Evaluation of left ventricular systolic function using inward displacement by cardiac magnetic resonance in patients with myocardial necrosis (RF_TH_223)

Inward displacement (InD) is a recently described cardiac magnetic resonance (CMR) technique that quantitatively measures the endocardial displacement of the left ventricle (LV) towards its center, as compared to the traditional visual assesment of regional function. There is limited evidence of InD's utility in patients with myocardial necrosis and its correlation with other parameters such as global longitudinal strain (GLS) and LV ejection fraction (LVEF). We compared parameters of myocardial systolic function in patients with myocardial necrosis defined as late gadolinium enchancement of at least 1 myocardial segment in  ≥50% of the myocardial wall thickness, to those of a healthy control group.

Methods:

We analyzed the LV InD using a commercially available software (Medis Medical Imaging Systems BV, Leiden, Netherlands). Regional InD measured by CMR of a predominantly affected vascular territory of patients with myocardial necrosis was quantified and compared with a the control group. A vascular territory was assigned according to the 17-segment myocardial model and a correlation was made between the global and segmental average InD, LVEF and GLS.

Results:

We analyzed 1411 segments in 83 patients with myocardial necrosis and 510 segments in 30 healthy subcjects. Of the 83 patients, distribution of the main vascular territories affected was: 58 patients (69.9%) for the anterior descending artery (LAD), 7 (8.4%) for the circumflex artery (LCx) and 18 (21.7%) for the right coronary artery (RCA). The global InD of the patients with myocardial necrosis was lower as compared to control group (22.2% vs 28.5% respectively p < 0.02), when segmentally analyzed by vascular territory,  we found significant differences in the 3 vascular territories (LAD, LCx and RCA) (P< 0.03, P< 0.007, P< 0.007 respectively) as compared to controls. A correlation between InD, LVEF and GLS was found, however, a higher correlation was observed between InD and LVEF as compared to GLS (R²= 0.92 vs 0.78, respectively).

Conclusion:

Our study shows that it is feasible to use InD as a quantitative measure of myocardial involvement that reflects regional cardiac function and its correlation with known prognostic parameters of global and segmental function in patients with myocardial necrosis. Overall, a significant difference was established in healthy subjects versus patients with myocardial necrosis, InD was able to discriminate normal as well as abnormal segments in a quantitative fashion, as well as a close correlation between InD, LVEF and SLG, further studies are warranted.