[Cardiac arrhythmias in adults with congenital heart disease]. / Herzrhythmusstörungen bei Erwachsenen mit angeborenen Herzfehlern.

In patients with congenital heart disease, cardiac arrhythmias are complex and require a thorough understanding of the anatomy, past surgical and interventional procedures, and the specific electric processes. Supraventricular tachycardias commonly present as emergency situations and should be treated immediately, particularly when there is an underlying complex malformation. Establishing sinus rhythm is usually superior to pure frequency control for hemodynamic reasons. Catheter ablation should be preferred over medical treatment, even though several procedures are often necessary. In addition, bradycardia is seen more frequently in congenital heart defects; this could be aggravated by antiarrhythmic drugs. There are significant differences between the indications and techniques used for pacemaker implantation in patients with congenital heart defects and those without. Patients with complex congenital heart diseases have an increased risk of thromboembolism; therefore, an individual and early indication for low-threshold oral anticoagulation is necessary; direct oral anticoagulants can also be used for this purpose. In risk stratification for sudden cardiac death, the principles of general guidelines are often not applicable, and individualized decisions are required. Recently, a new general risk score for congenital heart disease has been developed. The treatment of cardiac arrhythmias in patients with congenital heart disease should always be performed in close cooperation with specialized centers.

[Reversible severe cardiomyopathy caused by a slow permanent tachycardia]. / Reversible, schwere Kardiomyopathie als Folge einer langsamen, permanenten Schmalkomplextachykardie.

Incessant narrow QRS complex tachycardias may result in severe tachycardia-induced cardiomyopathy even if the heart rate during tachycardia is only moderately elevated. The risk of ventricular deterioration is particularly increased in patients with underlying congenital heart disease. In these patients, drug treatment is often insufficient. Thus, catheter ablation of the arrhythmogenic substrate is required in the majority of patients. After successful ablation, ventricular function may recover completely.

Percutaneous pulmonary valve implantation (PPVI) in non-obstructive right ventricular outflow tract: limitations and mid-term outcomes.

BACKGROUND: Percutaneous pulmonary valve implantation (PPVI) has been established as a safe and effective alternative to surgery treating patients with a failing pulmonary valve conduit. Nevertheless, the majority of patients in need of a valve have a native, non-obstructive right ventricular outflow tract (RVOT). The current approved stent-valves have a balloon-expandable design. Pre-stenting of the RVOT to create a landing zone and also protect the valve stability is usually mandatory; large, non-obstructive RVOTs need pre-stenting to reduce the RVOT-diameter for a balloon-expandable valve implantation. METHODS: A retrospective study design was used to analyze the medium-term outcome after PPVI in a series of 26 patients with native or reconstructed RVOT. RESULTS: PPVI was successfully performed in all, but 1 (96%). Within the follow-up of a minimum of 2 years, the percutaneous implanted valves remained competent; a significant pressure gradient was not detected. Furthermore, no PPVI-related complications such as endocarditis, migration or stent fractures were observed. The electrocardiogram at rest, in particular the QRS duration remained unchanged immediate post-PPVI as well as at medium-term follow-up of 24 months. However, ventricular arrhythmias were documented in 3 patients (11.5%); all patients were successfully treated with antiarrhythmic drugs, utilizing metoprolol. A trial of an invasive catheter based RVOT-ablation in one remained unsuccessful; pre-stented RVOT did not allow a successful intervention. CONCLUSIONS: Medium-term follow-up showed excellent results of the mechanical valve function. PPVI utilizing balloon-expandable stent-valves in a native RVOT remains an off-label use. Despite our encouraging results, advanced manipulations of the patched or native RVOT might be associated with significant ventricular arrhythmias. There is a need for less invasive RVOT reduction devices.

Diagnosis of tachycardia mechanism with cryomapping in a toddler with complex congenital heart disease.

A 2.5-year-old patient with complex congenital heart disease involving dextrocardia, atrioventricular and ventriculoarterial discordance, pulmonary stenosis, ventricular septal defect (VSD), atrial septal defect (ASD), and paroxysmal supraventricular tachycardia (SVT) underwent electrophysiological study. The tachycardia mechanism was diagnosed with cryomapping. The ability of cryomapping to have transient and reversible effect on the tissue, unlike radiofrequency (RF) ablation, helped in the establishment of diagnosis in this toddler with typical atrioventricular nodal reentrant tachycardia. Cryomapping can be an additional safe diagnostic utility in young patients with complex congenital heart disease.

ICD Implantation in infants and small children: the extracardiac technique.

BACKGROUND: There is no clear methodology for implantation of an internal cardioverter-defibrillator (ICD) in infants and small children. The aim of this study was to assess efficacy and safety of an extracardiac ICD implantation technique in pediatric patients. PATIENTS AND METHODS: An extracardiac ICD system was implanted in eight patients (age: 0.3-8 years; body weight: 4-29 kg). Under fluoroscopic guidance a defibrillator lead was tunneled subcutaneously starting from the anterior axillar line along the course of the 6th rib until almost reaching the vertebral column. After a partial inferior sternotomy, bipolar steroid-eluting sensing and pacing leads were sutured to the atrial wall (n = 2) and to the anterior wall of the right ventricle (n = 8). The ICD device was implanted as "active can" in the upper abdomen. Sensing, pacing, and defibrillation thresholds (DFTs) as well as impedances were verified intraoperatively and 3 months later, respectively. RESULTS: In seven of eight patients, intraoperative DFT between subcutaneous lead and device was <15 J. In the eighth patient ICD implantation was technically not feasible due to a DFT >20 J. During follow-up (mean 14.5 months) appropriate and effective ICD discharges were noted in two patients. DFT remained stable after 3 months in four of six patients retested. A revision was required in one patient due to lead migration and in another patient due to a lead break. CONCLUSIONS: In infants and small children, extracardiac ICD implantation was technically feasible. Experience and follow-up are still limited. The course of the DFT is unknown, facing further growth of the patients.