Time trends in ICD recommendations and predictors of device activation hypertrophic cardiomyopathy: a real-world
Miguel Marques Antunes1,2,3, Ricardo Carvalheiro1, Isabel Cardoso1
1Hospital de Santa Marta, Serviço de Cardiologia, Centro Clinico Académico de Lisboa (CCAL), Lisboa, Portugal.
Insights
Sudden cardiac death (SCD) risk in hypertrophic cardiomyopathy (HCM) is concerning. Evolving European Society of Cardiology (ESC) guidelines expand implantable cardioverter defibrillator (ICD) eligibility, yet some patients with events remain ineligible, necessitating refined risk prediction.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiovascular Imaging
Background:
- Sudden cardiac death (SCD) is a significant risk in hypertrophic cardiomyopathy (HCM).
- European Society of Cardiology (ESC) guidelines have evolved, broadening recommendations for implantable cardioverter defibrillators (ICDs) for primary prevention.
- Evaluating real-world clinical outcomes and event detection in HCM patients receiving ICDs is crucial.
Purpose of the Study:
- To assess clinical outcomes and event detection in a primary prevention hypertrophic cardiomyopathy (HCM) cohort receiving an implantable cardioverter defibrillator (ICD).
- To evaluate how evolving European Society of Cardiology (ESC) guidelines impact real-world ICD eligibility and event detection in HCM patients.
- To identify predictors of ICD activation in this patient population.
Main Methods:
- A single-centre retrospective study of 52 consecutive HCM patients who received an ICD for primary prevention (2014-2024).
- Collection of baseline clinical, imaging, and follow-up data.
- Classification of patients according to 2014, 2022, and 2023 ESC guidelines, with time-to-event analyses using univariate Cox regression.
Main Results:
- Over a median 2.2-year follow-up, 12% of patients experienced appropriate ICD therapy.
- The 2022/2023 ESC guidelines would have increased ICD eligibility by approximately 50% compared to the 2014 guideline.
- No guideline identified all patients with ventricular arrhythmias, and some with events remained ineligible for ICD implantation under any guideline; lower LVEF correlated with higher ICD activation risk.
Conclusions:
- Successive ESC guidelines have reduced the threshold for ICD implantation in HCM, increasing eligibility and procedures.
- Despite expanded eligibility, some patients with ventricular arrhythmias remain ineligible for ICDs, highlighting the need for improved risk prediction models.
- Individualized clinical judgment and complementary monitoring tools like implantable loop recorders (ILRs) are essential for managing HCM patients at risk of sudden cardiac death.
Background:
Sudden cardiac death (SCD) remains a major concern in hypertrophic cardiomyopathy (HCM). Over recent years, European Society of Cardiology (ESC) guidelines have broadened recommendations for implantable cardioverter defibrillator (ICD) implantation in primary prevention. We aimed to evaluate clinical outcomes and event detection in an HCM primary prevention cohort, while assessing how these evolving criteria translate into real-world ICD eligibility and event detection.
Methods:
We conducted a single-centre retrospective study including 52 consecutive HCM patients who received an ICD for primary prevention between 2014 and 2024. Baseline clinical, imaging, and follow-up data were collected. The primary endpoint was appropriate ICD therapy for ventricular tachycardia or fibrillation. Patients were classified according to the 2014, 2022, and 2023 ESC guidelines. Time-to-event analyses using univariate Cox regression were performed to identify predictors of ICD activation.
Results:
Over a median follow-up of 2.2 years, 6 patients (12%) experienced appropriate ICD therapy. According to ESC classifications, the 2022/2023 guidelines would have increased ICD eligibility by about 50% compared with the 2014 guideline, mainly due to the inclusion of extensive late gadolinium enhancement on CMR and reduced LVEF (<50%) as risk enhancers. However, no guideline set identified all patients who developed ventricular arrhythmias, and a subset of patients with events would not have been eligible for ICD implantation under any ESC recommendation. Lower LVEF was associated with higher risk of ICD activation.
Conclusions:
Successive ESC guidelines have lowered the threshold for ICD implantation in HCM, increasing eligibility but also implantations in event-free patients. Persistent event occurrence in ineligible individuals highlights the need for refined prediction models and individualized clinical judgment, including complementary tools such as ILR monitoring.
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