Clinical Application In Ultrasound Technology Assessment Movement Of The Heart Synchrony And Cardiac Resynchronization Therapy

BACKGROUND Cardiac synchronicity in patients with heart failure and bundle branch block and its value in cardiac resynchronization therapy have been widely evaluated nowadays. However, data on the cardiac synchronicity and cardiac function are scarce for subjects with isolated bundle branch block.OBJECTIVE Using tissue Doppler imaging and conventional echocardiographic technique, we examined the cardiac function and synchronicity in individuals with isolated right bundle branch block (RBBB) or left bundle branch block (LBBB) and assessed the relationship between QRS duration and synchronicity.METHODS Subjects with isolated RBBB (n=20), LBBB (n=10) and normal controls (n=20) were studied with conventional echocardiography and tissue Doppler imaging. The difference between aortic and pulmonary pre-ejection intervals was defined as interventricular delay (IVD). Parameters in septum and lateral wall were measured using tissue Doppler imaging, including peak myocardial sustained systolic velocity (S_m), peak early (Em) and late (A_M) diastolic velocities as well as time to peak velocities (T_S, T_e and T_a). The septum-to-lateral delay in T_S, AT_S, was calculated as an indicator of intraventricular asynchronicity.RESULTS Right ventricle systole was about 6ms later than left ventricle in subjects with normal ECG. In the RBBB group, right ventricle lagged about 41...