*2.1. Study Population*

We conducted a prospective study on 302 consecutive patients with first NIDCM diagnosis, which were examined in the 2th Department of Internal Medicine of the Iuliu Hatieganu University of Medicine and Pharmacy from October 2017 to November 2019. The inclusion criteria were [1]: (1) impaired global LV function with a LV ejection fraction (LVEF) ≤45%; (2) LV chamber dilation with an indexed LV end-diastolic volume (LVEDV) <sup>≥</sup>97 mL/m2; both cMRI-determined. The exclusion criteria are represented by (1) IHD, other cardiomyophaties, significant valvular and congenital heart disease (CHD, CVD); (2) contraindications to cMRI (incompatible metallic devices, significant chronic renal disease with estimated glomerular filtration rate <30 mL/min/1.73 m2, or claustrophobia); (3) refusal to participate in the study (Figure 1). IHD was excluded by coronarography in 72 patients (41%), stress imaging studies in 64 patients (36%) and the remaining 42 patients (23%) had no history of angina, 1 or 0 risk factors for IHD and stress ECG test and computed tomography coronary angiography with Agatston calcium scoring were also negative.

We recorded demographic data including age, gender, height, weight, medical history, cardiovascular symptoms (dyspnoea, syncope, palpitations), and current medication; biomarkers and 12-lead ECG. 24-h Holter monitoring, transthoracic echocardiography and cMRI were performed. The current research was approved by the Ethics Committee of the Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca—decision number 280/26.07.2018. The study was conducted in accordance with the principles of the Declaration of Helsinki. All patients were informed about the investigation protocol and signed a written consent form.

**Figure 1.** Flow chart detailing the identification of the study cohort. Abbreviations: cMRI, cardiac magnetic resonance imaging; LGE, late gadolinium enhancement; LVEDV, left ventricular end diastolic volume; LVEF, left ventricular ejection fraction.
