ABSTRACT
Objective To assess the left ventricular synchronization and global systolic function in patients with implanted dual-chamber (DDD) mode cardiac pacemakers by real-time three-dimensional echocardiography(RT-3DE). Methods Left ventricular systolic synchronization and global function were evaluated in 20 patients with implanted DDD mode cardiac pacemakers and 20 normal people by RT-3DE. The left ventricular end-diastolic volume (LEDV), end-systolic volume ( LESV), stroke volume (SV), left ventricular ejection fraction (LVEF), the mean value of time from the start of electrocardiographic QRS wave to the point of minimal systolic volume (Tmean) of the 17 segments and those standard deviation(T-SD),the maximal difference of time among all 17 segments(Tmax) were obtained by RT-3DE. Results Compared with control group, LESV was significantly increased,SV, LVEF were significantly decreased and T-SD,Tmax were significantly prolonged (P <0.01 ). There were no differences in LEDV and Tmean between the two groups (P>0.05). In patients group,LVEF correlated closely with T-SD (r =-0.674, P<0.05) and Tmax (r = - 0. 634, P < 0. 05). Conclusions There were left ventrieular systolic asychronization and global systolic dysfunction in patients with implanted dual-chamber (DDD) mode cardiac pacemakers,which could be assessed by RT-3DE.
ABSTRACT
Objective To detect the clinical value of evaluating myocardial viability in patients with old myocardial infaretion(OMI) by measuring myocardial isovolumie contraction motion indices with tissue Doppler imaging(TDI) under the quiescent condition. Methods The myocardial isovolumic contraction motion indices of 30 normal subjects and 30 patients with OMI were examined by TDI. The sample gate was located at left ventricular postero-septal,lateral,anterior,inferior,antero-septal and posterior walls in basal and middle segments separately. The peak positive and negative veiocities(VIVC1 ,VIVC2 ) during myocardial isovohimic contraction phase, and the difference(DIVC) between VIVC1 and VIVC2 were measured, which were analysed combined with the viable fraction(VF) calculated by single photon emission computed tomography (SPECT). Results VIVC1, DIVC were significantly decreased,and VIVC2 was significantly increased in infarct zones of patients with OMI than those of the normal subjects( P <0.05). Compared with normal subjects, myocardial isovolumic contraction motion indices of non-infarct wails in patients with OMI were steady( P >0.05). In OMI group,DIVC of short axis was significantly decreased than that in long axis( P <0.05). Statistic analysis showed that DIVC values on both of short and long axis had significant positive correlations with VF derived from SPECT,and the correlation coefficients were 0. 837 ( P<0. 001) and 0. 797( P<0. 001 ) ,respectively. The sensibility and specificity of evaluating viable myocardium was 75% and 75% separately supposing the cutoff of DIVC on short axis was more than - 1.50,and the sensibility and specificity was 77. 8% and 87.5% separately if the cutoff of DIVC on long axis was more than 0.92. Conclusions Myocardial isovolumic contraction's TDI of infarct zones in patients with OMI had characteristic changes. DIVC on both of short and long axis could be as a new method of evaluating myocardial viability.