Aims: To quantify appropriate and inappropriate therapy and complications related to implantable cardioverter-defibrillator (ICD) treatment in young patients receiving an ICD for a hereditary cardiomyopathy or channelopathy.
Methods and results: This was a retrospective study including 117 consecutive patients who had received an ICD at Aarhus University Hospital, Denmark from 1 January 1999 to 31 December 2015. Patients were followed from the date of ICD implantation until migration, death, heart transplantation, or end of follow-up on 1 February 2017. Mean age at implantation was 30.5 ± 12.8 years, and the patients were followed for a mean period of 7.1 ± 4.4 years. The cumulative incidence at 1, 5, and 10 years was 17%, 29%, and 48% for appropriate ICD therapy, 6%, 13%, and 20% for inappropriate ICD therapy, and 7%, 18%, and 33% for device-related complications, respectively. Patients with an ICD implanted for secondary prevention had a higher risk of appropriate therapy compared with patients implanted for primary prevention [adjusted hazard ratio (HR) 5.18, 95% confidence interval (CI) 2.22-12.09; P < 0.01]. There was no difference in the risk of inappropriate therapy (adjusted HR 1.58, 95% CI 0.55-4.56; P = 0.40) or device-related complications (adjusted HR 1.22, 95% CI 0.56-2.68; P = 0.62) between patients with primary and secondary preventive indication.
Conclusion: We observed high absolute risk estimates for appropriate ICD therapy in young patients with an ICD indicated by a hereditary cardiomyopathy or channelopathy. Also risks for inappropriate ICD therapy and device-related complications were significant.