Application Of New Cardiovascular Magnetic Resonance Imaging Technology In Preclinical Lesion

Objectives To investigate the correlation between the extent of excessive trabeculation assessed by fractal dimension(FD)and myocardial contractility assessed by cardiac MRI feature tracking in patients with excessive trabeculation and normal left ventricular ejection fraction(LVEF).Methods Forty-one patients with excessive trabeculation and normal LVEF(≥50%)and 41 healthy controls were retrospectively included.All patients fulfilled three available diagnostic criteria on MRI.Cardiac MRI feature tracking was performed on cine images to determine left ventricular peak strains in three directions:global radial strain(GRS),global circumferential strain(GCS),and global longitudinal strain(GLS).The complexity of excessive trabeculation was quantified by fractal analysis on short-axis cine stacks.Results Compared with controls,patients with excessive trabeculation had impaired GRS,GCS,and GLS(all P<0.05).The global,maximal,and regional FD values of the patients were all significantly higher than those of the controls(all P<0.05).Global FD was positively correlated with the end-diastolic volume index,end-systolic volume index,and stroke volume index(r=0.483,0.505,and 0.335,respectively,all P<0.05),but negatively correlated with GRS and GCS(r=-0.458 and 0.508,respectively,both P<0.001).Moreover,apical FD was also weakly associated with LVEF and GLS(r=-0.249 and 0.252,respectively,both P<0.05).Conclusion In patients with excessive trabeculation,left ventricular systolic dysfunction was detected early by cardiac MRI feature tracking despite the presence of normal LVEF and was associated with excessive trabecular complexity assessed by FD.Objectives Myocardial fibrosis is implicated as a potential substrate responsible for arrhythmias.This study aimed to investigate myocardial fibrosis assessed by T1 mapping in patients with apparently idiopathic premature ventricular complexes(PVC),and to determine the relationship between this tissue biomarker and PVC features.Methods Patients with frequent PVC(>1,000/24 h)who underwent cardiac magnetic resonance imaging(MRI)between 2020 and 2021 were retrospectively evaluated.Patients were included if they had no indicator of known heart diseases on MRI.Sex-and agematched healthy subjects underwent noncontrast MRI with native T1 mapping.High PVC burden was defined as the percentage of PVC>20%/24 h.Results A total of 70 patients and 70 healthy controls were included.Global T1 value was significantly higher in patients than in controls(P<0.001).Extracellular volume fraction was 26.03%± 2.16%in the patients.Moreover,global T1 value showed a stepwise increase in PVC tertiles(P=0.03)but not for extracellular volume(P=0.85).Patients with a non-left bundle branch block(LBBB)inferior axis morphology showed higher global native T1 values than LBBB inferior axis pattern(P=0.005).In addition,global T1 values correlated significantly with PVC burden(r=0.28,P=0.02).In the multivariate analysis,global T1 value independently correlated with high PVC burden(odds ratio:1.22 per 10-ms increase,P=0.02).Conclusion Increased global T1,a marker of interstitial fibrosis,was detected in patients with apparently idiopathic PVC and was significantly associated with non-LBBB inferior axis morphology and high PVC burden.