients. However, perimembranous VSD (PMVSD) constitutes a special case since the technique for percutaneous closure is more complex and hence warrants individual evaluation. OBJECTIVES: To assess the efficacy and safety of percutaneous closure of PMVSD based on the initial experience of our center, the first to use this technique in Portugal. METHODS: Five patients, aged between 5 and 23 years, with PMVSD of a suitable size for percutaneous closure, were selected since they showed evidence of a significant left-to-right shunt together with left chamber dilatation. The procedure was performed under general anesthesia, guided by fluoroscopy and transesophageal echocardiography (TEE). A femoro-femoral arteriovenous loop was established and an Amplatzer occluder implanted, the characteristics and dimensions of which were chosen according to the angiographic and TEE findings. Besides therapeutic efficacy and complications during the procedure and follow-up, left ventricular dimensions and function and degree of mitral, aortic and tricuspid regurgitation were also assessed pre- and post-procedure, during a follow-up of 5 to 23 months. RESULTS: All patients had a Qp:Qs ratio of > 2:1. In one case, the procedure was abandoned as the VSD diameter was over 17 mm, and the patient was referred for surgical closure. In the other four patients, two membranous (8 and 16 mm) and two muscular (6 and 12 mm) VSD occluders were used. On final angiographic assessment, no residual shunt was observed in any patient. One patient presented a transient junctional rhythm during the procedure. During follow-up, there was no prolongation of the PQ interval or de novo aortic regurgitation in any patient. Catheterization time ranged between 90 and 176 minutes and fluoroscopy time between 10 and 17 minutes. CONCLUSIONS: 1) Percutaneous closure of PMVSD is an effective and safe method of treatment in selected patients. 2) It is a complex procedure, but is likely to be refined and extended to a larger number of patients in suitably qualified centers.

Percutaneous catheter ablation of arrhythmias in children.

BACKGROUND: Supraventricular tachycardias (SVTs) are the most common arrhythmias in children, with Wolff-Parkinson-White (WPW) syndrome the most prevalent entity. Percutaneous catheter ablation is now the standard of care for SVT in pediatric patients, although specific techniques are required due to their age. OBJECTIVE: To evaluate the results of percutaneous catheter ablation of arrhythmias in children at our institution. METHODS: This was a retrospective study of the clinical records of patients aged 18 years who underwent electrophysiologic study and ablation between January 2002 and December 2006. The following variables were evaluated: demographic data, type of arrhythmia, associated structural heart disease, type of energy used, immediate and late success rate and incidence of complications. RESULTS: During this period, 101 procedures were performed in 97 patients aged < or = 18 years. The mean age of the patients was 15.9 +/- 2.5 years (range: 7.7-18 years), and fifty-five (56.7%) were male. The arrhythmias treated were, in decreasing order of frequency: WPW syndrome (58.4%), atrioventricular reentrant tachycardia (25.7%), atrial tachycardia (5.9%), right ventricular outflow tract (RVOT) tachycardia (5%), ventricular tachycardia (2%), atrial fibrillation (2%) and frequent extrasystoles originating in the left atrium (1%). There was associated structural heart disease in six patients. Cryoablation was performed in four cases (parahisian accessory pathways in three and anterolateral accessory pathway in one). The immediate success rate was 94.1%. The six unsuccessful cases corresponded to five with parahisian accessory pathways (the procedure was not completed due to very high risk of inducing complete atrioventricular block [AVB]) and one case of RVOT tachycardia associated with arrhythmogenic right ventricular dysplasia. There were complications in two procedures (2%): one case of right bundle branch block and one of ventricular tachycardia requiring electrical cardioversion. The mean follow-up was 17.6 months. In 87.1% of cases there was clinical and ECG success on long-term followup. Three patients (3%) required repeat procedures, and were asymptomatic in later follow-up. CONCLUSION: Percutaneous catheter ablation of arrhythmias in children proved to be a safe and effective treatment.

Atrial tachycardia ablation in a patient with double outlet right ventricle corrected by surgery.

The development of surgical and percutaneous techniques for treatment or palliation of congenital heart disease has prolonged survival in these patients and has increased late complications, particularly arrhythmias. Such arrhythmias are more frequently refractory to medical therapy, requiring percutaneous ablation. We present the clinical case of a 14-year-old child with complex congenital heart disease (double outlet right ventricle) who underwent two corrective surgeries (Rastelli operation and subsequent replacement of the homograft in the conduit connecting the right ventricle to the pulmonary artery; ventricular septal defect closure and tricuspid valve repair). After the second surgery the patient presented with wide complex syncopal tachycardia, refractory to medical therapy. Electrophysiologic study (EPS) identified an isthmus-dependent atrial flutter that was successfully treated by radiofrequency (RF) ablation (a linear block was created along the cavo-tricuspid isthmus). Three months later a new episode of tachycardia occurred, but without syncope. The second EPS revealed an atrial tachycardia originating from the lateral wall of the right atrium, which was treated by ablation with focal application of RF energy. Four months after the last EPS the child remains free of arrhythmic symptoms, under no anti-arrhythmic therapy.

[Constrictive pericarditis in children under 2 years of age]. / Pericardite constritiva nos dois primeiros anos de vida.

Two cases of constrictive pericarditis, in children under 2 years of age, of non-tuberculosis aetiology, diagnosed from June 97 to May 98 are reported. This entity is rare in paediatrics and it may progress to severe condition. Surgical treatment has a low risk and is generally associated with good prognosis. Aetiology, clinic presentation, differential diagnosis with restrictive cardiomyopathy and treatment are discussed.