Implanted Defibrillators in Young Hypertrophic Cardiomyopathy Patients: A Multicenter Study

Abstract

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease, with an annual risk of sudden cardiac death (SCD) estimated at 1 %. Limited data are available regarding both the risk of SCD in the young HCM population and the use of implantable cardioverter-defibrillators (ICDs). This retrospective study included all patients with HCM who underwent ICD implantation for primary or secondary prevention of SCD before the age of 30 years at five institutions between 1995 and 2009. There were 99 devices implanted in 73 patients. Appropriate shocks occurred for 11 % of all the patients. None of the previously identified conventional risk factors for SCD in HCM patients were associated with increased risk of appropriate shocks in the young study cohort. During a median follow-up period of 2.4 years, inappropriate shocks occurred for 22 % of the patients. Older age at implant was associated with a decreased risk of inappropriate shock. Those who underwent implantation in the earlier decade had a higher incidence of inappropriate shocks. Late complications including lead fracture or dislodgement, generator malfunction, and infection occurred for 32 % of the patients. Three patients died (4 %), one of whom had an arrhythmic sudden death. A greater proportion of primary prevention implantations was performed for patients from the latter decade. Over time, ICD use in young HCM patients has become increasingly primary prevention oriented. Shock rates mirror those reported in adult series, and there is a substantial incidence of device complications.

Risk factors for sudden cardiac death in childhood hypertrophic cardiomyopathy: A systematic review and meta-analysis

“…A significant association with SCD was shown in two univariate analyses (p<0.0001 19 , p=0.004 20 ), and one multivariable analysis (p<0.001 20 ). Kamp et al 18 described a small cohort of patients with previous ICD implantation in which a previous AE was not significant for SCD, however this study was underpowered to detect a difference. Decker et al 17 did not find an association with all CVD, however SCD was not analysed separately.…”

“…Only one study reported a statistically significant association with SCD (HR 10.6, 95%CI 1.2-90.2, p=0.03) 18 .…”

“…A family history (FHx) of sudden cardiac death (SCD) was evaluated as a risk factor in seven studies 12,[17][18][19][20]22,27 . Only one study reported a statistically significant association with SCD (HR 10.6, 95%CI 1.2-90.2, p=0.03) 18 .…”

Inappropriate ICD Shocks in Pediatric and Congenital Heart Disease Patients

“…In larger adult studies, the rate of IS has been reported to range from 10% to 15%. 16,25,27 However, most studies of ICD use in pediatric and CHD patients have found rates of IS to be between 20% and 30% in these patient populations, 10,11,13,14,[34][35][36][37][38][39][40] with some studies observing IS in up to 40% to 50% of patients and, in some instances, with inappropriate shocks being more frequent than appropriate shocks. 12,19,41,42 This is likely a result of a more active lifestyle, faster rates of sinus tachycardia, longer duration of implantation, smaller patient size, and a higher rate of device and lead complications relative to adult patients.…”

“…The use of antiarrhythmic medication has not been conclusively demonstrated to reduce the level of shock burden in this population, despite the common practice of altering medical management in patients who receive shocks. 36 However, the high baseline rate of antiarrhythmic medication use makes this a difficult association to find in the absence of a randomized trial.…”