Transvenous ICDs in Adolescents and Young Adults

Address reprint requests and correspondence to Michael J. Ackerman, MD, PhD, Division of Pediatric Cardiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (e-mail: ackerman.michael @mayo.edu). In the last 2 decades, the implantable cardioverterdefibrillator (ICD) has emerged as an important lifesaving cardiac device. In the past, most clinical trials involving ICDs focused primarily on the adult population. In children, population-based studies evaluating sudden death have reported an incidence of 1.3 to 8.5 per 100,000 patient-years, and many of the sudden deaths were attributed to a cardiac cause. Moreover, the survival rate for outof-hospital cardiac arrests (OHCAs) has been poor in children. Silka et al reported that pediatric patients resuscitated from sudden cardiac death are at high risk for lifethreatening arrhythmias. Therefore, the use of ICDs in young patients appears valid. However, in the past, their use in children and young patients has been limited, not only because of technical hindrances but also because of challenges faced in identifying the young person for whom ICD therapy is most appropriate. • Objective: To evaluate the indications, underlying cardiac disorders, efficacy, and complications involved with transvenous implantable cardioverter-defibrillators (ICDs) in pediatric patients at the Mayo Clinic. • Patients and Methods: The records of all patients aged 21 years or younger who underwent transvenous ICD placement at the Mayo Clinic, Rochester, Minn, were reviewed retrospectively. • Results: Between March 1992 and September 2000, 16 patients (7 females; mean age, 15.4 years; range, 10-21 years) underwent transvenous ICD placement. The ICD was implanted for primary prevention of sudden cardiac death in 7 and for secondary prevention in 9. The underlying cardiac disorders included hypertrophic cardiomyopathy in 6 patients and congenital long QT syndrome in 6 patients. The mean ± SD follow-up was 36±29 months (range, 5-108 months). There was no mortality. Seven patients (44%) received appropriate ICD therapy, including 6 of 9 who had ICDs placed for secondary prevention. ARVD = arrhythmogenic right ventricular dysplasia; DFT = defibrillation threshold; HCM = hypertrophic cardiomyopathy; ICD = implantable cardioverter-defibrillator; LQTS = long QT syndrome; OHCA = out-of-hospital cardiac arrest; QTc = corrected QT interval; VF = ventricular fibrillation Median time free from appropriate ICD discharge was 3 years (range, 0.2-9 years). Three patients (19%) experienced inappropriate ICD discharge. Two patients needed device replacement because of technical problems (lead fracture and device malfunction). Two patients developed pocket infection that required removal and reimplantation of the ICD. • Conclusion: In adolescents and young adults, transvenous ICDs may prevent sudden death but are not free of complications. Forty-four percent of this cohort received potentially life-saving ICD therapy, including two thirds who received an ICD for secondary prevention. Mayo Clin Proc. 2002;77:226-231