Quantitative evaluation of left ventricular remodeling in left bundle branch block induced cardiomyopathy by multimodal imaging
10.3760/cma.j.cn131148-20240808-00431
- VernacularTitle:多模态影像学定量评估左束支传导阻滞性心肌病左心室重构程度
- Author:
Xiaoxian WANG
1
;
Changqing MIAO
;
Beibei GE
;
Mingxia LI
;
Fen CHEN
;
Fang XU
;
Ning ZHANG
;
Guanjun GUO
;
Wei XU
;
Wenzhi SHEN
;
Yingming ZHAO
;
Jing YAO
Author Information
1. 南京大学医学院附属鼓楼医院超声医学科，南京 210008
- Publication Type:Journal Article
- Keywords:
Left bundle branch block induced cardiomyopathy;
Left ventricular pressure-strain loop;
Single photon emission computed tomographg;
Left ventricular remo
- From:
Chinese Journal of Ultrasonography
2025;34(1):26-32
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To quantitatively evaluate the effects of left bundle branch block（LBBB）on left ventricular structure，function and myocardial perfusion using left ventricular pressure-strain loop and single photon emission computed tomography（SPECT），and to investigate the relationship between myocardial work，myocardial perfusion and pathological changes of left ventricular remodeling in left bundle branch block induced cardiomyopathy（LBBB-CM）.Methods:Fourteen male beagle dogs were selected，and the main trunk of the left bundle branch was ablated to create an LBBB dog model. Electrocardiogram（ECG），transesophageal echocardiography and arterial blood pressure data of LBBB dogs were collected before and 12 months after the ablation of left bundle branch trunk. Global and segmental myocardial work parameters were obtained by left ventricular pressure-strain loop. The differences of above parameters between baseline and 12 months after the ablation of left bundle branch were compared. SPECT was performed in LBBB dogs 12 months after the creation of LBBB. The hearts were harvested for anatomy observation and histopathological analysis in LBBB dogs and another 7 male beagle dogs（normal control group）matched by age and weight. The correlation between myocardial perfusion（percentage of regional tracer uptake）and myocardial work parameters，myocardial fibrosis in LBBB dogs were analyzed.Results:Compared with baseline，the left ventricular end-diastolic volume of 12 months after the ablation increased［（20.78 ± 5.32）ml vs（26.71 ± 7.94）ml， P = 0.003］，left ventricular ejection fraction decreased［（59.17 ± 5.67）% vs（47.69 ± 5.45）%， P<0.001］；left ventricular global/segmental longitudinal strain，global/segmental constructive work and global/segmental work efficiency decreased（all P<0.05），left ventricular global/segmental wasted work increased（all P<0.001）. Heterogenous perfusion defect was observed in LBBB dogs by SPECT，compared with lateral wall segments，the percentage of regional tracer uptake of septum was decreased（all P<0.05）. Gross anatomical and myocardial pathological changes were manifested as cardiomegaly，flaky or focal grayish thickening of endocardium，cardiomyocyte degeneration and fibrosis. Compared with normal control group，the collagen fiber volume fraction（CVF）in all segmental endocardium and partial segmental myocardium of LBBB dogs were significantly increased（all P<0.05）. Percentage of regional tracer uptake was positively correlated with segmental myocardial work（SMW）and segmental myocardial efficiency（SWE）（ r s = 0.49，0.31；both P<0.001），and negatively correlated with CVF and segmental wasted work（SWW）（ r s = -0.51，-0.49；both P<0.001）. Conclusions:Isolated LBBB is not benign，which can result in left ventricular remodeling，decreased cardiac constructive function，abnormal myocardial perfusion，endocardial fibrosis and myocardial fibrosis.The parameters of myocardial work assecsed by echocardiograpgy and myocardial perfusion，as non-invasive examination，can to some extent reflect the degree of left ventricular remodeling in LBBB-CM.
