Long-term follow-up of implantable cardioverter-defibrillators in adult congenital heart disease patients: indications and outcomes.

Aims: Ventricular arrhythmias are a major cause of mortality in adult congenital heart disease (ACHD) patients. The European Society of Cardiology guidelines state that implantable cardioverter-defibrillators (ICD) should be considered in patients with congenital heart disease following spontaneous sustained ventricular tachycardia (VT) or cardiac arrest and in patients at presumed high risk. This study sought to analyse the circumstances in which ACHD patients received ICD and to assess outcomes of ICD implantation, including therapies delivered and the rate of complications.

Methods and results: A retrospective review was performed of all adult patients with congenital heart disease undergoing ICD implant between 2000 and 2014, in a large quaternary referral centre with over 4000 adults with congenital heart disease under active follow-up. Demographics: 42 patients with congenital heart disease had ICD implants: 55% male; age range 21-71 years and mean age 45 years. Mean age at implantation of ICD was 41 years. Mean follow-up was 5 years. Diagnosis: 50% of patients had repaired tetralogy of Fallot (TOF). Twelve per cent of patients had repaired transposition of the great arteries. Reason for ICD: 15 patients (35.7%) received ICD after sustained VT. Eleven patients (26.2%) received ICD after cardiac arrest. Sixteen (38%) had ICD implanted as primary prophylaxis. Outcome: Since implantation, six patients received an appropriate full-output shock for VT from ICD. Nineteen (45%) patients suffered significant complications (inappropriate shocks 11, inappropriate anti-tachycardia pacing resulting in VF 1, infection requiring extraction 3, lead abnormalities 3, and pneumothorax 1). Equal proportions of primary and secondary prevention patients received appropriate shocks.

Conclusions: Most patients had ICD for secondary prevention (62%), and the majority had repaired TOF. There was a 2.9% annual appropriate shock rate. However, there was a high incidence of complications with more than a third suffering a major complication (9% per annum). The risks and benefits of ICD implantation are patient and disease specific, and must be clearly discussed prior to implantation. Further research is warranted into the use of primary prevention ICD in ACHD and in alternatives to ICD such as ablation in specific patient groups.