Abstract 4368062: Subendocardium-involved Late Gadolinium Enhancement Pattern with Noncoronary Distribution Predicts Sudden Cardiac Death in Nonischemic Dilated Cardiomyopathy

Background: Beyond the predominant nonischemic late gadolinium enhancement (LGE) pattern, an subendocardium-involved LGE patternwas also identified in a subset of patients with nonischemic dilated cardiomyopathy (DCM). However, the distribution and predictive value of subendocardium-involved LGE pattern with noncoronary distribution in nonischemic DCM are still unknown. Research Questions To investigate the prevalence, distribution, and prognostic value of subendocardium-involved LGE pattern for sudden cardiac death (SCD) in nonischemic DCM. Methods: In this single-center retrospective study, 890 consecutive nonischemic DCM patients who underwent cardiac magnetic resonance (CMR) with LGE imaging were included. Subendocardium-involved LGE pattern in nonischemic DCM was characterized by subendocardial or transmural LGE with noncoronary distribution. Patients with significant coronary disease that would lead to subendocardium-involved LGE were excluded. The combined endpoints included SCD and major ventricular arrhythmias (SCD/MVA). Results: Among 890 patients (mean age 45.7 years, 78.7% men), 14.3% patients had subendocardium-involved LGE pattern, most commonly in the lateral wall (9.3%). Over a median follow-up of 77 months (Q1-Q3: 40-92 months), the study outcome occurred in 50 (5.6%) patients. In comparison to patients without SCD/MVA, patients with SCD/MVA had lower left ventricular ejection fraction (LVEF) (20.6% vs 24.1%; P = 0.002), higher left ventricular end-diastolic volume index (LVEDVI) (180.1 vs 154.3; P = 0.004), and a higher prevalence of LGE (76.5% vs 34%; P < 0.001) and subendocardium-involved LGE pattern (29.4% vs 13.4%; P = 0.002). In addition, the presence of subendocardium-involved LGE pattern in the lateral wall was significantly higher in patients with SCD/MVA (25.5% vs 8.3%; P < 0.001). In Cox multivariable analysis, lateral subendocardium-involved LGE pattern was independently associated with a higher risk of SCD/MVA compared with both absent LGE (adjusted hazard ratio [HR] 14.08; 95% confidence interval [CI] 6.1-32.26; P < 0.001) and LGE without this specific imaging biomarker (HR 2.5; 95% CI 1.26-4.98; P = 0.009). Conclusion: In patients with nonischemic DCM, subendocardium-involved LGE pattern with noncoronary distribution was observed in 1 of every 7 patients, with the lateral wall being the most prevalent location. Lateral subendocardium-involved LGE pattern was independently associated with higher risk of SCD/MVA in nonischemic DCM.