Rowin EJ, Maron MS, Adler A, et al. - According to findings, recognition and inclusion of novel guideline-supported cardiac magnetic resonance (CMR)-based risk markers improves selection of hypertrophic cardiomyopathy (HCM) patients for sudden death (SD) prevention with ICDs. Absence of CMR-based markers from the ESC risk score partly accounts for it not detecting many HCM cases with SD events. Observations support incorporation of CMR as a routine component of HCM patient assessment and risk stratification.

• In this longitudinal study of 1149 HCM patients who underwent primary prevention ICD implants, the specific impact of newer predominantly CMR-based risk markers (LV apical aneurysm, extensive late gadolinium enhancement and end-stage with systolic dysfunction) was evaluated.

• In 14% of patients, device therapy terminating VT/VF 4.6 ± 4.2 years post-implant was revealed.

• CMR-based markers alone or in combination resulted in ICD implantation in 49 of the 162 patients (30%) experiencing device-therapy.

• Especially low ESC scores (<4%/5-years) would have excluded an ESC-ICD recommendation for 67 cases that still experienced appropriate ICD therapy including 26 with the CMR-based risk markers not a component of the ESC formula.