Cardiac arrhythmias in adults with congenital heart disease

Arrhythmias are a major cause of hospital admissions and morbidity in adults with congenital heart disease (CHD). Furthermore, the leading cause of death in adults with CHD is sudden cardiac death (SCD) of presumed arrhythmic aetiology. The main objectives of this thesis were to identify risk factors for the development of arrhythmias and SCD and to investigate the efficacy of several treatment strategies for these arrhythmias including pharmacological treatment and device therapy.
In-hospital arrhythmias occurred in approximately 30% of the adults undergoing surgery for CHD and were associated with a worse clinical outcome including permanent pacemaker implantation, heart failure and death. Advanced age, heart failure, significant valvular heart disease, prolonged cardiopulmonary bypass time and myocardial injury during surgery predicted in-hospital arrhythmias. In adults with CHD and first-onset of supraventricular tachycardias (SVT), class III anti-arrhythmic drugs were most effective in preserving sinus rhythm after conversion to normal sinus rhythm compared to all other oral anti-arrhythmic drugs.
Several risk factors for SCD in adults with CHD were identified and included documented prior SVTs, increased QRS duration, QT dispersion and moderately to severely impaired systolic function of the systemic and/or subpulmonic ventricle. Implantable cardioverter defibrillators were effective for the primary and secondary prevention of SCD. An easily applicable risk score model to calculate the absolute annual risk of SCD among adults with various cardiac defects was developed and validated. By means of this risk score model the patient’s individual risk for SCD can be assessed and may give the opportunity to prevent SCD.