## 4 Discussion
### Role of CMR-FT in the Perioperative Assessment of Right Ventricular Function  
It has been of clinical interest to assess the precise impact of Cone repair on RV function; however, identifying a parameter that reflects myocardial changes remains challenging. Several studies have evaluated conventional parameters of RV function before and after Cone repair using echocardiography and CMR, many of them reporting decreased postoperative RVEF and RVSVi [4; 5; 7; 8], consistent with our findings. However, it is crucial to recognize that the loading conditions strongly influence these parameters of RV function, and the regurgitant volume of the insufficient tricuspid valve may contribute to a 'false' impression of normal RVEF and RVSVi before surgery. With TV repair, the regurgitant volume is retained in the ventricle and the postoperative RVEF and RVSVi reflect only the volume ejected forward through the pulmonary valve. Hence, in the postoperative assessment, the impaired RVEF and RVSVi do not solely indicate postoperative RV deterioration; rather, they reveal a pre-existing myocardial dysfunction that becomes more apparent with a competent TV. Additionally, they reflect the differing volume status of the RV before and after Cone repair, making these parameters unsuitable overall for perioperative assessment of myocardial function [8]. Parameters used by other authors to evaluate the actual perioperative change in RV function were pulmonary artery flow and left ventricular end-diastolic volumes, reflecting the ability of the RV to pump the blood forward [4; 5; 8]. Figure 3: Four-chamber view of the same patient before (**a**) and after (**b**) Cone repair. (**a**) pre Cone (14 years old, male, RVEDVi 188 mL/m\({}^{2}\)); (**b**) 12-month post Cone (RVEDVi 249 mL/m\({}^{2}\)). Hinge points of the tricuspid valve before and after Cone repair (white arrows); course of the tricuspid valve (dotted lines). RV strain has been proven to be valuable in detecting myocardial dysfunction in several cardiac diseases, even when functional parameters such as RVEF remained within the normal range [12; 13]. In the current study, we noted a deterioration of GLS alongside improvements in GRS and GCS following Cone repair (Figure 2). These findings align with a recent echocardiographic study by [PERSON] et al., encompassing 257 EA patients. Their study reported similar results, wherein post Cone repair, the RV fractional area change (FAC), as an indicator of longitudinal RV function, demonstrated a significant decline. At the same time, there was a slight enhancement in the RV short-axis FAC [17]. The deterioration of GLS, similar to RVEF and RVSVi, observed in this study, suggests that GLS might also be affected by the preoperatively reduced afterload, thus masking the actual preoperative myocardial function, since pushing the blood volume backward through the TV is easy for the RV in the preoperative state. postoperatively sustained pulmonary artery flows and left ventricular volumes reflect the maintained effective function of the RV, suggesting that postoperative impairment of these parameters is due to increased postoperative afterload rather than true myocardial impairment after Cone repair. Our previous study showed that in unoperated EA patients, GLS did not differ from that of healthy individuals whereas significant impairment was observed in GCS and GRS, suggesting that in EA there is a predominant impairment of short-axis contraction, while the longitudinal function remains preserved [10]. Contrarily, a recent CMR study conducted by [PERSON] et al. demonstrated that in unoperated patients with TR unrelated to EA, specific individuals exhibited a reduction in RV GLS while maintaining preserved RVEF. In these cases, the values of compensatory GRS and GCS were above normal levels [18]. This observation may support the hypothesis that in EA, longitudinal and circumferential fibers contribute differently to RV systolic function than normal hearts.