Redefining the Risk of Major Arrhythmic Events in Non-Ischemic Cardiomyopathy: Insights from the DERIVATE-NICM Study

Aims Selection of the patients for implantable cardioverter defibrillator primary prevention therapy in non-ischaemic cardiomyopathy (NICM) needs to be improved. To evaluate the additional prognostic value of a new cardiac magnetic resonance (CMR) score based on late gadolinium enhancement (LGE) pattern distribution (DERIVATE Risk Score 2.0) when compared with previously published DERIVATE Risk Score 1.0, which is based solely on quantitative parameters, in a cohort of NICM patients enrolled in the DERIVATE registry. Methods and results One thousand three hundred and eighty-four NICM patients with chronic heart failure and left ventricular ejection fraction (LVEF) < 50% were evaluated for primary sudden cardiac death prevention therapy. Major adverse arrhythmic cardiac events (MAACEs) were the primary endpoint. During a median follow-up of 959 days, MAACE occurred in 128 (9.2%) patients. In the multivariate analyses, male gender [hazard ratio (HR): 1.605 (95% confidence interval, CI: 1.051-2.451); P = 0.028], LVEF per point % [HR: 0.977 (95% CI: 0.961-0.993); P = 0.005] and presence and location of midwall LGE [weighted HR: 1.066 (95% CI: 1.045-1.086), P < 0.001] were independent predictors of MAACE. A multi-parametric CMR-weighted predictive-derived score (DERIVATE Risk Score 2.0) provided a higher additional prognostic value vs. transthoracic echocardiography-LVEF cut-off of 35% when compared with the previous published DERIVATE Risk Score 1.0 with a net reclassification improvement of 54.52% (95% CI: 36.52-72.52%; P < 0.001). These findings were confirmed in the validation cohort. Conclusion The presence of midwall LGE, but also the location of scar, confers an added and independent MAACE risk to a large NICM population influencing the choice of treatment.