Introduction. Strategies for reliable selection of high-risk hypertrophic cardiomyopathy (HCM) patients for prevention of sudden cardiac death (SCD) with implantable cardioverter-defibrillators (ICDs) are still debated. We therefore assessed the performance of SCD risk strategies (2014 ESC SCD 5-year risk score and 2020 AHA/ACC risk factor strategy) in predicting lethal arrhythmic events (LAE) among a cohort of HCM patients.
Methods. Sixty-five patients (42  17 years) with a diagnosis of HCM were enrolled from 1990 to 2021. Patients were managed according to the best available treatment strategy for HCM in the different clinical eras.
Results. Of the 65 patients, 28 (43 %) received an ICD (23 in primary, 5 in secondary prevention). During 15 years (15 [6.21], range 1-33 years, 1014 patients/year), a total of 10 LAE were observed (0.98%/year). According to ESC SCD risk score and AHA/ACC risk-factors patients were respectively categorized as: 7 (10 %) and 35 (54 %) at high-risk, 14 (22 %) and 24 (37 %) at intermediate to high- risk, 44 (68%) and 6 (9%) at low-risk. Four (2.8 %) patients experiencing LAE were misclassified as low- risk by the ESC SCD Risk score, whereas none by the AHA/ACC model. Of the 7 patients categorized as high-risk by the ESC SCD Risk Score, 2 (29 %) experienced a LAE, whereas of the 35 patients at high-risk by the AHA/ACC, 9 (26 %) suffered a LAE. No difference in the AUC was shown between the two models (0.72; 95 % CI 0.60–0.83, 0.66; 95 % CI 0.49–0.84, p = 0.55).
Conclusions. In this single-center HCM cohort, incidence of LAE was low (0.98 % /year). Although 2020 AHA/ACC stratification did not show a higher association with arrhythmia than ESC 2014 SCD risk score, it had a much higher sensitivity and would result in a IIa or IIb indication for an ICD implantation in up to 91 % of our HCM patients.