Non-dilated left ventricular cardiomyopathy (NDLVC), a newly defined cardiomyopathy subtype characterized by non-ischemic myocardial abnormalities without left ventricular dilation, poses challenges in prognosis assessment and risk stratification. This is a retrospective observational study aiming to explore the prognostic value of cardiac magnetic resonance (CMR) findings and identify key risk factors for adverse cardiovascular outcomes in patients with NDLVC.

We will retrospectively enroll patients diagnosed with NDLVC who underwent CMR examination at the study institution during the predefined study period. CMR parameters, including left ventricular ejection fraction (LVEF), late gadolinium enhancement (LGE) patterns, myocardial strain, and the extent of myocardial fibrosis or fatty replacement, will be extracted and analyzed. The primary endpoint is a composite of major adverse cardiovascular events (MACE), including all-cause mortality, heart transplantation, or left ventricular assist device (LVAD) implantation.

The study intends to clarify the association between specific CMR features and long-term prognosis in NDLVC patients, thereby establishing a CMR-based risk stratification strategy to guide clinical decision-making and improve patient outcomes. Given the retrospective nature, data will be collected from electronic medical records and CMR databases, with ethical approval obtained prior to study initiation.

Inclusion Criteria:

• age ≥ 16 years;
• indexed left ventricular end-diastolic volume (LVEDVi) <96 mL/m2 in females and <105 mL/m2 in males at baseline cardiac magnetic resonance (CMR);
• either left ventricular ejection fraction (LVEF) <50% and/or non-ischemic left ventricular (LV) scar/fatty replacement at baseline cardiac magnetic resonance.

Exclusion Criteria:

• lacked enhanced CMR images due to contraindications for receiving gadolinium contrast, such as severe renal disease;
• ischemic heart disease, defined as stenosis of >50% in a major epicardial coronary artery underwent coronary computed tomography angiography or coronary angiography, ischemic late gadolinium enhancement (LGE) pattern on CMR indicating prior infarction, or prior coronary revascularization;
• abnormal loading conditions, defined as moderate to severe valvular heart diseases, congenital heart diseases, uncontrolled hypertension;
• systemic rheumatologic diseases or sarcoidosis;
• diagnostic criteria for other cardiomyopathies according to the European Society of Cardiology (ESC) definitions.

Non-dilated left ventricular cardiomyopathy (NDLVC), formally recognized in the 2023 ESC guidelines as a distinct entity,1 encapsulates patients with non-ischemic fibrosis or fatty replacement or isolated systolic dysfunction without ventricular dilatation.