Evaluation Of Left Ventricular Function And Electromechanical Synchronism In Patients With Heart Failure By Dobutamine Stress Echocardiography

objective: To evaluate the left ventricular function and electromechanical synchronism in patients with congestive heart failure (CHF) by dobutamine stress echocardiography (DSE), and to investigate the correlation between the improvement of left ventricular function and electromechanical synchronism. Methods: eighteen patients with CHF (sinus rhythm, QRS≤120ms), including eight patients with idiopathic dilated cardiomyopathy (IDM) and ten patients with ischemic cardiomyopathy (ICM). The values of these patients were compared with fifteen age-matched healthy individuals. Patients with CHF underwent DSE (5-20μg/kg/min). Using 2-dimentional guide M-mode, pulse wave and TDI, transthoracic echocardiograms was recorded at rest and each stages of dobutamine infusion by HP Sonos 5500 color echocardiographic diagnostic system. We acquired left ventricular systolic (LVSEV) and diastolic end volume (LVDEV), left ventricular ejective fraction (LVEF), the peak velocity of early diastolic (Ev), Ev deceleration time (EDT), the atrial systolic transmitral flow (Av), Ev/Av, transmitral flow tracing (MVTI), isovolumic relaxtion time (IRT), isovolumic contraction time (ICT). From the echocardiography apical four-chamber and apical two-chamber views, the activities of the mitral annulus were recorded by TDI at four positions (septal , lateral ,anterior rand posterior wall). We measured the peak systolic velocity (S), the peak early diastolic velocity (E) and the atrial systolic wall motion velocity (A), and calculated the means of S, E, A (Sm, Em, Am). Systolic and diastolic electromechanical dispersion were derived from the maximal difference of Q-STDI and T-ETDI in the four positions. ECG parameters were measured manually, QRS duration, QT interval were corrected by Bazzett's formula, and calculated the QTc disperation. Results: 1.At rest, there was significant difference in left ventricular function and electromechanical synchronism between patients with CHF and the controls (P<0.01). During DSE, LVEF, Sm increased, LVSEV decreased, showed statistical difference in the stage of 10μg/kg/min. Reaching 20μg/kg/min, HR, MVTI, Em increased, E/Em decreased, with statistical difference. But electromechanical parameters didn't have statistical difference in each stage of patients with CHF. 2.ICM had more dyssynchronism than DCM. During DSE, electromechanical synchronism tended to be improved in DCM, while to be deteriorated in ICM. 3.In the pearson correlation model, QTcd significantly correlated with LVEF, Sm, Em, Q-STDI (P<0.05) ,correlation coefficient r﹦﹣0.48, r﹦﹣0.41, r﹦﹣0.36, r﹦0.46, r﹦0.29. Q-STDI significantly correlated with LVEF, Sm, Em (P<0.05) , correlation coefficient r﹦﹣0.52, r﹦﹣0.37, r﹦﹣0.47. Conclusion: 1.Patients with CHF having normal QRS duration (QRS≤120ms), shows significant electromechanical asynchronism, may fit for CRT. 2.ICM has more dyssynchronism than DCM. During DSE, electromechanical synchronism tend to be improved in DCM, while to be deteriorated in ICM. 3.TDI is a sensitive and accurate tool in evaluating ventricularsynchronism. 4.DSE is used to test patients taking β blockers, the stage 5-10μg/kg/min may be safe and effective.