*2.2. cMRI*

All cMRI images were ECG-gated and were acquired during apnoea with a 1.5 T magnetic resonance (MR) scanner (Magnetom Symphony, Siemens Medical Solutions, Erlanger, Germany). A standard scanning protocol that was in accordance with current international guidelines was used [17]. The acquisition of fast imaging employing steady-state free precession (SSFP) sequences was performed to detect ventricular function and mass in the conventional cardiac short-axis and long-axis planes (including two-chamber, three-chamber, and four-chamber), to enclose both ventricles from base to apex. SSFP sequence parameters were as follows: repetition time (TR) 3.6 ms; echo time (TE) 1.8 ms; flip angle 60◦; slice thickness 6 mm; field of view 360 mm; image matrix of 192 × 192 pixels; voxel size 1.9 × 1.9 × 6 mm; 25–40 ms temporal resolution reconstructed to 25 cardiac phases. LGE imaging was performed to detect focal myocardial scars acquired 10 min after intravenous administration of 0.2 mmol/kg gadoxetic acid (Clariscan, GH Healthcare AS, Oslo, Norway) in long- and short axis-views, using a segmented inversion-recovery gradient-echo sequence. LGE imaging sequence parameters were presented by: TR 4.8 ms, TE 1.3 ms, and inversion time 200 to 300 ms. Inversion time was adjusted to optimize nulling of apparently normal myocardium. Brachial blood pressure was monitored during cMRI-SSFP acquisitions.

Image analysis: All images were evaluated by two experienced observers, blinded to all clinical data. LVEDV and LV end-systolic volume (LVESV), LVEF and end-diastolic LV mass (LVM) were measured on short-axis cine-SSFP images. Epicardial and endocardial borders were traced semi-automatically at end-diastole and end-systole using specialized software (Syngo.Via VB20A\_HF04, Argus, Siemens Medical Solutions). The maximum left atrium (LA) and right atrium (RA) volumes were measured in all patients from the four-chamber view. All volumes were indexed to body surface area. Tricuspid annular plane systolic excursion (TAPSE) was measured from the mid-four-chamber cardiac view to assess right ventricular (RV) longitudinal motion. LV longitudinal function was assessed by LAS, defined as the difference in mitral annular displacement at end-systole vs. end-diastole, and expressed as a percentage [13]. LVSI was calculated by dividing LVEDV to the volume of a sphere whose LV length (L) is measured at end-diastole: LVSI <sup>=</sup> LVEDV/(π/<sup>6</sup> <sup>×</sup> (L)3) [15] (Figure 2).

The presence and distribution of LGE in the LV were assessed from short-axis images, using the 17-segments model, as recommended by the American Heart Association [18], and were quantified using a signal intensity threshold of >5SD above a remote reference for normal myocardium. Due to the fact that the LGE quantification with the threshold of 5SD demonstrated the best agreement with visual assessment and best reproducibility among different technique thresholds, we used a threshold of 5SD above the signal intensity of normal myocardium [19,20]. LGE's distribution was characterized as mid-wall, subepicardial, focal or diffuse. The assessment of LGE mass in the LV was automatically quantified from short-axis LGE images using cardiac dedicated software (cvi42, Circle Cardiovascular Imaging Inc., Calgary, CA). The extent of LGE was expressed by gram (g) and also as percentage of LVM. According to the cMRI, the studied population was divided into two groups, namely: patients without LGE (LGE−) and patients with LGE (LGE+).
