Utility of stimulation in ICD carriers with HCM: Insights from the Heidelberg HCM Registry

Introduction:

The need for long-term stimulation in HCM patients with ICD indications is currently under discussion in the literature. In the era of subcutaneous defibrillators demonstrating non-inferiority to transvenous systems and potentially fewer lead-related complications, it is imperative to identify patients who need long-term stimulation.

This study retrospectively analysed ICD carriers of the Heidelberg HCM registry in relation to development of a stimulation indication over long-term follow-up.

Methods

Retrospective analysis of ICD carriers with HCM. Stimulation indication was defined as follows: 1. Development of symptomatic bradycardia and accordingly, an increase of ventricular pacing > 20%. 2. CRT upgrade. 3. Termination of VT (ventricular tachycardia) with ATP (antitachycardia pacing).

Results

In the registry 82 patients were identified. Of these, 19 were lost to follow-up. Of the remaining patients, 12 had a pacing indication at the time of implantation. Over a median follow-up period of 93.3 months, 7 patients developed bradycardia and an additional 2 patients had a successful termination of VT with ATP (out of 8 VT episodes in total). Kaplan-Meier estimate analysis showed a median survival time without pacing indication of 180 months (Figure 1). The incidence rate of stimulation indication was 1.48 per 100 person-years.

Discussion

In a long-term follow-up ICD registry of patients with HCM, a small portion developed a stimulation indication or experienced successful ATP. Studies are needed to identify patients at higher risk for developing a pacing indication, in order to tailor device choices for this patient population.