Implantable Cardioverter-Defibrillator Therapy in Apical Hypertrophic Cardiomyopathy: Insights From a Multicenter Study.

BACKGROUND AND

OBJECTIVES

Prognosis and risk markers of sudden cardiac death (SCD) remain incompletely defined in patients with apical hypertrophic cardiomyopathy (HCM). This study evaluated established SCD risk markers and compared long-term implantable cardioverter-defibrillator (ICD) therapy outcomes between apical and non-apical HCM.

METHODS

We analyzed 96 patients with HCM who underwent ICD implantation at 3 tertiary care hospitals in Korea. All SCD risk markers recommended by the 2024 American Heart Association (AHA)/American College of Cardiology (ACC) and 2023 European Society of Cardiology (ESC) guidelines were assessed in apical HCM patients who experienced aborted cardiac arrest (ACA) and/or documented ventricular fibrillation (VF). The long-term outcomes of ICD therapies between apical and non-apical HCM patients were evaluated.

RESULTS

Of the 15 patients (15.6%) with apical HCM, 7 (46.7%) experienced ACA and/or documented VF. All 7 patients had at least one SCD risk marker as defined by the 2024 AHA/ACC or 2023 ESC guidelines. The most common markers were late gadolinium enhancement, unexplained syncope, non-sustained ventricular tachycardia, and left atrial enlargement. No significant differences were observed in total (33.3% [5/15] vs. 30.9% [25/81], p=1.00) or appropriate (13.3% [2/15] vs. 19.8% [16/81], p=0.73) ICD therapy events between patients with apical and non-apical HCM over a mean follow-up of 6.03±4.75 years.

CONCLUSIONS

Patients with apical HCM who received ICDs for secondary prevention exhibited substantial risk markers at the index event and remained at risk for recurrent ventricular arrhythmias. These findings support risk-guided ICD implantation and careful long-term follow-up in patients with high-risk apical HCM.