Long-Term Outcome in High-Risk Patients With Hypertrophic Cardiomyopathy After Primary Prevention Defibrillator
Ethan J Rowin1, Austin Burrows2, Christopher Madias2
1Hypertrophic Cardiomyopathy Institute (E.J.R., M.S.M., B.J.M.), Tufts Medical Center, Boston, MA.
Insights
Implantable cardioverter-defibrillators (ICDs) effectively prevent sudden death in hypertrophic cardiomyopathy patients. Long-term data shows ICD therapy increases over time, while complications remain stable.
Area of Science:
- Cardiology
- Medical Devices
- Sudden Cardiac Death Prevention
Background:
- Implantable cardioverter-defibrillators (ICDs) are crucial for preventing sudden death in hypertrophic cardiomyopathy (HCM).
- Long-term performance and complication data for ICDs in HCM patients is limited, hindering optimal clinical practice.
Purpose of the Study:
- To evaluate the long-term performance and complication profile of primary prevention ICDs in hypertrophic cardiomyopathy patients.
- To provide insights into the temporal trends of ICD therapy and device-related issues over extended follow-up periods.
Main Methods:
- A cohort of 217 consecutive hypertrophic cardiomyopathy patients who received primary prevention ICDs before 2008 were followed for at least 10 years.
- Data on appropriate and inappropriate ICD interventions, device complications, and arrhythmic sudden death events were analyzed.
Main Results:
- 21% of patients experienced appropriate ICD interventions, with the majority occurring 5-10 years post-implant.
- Inappropriate shocks decreased over time, while major complications like infection and lead issues occurred in 12% without increasing frequency.
- No arrhythmic sudden death events were observed in the study cohort.
Conclusions:
- ICD therapy in HCM patients often follows a period of dormancy, with increasing frequency of interventions occurring years after implantation.
- Inappropriate shock rates decline over time, and major device complications do not escalate with extended follow-up.
- Long-term ICD use in HCM is associated with sustained protection against sudden death without a significant increase in device-related complications.
Background:
The implantable cardioverter-defibrillator (ICD) is effective for preventing sudden death in patients with hypertrophic cardiomyopathy. However, data on performance and complications of implanted ICDs over particularly long time periods to inform clinical practice is presently incomplete.
Methods:
The study cohort comprises 217 consecutive hypertrophic cardiomyopathy patients with primary prevention ICDs implanted before 2008 and followed for ≥10 years (mean 12±4; range to 31).
Results:
Patients were 38±17 years at implant and 45 (21%) experienced appropriate interventions terminating ventricular tachycardia/ventricular fibrillation. The majority of ICD discharges occurred ≥5 years after implant (29 patients; 64%), including ≥10 years in 16 patients (36%). Initial device therapy increased in frequency from 2.3% of patients at <1 year to 8.5% of patients at ≥10-years after implant (P=0.005). Inappropriate ICD shocks in 39 patients occurred most commonly <5 years after implant (54%) and decreased in frequency with increasing time from implant (from 9.7% of patients at <5 years to 3.8% at ≥10 years, P=0.02). Other major device complications including infection and lead fractures and dislodgement occurred in 27 patients (12%) but did not increase in frequency over follow-up after implant (P=0.47). There were no arrhythmic sudden death events among the 217 patients with ICD.
Conclusions:
In hypertrophic cardiomyopathy, after a primary prevention implant, ICD therapy often followed prolonged periods of device dormancy and increased progressively in frequency over time, including one-third of patients with initial therapy after 5 to 9 years, and an additional one-third of patients at ≥10 years. Frequency of inappropriate shocks decreased over follow-up, likely reflecting standard changes in device programming, while occurrence of device complications, such as lead fractures/infection, did not increase during follow-up.
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