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Abstract：
UNASSIGNED: Complete bundle branch block in individuals without structural heart disease is known as isolated complete bundle branch block. Isolated complete left bundle branch block (CLBBB) is correlated with ventricular dysfunction secondary to dyssynchrony; however, few studies have investigated isolated complete right bundle branch block (CRBBB), which was previously considered benign but was recently found to be associated with adverse cardiovascular outcomes. This study aimed to evaluate cardiac mechanical synchrony, and systolic and diastolic function in patients with isolated CRBBB and compare cardiac synchrony and function to patients with isolated CLBBB.
UNASSIGNED: This cross-sectional study was conducted at The First Hospital of China Medical University in Shenyang, China, from 2020 to 2021. A total of 44 isolated CRBBB patients, 44 isolated CLBBB patients, and 42 healthy subjects were enrolled in the study. Transthoracic echocardiography was performed in all subjects. Synchrony parameters, including the mechanical dispersion of the right ventricle [the standard deviation of time to the peak longitudinal strain of six right ventricular (RV) segments] and atrioventricular dyssynchrony parameter [the ratio of left ventricular (LV) diastolic filling time to the time interval between two adjacent R waves (RR interval) measured by tissue Doppler imaging]. RV and LV function were assessed by the global longitudinal strain (GLS) of six RV segments and 18 LV segments, and the ratio of the peak early diastolic flow velocity to annular velocity (E/e\') of the tricuspid valve and mitral valve. Statistical analyses were performed, including an analysis of variance, Pearson correlation analysis, and linear regression analysis.
UNASSIGNED: Compared with the healthy subjects, the mechanical dispersion of the right ventricle was significantly increased, and ventricular function was impaired as evidenced by the decreased RV GLS and LV GLS, and the increased E/e\' of the tricuspid valve and mitral valve in the isolated CRBBB patients (all P<0.001). Moreover, compared with the isolated CLBBB patients, the mechanical dispersion of the right ventricle and E/e\' of the tricuspid valve were increased, and RV GLS was significantly reduced in the isolated CRBBB patients (all P<0.001). Mechanical dispersion of the right ventricle was independently associated with RV GLS [coefficient, 0.13; 95% confidence interval (CI): 0.004-0.26; P=0.04] in the isolated CRBBB patients. RV GLS (coefficient, 0.10; 95% CI: 0.01-0.20; P=0.03) and the ratio of the LV diastolic filling time to the RR interval measured (coefficient, -0.30; 95% CI: -0.53 to -0.07; P=0.01) were independent factors of LV GLS.
UNASSIGNED: The isolated CRBBB patients had impaired cardiac mechanical synchrony and ventricular function, and more decreased RV synchrony and function than the isolated CLBBB patients. Right intraventricular synchrony was independently associated with RV systolic dysfunction in patients with isolated CRBBB. Atrioventricular synchrony and RV systolic function were independently associated with the LV systolic function. Therefore, comprehensive evaluations of echocardiography results and close monitoring is required for isolated CRBBB patients.
UNASSIGNED: This cross-sectional study was conducted at The First Hospital of China Medical University in Shenyang, China, from 2020 to 2021. A total of 44 isolated CRBBB patients, 44 isolated CLBBB patients, and 42 healthy subjects were enrolled in the study. Transthoracic echocardiography was performed in all subjects. Synchrony parameters, including the mechanical dispersion of the right ventricle [the standard deviation of time to the peak longitudinal strain of six right ventricular (RV) segments] and atrioventricular dyssynchrony parameter [the ratio of left ventricular (LV) diastolic filling time to the time interval between two adjacent R waves (RR interval) measured by tissue Doppler imaging]. RV and LV function were assessed by the global longitudinal strain (GLS) of six RV segments and 18 LV segments, and the ratio of the peak early diastolic flow velocity to annular velocity (E/e\') of the tricuspid valve and mitral valve. Statistical analyses were performed, including an analysis of variance, Pearson correlation analysis, and linear regression analysis.
UNASSIGNED: Compared with the healthy subjects, the mechanical dispersion of the right ventricle was significantly increased, and ventricular function was impaired as evidenced by the decreased RV GLS and LV GLS, and the increased E/e\' of the tricuspid valve and mitral valve in the isolated CRBBB patients (all P<0.001). Moreover, compared with the isolated CLBBB patients, the mechanical dispersion of the right ventricle and E/e\' of the tricuspid valve were increased, and RV GLS was significantly reduced in the isolated CRBBB patients (all P<0.001). Mechanical dispersion of the right ventricle was independently associated with RV GLS [coefficient, 0.13; 95% confidence interval (CI): 0.004-0.26; P=0.04] in the isolated CRBBB patients. RV GLS (coefficient, 0.10; 95% CI: 0.01-0.20; P=0.03) and the ratio of the LV diastolic filling time to the RR interval measured (coefficient, -0.30; 95% CI: -0.53 to -0.07; P=0.01) were independent factors of LV GLS.
