Abstract: Objective To quantitatively assess cardiac functions in patients with cardiac amyloidosis (CA) and hypertrophic cardiomyopathy (HCM) using cardiac magnetic resonance-feature tracking (CMR-FT) technique and evaluate the prognostic value of CMR-FT in patients with CA. Methods We retrospectively collected the data from 31 CA patients with systemic amyloidosis confirmed by Congo red staining and serum immunohistochemistry after extracardiac tissue biopsy undergoing CMR at our hospital from March, 2013 to June, 2021. Thirty-one age and gender matched patients with asymmetric left ventricular wall hypertrophy and 31 healthy individuals without organic or functional heart disease served as the controls. Radial, circumferential and longitudinal strains and strain rates of the left ventricle at the global level and in each myocardial segment (basal, middle and apical) were obtained with CMR-FT technique and compared among the 3 groups. The predictive value of myocardial strains and strain rates for all-cause mortality in CA patients was analyzed using a stepwise COX regression model. Results The left ventricular volume, myocardial mass, ejection fraction and cardiac output differed significantly among the groups (P<0.05). Except for apical longitudinal strain, the global and segmental strains were all significantly lower in CA group than in HCM group (P<0.05). The global and segmental strains were all significantly lower in CA group than in the healthy individuals (P<0.05). The basal strain rates in the 3 directions were significantly lower in CA group than in the healthy individuals (P<0.05), but the difference in apical strain rates was not statistically significant between the two groups. Multivariate stepwise COX analysis showed that troponin T (HR=1.05, 95% CI: 1.01-1.10, P=0.017) and middle peak diastolic circumferential strain rate (HR=6.87, 95% CI: 1.52-31.06, P=0.012) were strong predictors of death in CA patients. Conclusion Strain and strain rate parameters derived from CMR-FT based on cine sequences are new noninvasive imaging markers for assessing cardiac impairment in CA and cardiac function changes in HCM, and provide independent predictive information for all-cause mortality in CA patients.

Key words: cardiac amyloidosis; cardiac magnetic resonance-feature tracking; left ventricle; myocardial strain; myocardial strain rate