Relationship of Microvascular Obstruction with Global and Regional Myocardial Function Determined by Cardiac Magnetic Resonance after ST-Segment Elevation Myocardial Infarction / 中国医学科学杂志(英文版)

Objective To investigate the impact of microvascular obstruction (MVO) on the global and regional myocardial function by cardiac magnetic resonance feature-tracking (CMR-FT) in ST-segment-elevation myocardial infarction (STEMI) patients after percutaneous coronary intervention.Methods Consecutive acute STEMI patients who underwent cardiac magnetic resonance imaging 1 - 7 days after successful reperfusion by percutaneous coronary intervention treatment were included in this retrospective study. Based on the presence or absence of MVO on late gadolinium enhancement images, patients were divided into groups with MVO and without MVO. The infarct zone, adjacent zone, and remote zone were determined based on a myocardial 16-segment model. The radial strain (RS), circumferential strain (CS), and longitudinal strain (LS) of the global left ventricle (LV) and the infarct, adjacent, and remote zones were measured by CMR-FT from cine images and compared between patients with and without MVO using independent-samples t-test. Logistic regression analysis was used to assess the association of MVO with the impaired LV function.Results A total of 157 STEMI patients (mean age 56.66 ± 11.38 years) were enrolled. MVO was detected in 37.58% (59/157) of STEMI patients, and the mean size of MVO was 3.00 ±3.76 mL. Compared with patients without MVO (n =98 ), the MVO group had significantly reduced LV global RS (t= -4.30, P < 0.001), global CS (t= 4.99, P < 0.001), and global LS ( t= 3.51, P = 0.001). The RS and CS of the infarct zone in patients with MVO were significantly reduced (t= -3.38, P = 0.001; t= 2.64, P = 0.01; respectively) and the infarct size was significantly larger (t= 8.37, P < 0.001) than that of patients without MVO. The presence of LV MVO [OR= 4.10, 95%CI: 2.05 - 8.19, P<0.001) and its size [OR=1.38, 95%CI: 1.10-1.72, P=0.01], along with the heart rate and LV infarct size were significantly associated with impaired LV global CS in univariable Logistic regression analysis, while only heart rate (OR=1.08, 95%CI: 1.03 - 1.13, P=0.001) and LV infarct size (OR=1.10, 95%CI: 1.03 - 1.16, P=0.003) were independent influencing factors for the impaired LV global CS in multivariable Logistic regression analysis.Conclusion The infarct size was larger in STEMI patients with MVO, and MVO deteriorates the global and regional LV myocardial function.

Cardiac magnetic resonance-feature tracking technique can assess cardiac function and prognosis in patients with myocardial amyloidosis / 南方医科大学学报

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.

Left atrial function in healthy Chinese population by cardiac magnetic resonance-feature tracking imaging: A quantitative study / 第二军医大学学报

ObjectiveTo quantitatively evaluate the left atrial function in healthy Chinese population by cardiac magnetic resonance-feature tracking (CMR-FT). MethodsHealthy individuals with normal magnetic resonance examination results were enrolled according to the inclusion criteria. Cardiac long- and short-axis images and cine were obtained using semi-Fourier single-shot technique and balanced steady-state free precession sequence. The left atrial function parameters, including left atrial volume, ejection fraction, strain and strain rate, were measured by 2 independent observers. Two independent sample t test was used to compare the parameters between males and females. One-way analysis of variance was performed to compare the parameters among different age groups. ResultsA total of 63 volunteers were included in this study. Of 63 volunteers, 34 were males and 29 females; and 19 volunteers were aged≤29 years, 23 were aged 30-44 years and 21 were aged≥45 years. The anteroposterior diameter of left atrium was (26.1±4.5) mm, and the transverse diameter was (54.8±5.9) mm. The total ejection fraction of left atrium was (63.5±6.9)%, total strain was (45.9±11.7)%, and total strain rate was (1.5±0.5) s-1. The passive ejection fraction of left atrium was (24.6±9.1)%, passive strain was (22.2±8.1)%, and passive strain rate was (-0.8±0.3) s-1. The active ejection fraction of left atrium was (51.3±8.9)%, active strain was (23.7±9.2)%, and active strain rate was (-1.3±0.5) s-1. There were significant differences in the body surface area, the left atrial diameters, maximal volume and pre-active contraction volume between the males and the females (all P0.05). There were significant differences in the left atrial conduit function among the different age groups (all P0.6, and the Bland-Altman analysis showed better consistency between the two observers. ConclusionCMR-FT can be used to obtain parameters related to left atrial function in healthy Chinese population due to its high repeatability.