Heart failure & cardiomyopathiesCohort study

International Experience With Implantable Cardioverter Defibrillators for the Prevention of Sudden Death in High-Risk Patients With Hypertrophic Cardiomyopathy

CirculationPublished

  • Retrospective cohort study
  • multicentre
  • international
  • 25 hypertrophic cardiomyopathy (HCM) centres
  • consecutive patients

Authors' conclusion

In this international multicenter study, the largest to date, including >3300 consecutive patients with HCM and ICDs, device therapy terminated potentially lethal ventricular tachyarrhythmias in 1 of 6 patients, with low HCM-related mortality rates for patients with ICDs.

Study context

Population
Consecutive patients with hypertrophic cardiomyopathy with implanted cardioverter-defibrillators (ICDs) (1992 to 2024), 25 centres worldwide63% men
Participants
3,387 patients
Exposure
Secondary prevention vs Primary prevention
  • Secondary preventionn = 247
  • Primary preventionn = 3,140
Outcome
Appropriate ICD therapy for life-threatening ventricular arrhythmias
Follow-up
7±6 years (up to 32 years)

Main finding

As reported in the abstract

≥1 appropriate ICD therapy · 7±6 years
GroupValueAnnual rate
Secondary prevention35%6.4%/y
Primary prevention15%2.2%/y
Overall ≥1 appropriate ICD therapy: 550 patients (2.6%/y)
16%

Observational data: associations, not effects.

Further findings

Mortality, primary prevention
6% · 194 of 3140

Primary prevention: timing of appropriate therapy

Median time to first appropriate therapy after implantation
4 years
First appropriate therapy ≥10 years after implantation
16%
Multiple interventions
47%

Independent predictors of appropriate ICD therapy

Unexplained syncope, LV apical aneurysms, LV systolic dysfunction, nonsustained VT on ambulatory monitoring

Survival free from HCM-related mortality · 10 and 20 years

10 years
97%
20 years
91%

Safety

Device failures in those with life-threatening ventricular tachyarrhythmias

Device failures
2.4%

Original publication

International Experience With Implantable Cardioverter Defibrillators for the Prevention of Sudden Death in High-Risk Patients With Hypertrophic Cardiomyopathy. Circulation. Published 25 August 2026. doi:10.1161/circulationaha.125.078597

Summarised from the published abstract; every number is checked against it