| Background and objectsPremature ventricular beat (PVB) is a common cardiac arrhythmia in clinical practice,it may occur in the healthy persons and the patients with structural heart diseases, and those that happen in the healthy persons without structural heart disease, are called as idiopathic PVB. Previous studies have used traditional ultrasound techniques to evaluate the cardiac function of the patients with idiopathic PVB. However, these methods are influenced by many subjective or objective factors, and now the tissue Doppler imaging, as a convenient and accurate method, more and more be used to evaluate the systolic and diastolic function of the heart.The objects of this study is to evaluate the changes of cardiac function in PVB patients without structural heart diseases by measuring the index of motion velocity and time interval using pulsed wave-tissue Doppler imaging (PW-TDI) techniques.Methods1. Subjects with isolated PVB group(n=30) and controls group(n=30) were enrolled in this study. Through the physical examination and related laboratory examination, all the subjects were confirmed that their heart structure and the function are normal.2. All subjects received the test of electrocardiogram. The time internal of R-R ,and the coupling interval were measured.3. All subjects received the test of Two-Dimensional echocardiography and PW-TDI.3.1 LV end-diastolic diameters, RV end-diastolic diameters and inter-ventricular septum and posterior wall thicknesses were measured from the parasternal long-axis projection. LV end-systolic and diastolic volumes, RV end-systolic and diastolic volumes were obtained from the apical four-chamber views. LV ejection fraction was calculated by machine.3.2 Velocity index and time interval index associated with systolic and diastolic function at the basal segments of left and right ventricular were obtained from PW-TDI. The index of motion velocity include systolic peak velocites (Sm), time velocity integral(TVI),peak velocity of the early relaxation wave (Em),peak velocity of the later relaxation wave(Am) and Em/Am ratio. The index of time interval was as follows:electromechanical delay (EMD),time from Q wave to the peak of the systolic wave(Q-Sm), isovolumic contraction time (IVCT) and ejection time (ET),and all indexes in the PVB group were recorded during the normal sinus beat, PVB and post-PVB sinus beat.Results1. There were no significant differences in age and gender between PVB group and control group(P>0.05).2 . All other echocardiogaphic variables from Two-Dimensional echocardiography were also similar between two groups(P>0.05).3. PW-TDI3.1 Motion velocity index:there were no significant differences in Sm,Vmean,TVI,Em,Am and Em/Am ratio between the control group and PVB group in the normal sinus beat(P>0.05).3.2 In all sites, compared to the normal sinus beat, Sm,TVI,Em and Em/Am ratio within PVB group were all significantly decreased(P<0.05), while Sm,TVI,Em in the post-PVB sinus beat were significantly increased (P<0.05).However, there were no significant differences of Am in each site among the normal sinus beat, PVB and the post-PVB sinus beat(P>0.05).3.3 There were no significant differences in EMD,Q-Sm,IVCT and ET between the control group and PVB group in the normal sinus beat(P>0.05).3.4 At the basic level of every site, compared to the normal sinus beat, EMD,Q-Sm,IVCT in PVB were all significantly extended(P<0.05),while ET was decurtate(P<0.05).3.5 Make linear correlation analysis between the coupling interval and changes of Sm during PVB, found that in all of the 7 sites,they had good relevance(P<0.05).3.6 Compared to the right ventricle origin group, Em and Em/Am in the left venteicle origin group were significantly decreased at the basic level of PS,AS and LVIW among the normal sinus beat (P<0.05).And among the PVB, these indexes were significantly decreased at the basic level of LVLW,PVS,RVLW,AVS,LVPW and LVAW (P<0.05).3.7 In all of 7 sites, there were no significant differences in EMD,Q-Sm, IVCT and ET between the two groups among the normal sinus beat (P>0.05);and among the PVB, compared to the right ventricle origin group, IVCT in the left venteicle origin group were significantly extended at the basic level of AVS and LVIW (P<0.05).ConclusionPVB could significantly influence the systolic and diastolic function of ventricle, and the effects of PVB derived from left ventricle on cardiac function were more remarkable than that of PVB from right ventricle on cardiac function. |
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