Outcomes of permanent pacemakers and implantable cardioverter-defibrillators in an adult congenital heart disease population

Background: Brady- and tachyarrhythmias commonly complicate adult congenital heart disease (ACHD). Permanent pacemakers (PPMs) or implantable cardioverter-defibrillators (ICDs) are often utilised to prevent morbidity or mortality related to arrhythmia, but can also be associated with significant morbidity themselves. Methods: We analysed outcomes from patients in our comprehensive ACHD database who were seen at least twice since 2000 and once since 2018. Of 1953 ACHD patients, 134 had a PPM and 78 had an ICD (47 for primary and 31 for secondary prevention). Results: For PPM patients, 41% had a pacing percentage below 33%, 13% had 33-66%, and 46% had above 66%. One fifth required PPM upgrade, most to cardiac resynchronisation therapy, the rest to ICD. There were 33 appropriate ICD shocks in 15 patients (19%) and 34 inappropriate shocks in 13 patients (17%) over a median follow up of 4.6 years (IQR 0.9-8.3 years). Anti-tachycardia pacing was delivered appropriately for 28% of patients and inappropriately for 9%. Apart from inappropriate therapy, one third of PPM and ICD patients had other device-related complications. Acute PPM complications included lead dysfunction requiring revision (2%), pneumothorax (2%), pleural effusion (2%) and pocket infection (2%). ICDs were also acutely complicated by lead dysfunction (4%) as well as pocket hematoma (3%). The most common long-term complication overall was lead dysfunction, affecting one sixth of both PPM and ICD patients. Finally, the rate of device insertion increased significantly with disease severity.Conclusions: Anti-arrhythmic devices can be lifesaving in ACHD patients, but inappropriate therapy and devicerelated complications are very common.