Prevalence and prognosis of non-dilated left ventricular cardiomyopathy in patients referred for cardiac magnetic resonance

Background: The European Society of Cardiology recently identified non-dilated left ventricular cardiomyopathy (NDLVC) as a distinct clinical entity. This study aimed to determine the prevalence and prognosis of NDLVC in a specific cohort. Materials and methods: This retrospective cohort analysis included patients referred for routine cardiac magnetic resonance (CMR) and who underwent stress myocardial perfusion or viability assessment from September 2017 to July 2020. Patients with coronary artery disease (CAD) from history or CMR imaging were excluded. Participants were categorized into dilated cardiomyopathy (DCM), NDLVC, and control groups. NDLVC was defined as the presence of non-ischemic LGE or isolated global left ventricular hypokinesia without left ventricular dilatation. The primary endpoints were all-cause mortality or heart failure events. Results: Among 4377 CMR patients, 2278 patients remain after the exclusion. Mean age was 66.3 ± 13.2 years, and 60.4% were females. Upon categorization, there were 1996 controls (87.6%), 172 DCM patients (7.6%), and 110 NDLVC patients (4.8%). Among the NDLVC patients, 64 patients (58.2%) had non-ischemic LGE, which included mid-wall, subepicardial, patchy and right ventricular insertion types. Over a median follow-up of 37.5 months, DCM patients exhibited higher rates of composite outcomes than NDLVC and control patients. Likewise, NDLVC patients also had significantly greater rates of composite outcomes and heart failure events than the controls. Conclusion: NDLVC had a prevalence of 2.5% among routine stress or viability CMR cases and had a significantly higher rate of clinical outcomes than the controls but lower than DCM patients. These findings underscore the distinct clinical significance of NDLVC. Key Points: Question What is the prevalence and clinical prognosis of non-dilated left ventricular cardiomyopathy (NDLVC) in patients undergoing routine stress or viability cardiac MRI? Findings NDLVC was present in 2.5% of patients undergoing routine stress or viability cardiac MRI and was associated with worse clinical outcomes than controls, but more favorable than dilated cardiomyopathy. Clinical relevance Identifying NDLVC on routine cardiac magnetic resonance (CMR) provides prognostic value, helping to recognize patients at increased risk of heart failure events despite preserved left ventricular size.