CarDiac magnEtic Resonance for prophylactic Implantable-cardioVerter defibrillAtor ThErapy in Non-Dilated Left Ventricular Cardiomyopathy: a sub-study from the DERIVATE Registry

Aims Accurate risk stratification for patients with non-dilated left ventricular cardiomyopathy (NDLVC) remains challenging due to lack of dedicated clinical trials. This post hoc analysis aims to delineate the arrhythmic risk and assess the incremental value of cardiac magnetic resonance (CMR) imaging in the CarDiac magnEtic Resonance for prophylactic Implantable-cardioVerter defibrillAtor ThErapy (DERIVATE) study cohort meeting the NDLVC diagnostic criteria. Methods and results Patients with NDLVC from the DERIVATE registry were identified in the absence of left ventricular (LV) dilatation and in the presence of non-ischaemic LV scarring ('fibrotic NDLVC') or isolated LV systolic dysfunction (LV ejection fraction < 50%) without fibrosis ('hypokinetic NDLVC'). The primary endpoint was all-cause mortality. Major adverse arrhythmic cardiac events (MAACE) were the secondary endpoint and included sudden cardiac death (SCD) and aborted SCD. One hundred and ninety-seven NDLVC patients were identified from the cohort of the DERIVATE study (mean age: 59 ± 14 years; male: 135). Over a median follow-up of 2.7 years, 15 (8%) patients died and 8 (4%) experienced MAACE. Patients with 'hypokinetic' NDLVC had significantly lower rates of MAACE than non-ischaemic dilated cardiomyopathy (NIDCM) (P = 0.001), while patients with 'fibrotic' NDLVC had same rate of both primary (P = 0.48) and secondary endpoints (P = 0.616) compared with NIDCM patients. Multivariable analysis identified late gadolinium enhancement (LGE) with midwall distribution as an independent predictor of MAACE in NDLVC patients (hazard ratio 6.7, 95% confidence interval: 1.33-33.67; P = 0.021). Conclusion NDLVC patients exhibit a heterogeneous risk profile for arrhythmic events. The presence of midwall LGE, similarly to NIDCM, is a significant predictor of MAACE, highlighting the importance of CMR imaging for risk stratification.