Prognostic value of midwall late gadolinium enhancement (LGE) on cardiac MRI in heart failure patients with non-ischaemic dilated cardiomyopathy (DCM) post primary prevention complex device therapy

Abstract Background/ Introduction Current ESC guidelines suggest that primary prevention complex device implantation should be considered in patients with DCM and a left ejection fraction (LVEF) ≤ 35% despite optimal medical therapy. However, randomised controlled trials such as the DANISH study have not demonstrated a reduction in total mortality in patients with DCM post ICD implantation. Therefore, there is unmet need for enhanced risk stratification prior to complex device implantation in this cohort of heart failure patients. Although, midwall LGE is an overall adverse prognostic marker in patients with heart failure, it’s specific prognostic value in the DCM population post complex device therapy has not been fully explored. Purpose We investigated the prognostic value of midwall LGE in a specific cohort of DCM patients who underwent primary complex device therapy. We hypothesise that patients with midwall LGE prior to complex device implantation will experience more adverse cardiovascular outcomes after complex device therapy compared to patients without midwall LGE. Methods All patients with DCM and undergoing primary complex device therapy were identified between 2017 and 2024. Only patients who underwent Cardiac MRI prior to complex device implantation were included in our study. Cardiac MRI reports were analysed and reviewed for the presence of midwall scar. Our primary endpoint was a composite of appropriate device therapies (Shock/ATP), heart failure admissions, all-cause mortality and heart transplant/LVAD. Results 68 patients with DCM underwent Cardiac MRI prior to complex device therapy. 41 patients (60.3%) patients had LGE (midwall, RV insertion and sub-epicardial) compared to 27 (39.7%) with no LGE. 31 patients (75%) had midwall LGE and the primary end point occurred in 16 of 22 (51.6%) of these patients compared to 6 of 22 (22.2%) patients with no LGE (p = 0.022) [Table 1]. Kaplan-Meier analysis showed a significantly higher likelihood of the primary outcome in patients with midwall LGE compared to those without [Figure 1]. This higher proportion of primary outcome events was mainly driven by heart failure admissions with 13 of 17 (41.9%) patients in the midwall LGE group compared to 4 of 17 (14.8%) in patients without (p = 0.025). There was a higher incidence of appropriate device therapy (shock/ATP) and all-cause mortality in patients with midwall LGE (25.8% and 22.6%, respectively) compared to patients without LGE (11.1% and 14.8%, respectively) p-values 0.16 and 0.46 respectively. Conclusion Patients with DCM and midwall LGE experience a significantly higher proportion of adverse cardiovascular outcomes post complex device implantation compared to patients without midwall LGE. Our study highlights the key importance of midwall LGE in enhancing the risk stratification of DCM patients undergoing primary complex device implantation.