**1. Introduction**

Nonischemic dilated cardiomyopathy (NIDCM) is the most common primary myocardial disease, being characterized by left ventricular (LV) enlargement and global systolic LV function impairment in the absence of ischemic heart disease (IHD), hypertension or valve disease [1]. Due to its significant

increased mortality [2] and sudden cardiac death (SCD) risk [3], NIDCM represents an important global healthcare burden. Nowadays, the development of more effective methods of assessing NIDCM severity and the risk of major adverse cardiovascular events (MACEs) remains a topic of great interest for current research.

While current guidelines recommend echocardiography as the first line of investigation in patients with NIDCM [4,5], it cannot evaluate the structural myocardial impairment [6]. Myocardial replacement fibrosis is part of the cardiac remodelling process, being responsible for heart failure (HF), ventricular arrhythmia (VA) and SCD. It is encountered in one-third of NIDCM patients, being detected using cardiac magnetic resonance imaging (cMRI) with late gadolinium enhancement (LGE) [7–10]. T1 mapping imaging is a state-of-the-art cMRI technique that is able to characterize extracellular volume fraction and it has been validated by comparative studies with the histopathological examination in NIDCM [11,12]. LV long-axis strain (LAS) determined by cMRI is an efficient and reliable method for quantifying global LV longitudinal function and it has an important prognostic value in patients with NIDCM [13,14]. Last but not least, cMRI-determined LV sphericity index (LVSI) is a parameter that predicts MACEs in NIDCM and it can be used in the assessment of LGE presence and LGE mass [15,16].

The aim of this study was to investigate the relationship between cardiac remodelling process and MACEs, and if it increases outcome prediction beyond LGE, in patients with NIDCM.