UNASSIGNED: The isolated CRBBB patients had impaired cardiac mechanical synchrony and ventricular function, and more decreased RV synchrony and function than the isolated CLBBB patients. Right intraventricular synchrony was independently associated with RV systolic dysfunction in patients with isolated CRBBB. Atrioventricular synchrony and RV systolic function were independently associated with the LV systolic function. Therefore, comprehensive evaluations of echocardiography results and close monitoring is required for isolated CRBBB patients.
摘要：
■在没有结构性心脏病的个体中，完全束支传导阻滞被称为孤立的完全束支传导阻滞。孤立的完全性左束支传导阻滞（CLBBB）与继发于不同步的心室功能障碍有关；然而，很少有研究调查孤立的完全右束支传导阻滞（CRBBB），以前被认为是良性的，但最近发现与不良心血管结局相关。本研究旨在评估心脏机械同步性，孤立性CRBBB患者的收缩和舒张功能，并比较孤立性CLBBB患者的心脏同步性和功能。
■这项横断面研究是在位于沈阳的中国医科大学附属第一医院进行的,中国,从2020年到2021年。共有44例分离的CRBBB患者，44例孤立的CLBBB患者，42名健康受试者被纳入研究。所有受试者均进行经胸超声心动图检查。同步参数，包括右心室的机械离散度[至六个右心室（RV）节段的峰值纵向应变的时间的标准偏差]和房室不同步参数[左心室（LV）舒张期充盈时间与通过组织多普勒成像测量的两个相邻R波之间的时间间隔（RR间隔）之比]。通过6个RV节段和18个LV节段的整体纵向应变（GLS）评估RV和LV功能。以及三尖瓣和二尖瓣的舒张早期峰值流速与环形速度（E/e\'）之比。进行了统计分析，包括方差分析，皮尔逊相关分析，和线性回归分析。
■与健康受试者相比，右心室的机械离散度显着增加，和心室功能受损，如RVGLS和LVGLS降低所证明，孤立性CRBBB患者的三尖瓣和二尖瓣E/e增加（均P<0.001）。此外，与孤立的CLBBB患者相比，右心室的机械离散度和三尖瓣的E/e增加，在分离的CRBBB患者中，RVGLS显着降低（均P<0.001）。右心室的机械离散度与RVGLS独立相关[系数，在分离的CRBBB患者中，0.13；95％置信区间（CI）：0.004-0.26；P=0.04]。RVGLS(系数，0.10;95％CI：0.01-0.20;P=0.03）和测量的LV舒张期充盈时间与RR间期的比率（系数，-0.30；95％CI：-0.53至-0.07；P=0.01）是LVGLS的独立因素。
■孤立的CRBBB患者心脏机械同步性和心室功能受损，与孤立的CLBBB患者相比，RV同步性和功能降低更多。右心室同步性与孤立性CRBBB患者的右心室收缩功能障碍独立相关。房室同步性和RV收缩功能与LV收缩功能独立相关。因此,对于孤立的CRBBB患者,需要对超声心动图结果进行全面评估并密切监测.
■这项横断面研究是在位于沈阳的中国医科大学附属第一医院进行的,中国,从2020年到2021年。共有44例分离的CRBBB患者，44例孤立的CLBBB患者，42名健康受试者被纳入研究。所有受试者均进行经胸超声心动图检查。同步参数，包括右心室的机械离散度[至六个右心室（RV）节段的峰值纵向应变的时间的标准偏差]和房室不同步参数[左心室（LV）舒张期充盈时间与通过组织多普勒成像测量的两个相邻R波之间的时间间隔（RR间隔）之比]。通过6个RV节段和18个LV节段的整体纵向应变（GLS）评估RV和LV功能。以及三尖瓣和二尖瓣的舒张早期峰值流速与环形速度（E/e\'）之比。进行了统计分析，包括方差分析，皮尔逊相关分析，和线性回归分析。
■与健康受试者相比，右心室的机械离散度显着增加，和心室功能受损，如RVGLS和LVGLS降低所证明，孤立性CRBBB患者的三尖瓣和二尖瓣E/e增加（均P<0.001）。此外，与孤立的CLBBB患者相比，右心室的机械离散度和三尖瓣的E/e增加，在分离的CRBBB患者中，RVGLS显着降低（均P<0.001）。右心室的机械离散度与RVGLS独立相关[系数，在分离的CRBBB患者中，0.13；95％置信区间（CI）：0.004-0.26；P=0.04]。RVGLS(系数，0.10;95％CI：0.01-0.20;P=0.03）和测量的LV舒张期充盈时间与RR间期的比率（系数，-0.30；95％CI：-0.53至-0.07；P=0.01）是LVGLS的独立因素。
■孤立的CRBBB患者心脏机械同步性和心室功能受损，与孤立的CLBBB患者相比，RV同步性和功能降低更多。右心室同步性与孤立性CRBBB患者的右心室收缩功能障碍独立相关。房室同步性和RV收缩功能与LV收缩功能独立相关。因此,对于孤立的CRBBB患者,需要对超声心动图结果进行全面评估并密切监测.
