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Objective:To evaluate the left ventricular myocardial strain and mechanical synchrony in patients suspected of non-ST-segment elevation acute coronary syndrome (NSTE-ACS) by two-dimensional speckle tracking imaging (2D-STI) and real-time three-dimensional echocardiography (RT-3DE), and to investigate the value of combined echocadiographic parameters in predication of significant coronary artery stenosis.Methods:A total of 95 patients suspected of NSTE-ACS, definitely planed to run coronary angiography (CAG) within 24-72 hours of admission were recruited in the Department of Cardiology, General Hospital of the Southern Theatre Command, PLA from December 2020 to June 2021. Regular echocardiography exam, 2D-STI and RT-3DE were performed prior to CAG.Global longitudinal peak strain (GLPS), territorial longitudinal peak strain (T RCALPS, T LADLPS, T LCXLPS) were computed by 2D-STI; the maximal difference of time to minimal systolic volume of 16-segments (Tmsv16-Dif), standard deviation of time to minimal systolic volume of 16-segment (Tmsv16-SD) and heart rate adjusted standard deviation of time to minimal systolic volume of 16-segment (Tmsv16-SD/R-R) were obtained by RT-3DE. The patients were divided into two groups according to the degree of coronary stenosis.Significant coronary artery stenosis group was defined as ≥70% of left main or any other main branch luminal narrowing ( n=53), non-significant coronary artery stenosis group was defined as <70% of luminal narrowing ( n=42). The differences of general clinical features, left ventricular strain and mechanical synchronization parameters between the two groups were compared. A binary logistic regression model was established to draw the ROC curve for predicting the severity of coronary stenosis by single and combined ultrasound parameters, and calculate the area under the ROC curve (AUC). Results:Compared with non-significant coronary artery stenosis group, GLPS were significantly reduced, while Tmsv16-SD, Tmsv16-Dif and Tmsv16-SD/R-R were significantly increased in sginificant coronary artery stenosis group (all P<0.05). The AUC of GLPS and Tmsv16-SD, Tmsv16-Dif and Tmsv16-SD/R-R for predicting significant coronary stenosis in suspected NSTE-ACS patients were 0.78, 0.69, 0.71 and 0.67, respectively. The result of joint test analysis for the dignosis of NSTE-ACS suspected significant coronary stenosis were as follows: the specificity of tandem test was 90.5%; the sensitivity of parallel test was 83.0%; the sensitivity, specificity and AUC of GLPS-Tmsv16-Dif joint index prediction test were 90.7%, 60.1% and 0.82 (95% CI=0.73-0.89) with 0.508 as Youden index. Conclusions:NSTE-ACS suspected patients with significant coronary stenosis are often accompanied by impaired left ventricular myocardial strain and mechanical dyssynchrony. A simple combination of left ventricular myocardial strain and contractility synchronization improves noninvasive prediction of high-risk coronary artery stenosis in suspected NSTE-ACS, which maybe helpful for screening patients requiring invasive examination.
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Objective:To evaluate the effects of different pacing modes (unipolar/bipolar) under left bundle branch pacing(LBBP) on ventricular mechanical synchrony and myocardial work using the pressure-strain loop technique.Methods:Twenty-nine patients with LBBP due to symptomatic bradycardia were collected as LBBP group in Sun Yat-sen Memorial Hospital of Sun Yat-sen University from December 2018 to July 2020. Another 29 matched patients with right ventricular pacing (RVP) during the same period were also included as a RVP group. Each LBBP patient was programmed to different pacing modes (uni-/bio-polar) within 1 week after the operation.Under each pacing mode, the inter- and intra-ventricular mechanical synchronization were evaluated. Meanwhile, the global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) were obtained by the left ventricular pressure-strain loops technique.Results:Compared with the RVP group, the mechanical synchrony in the LBBP group was significantly improved (all P<0.05). GWI, GCW, and GWE increased, while GWW decreased, and the differences were statistically significant (all P<0.05), there were no significant differences in ventricular mechanical synchronization, GWI, GCW, GWE, and GWW between unipolar and bipolar pacing in the LBBP group (all P>0.05), there were no significant differences in these parameters when increasing output voltage (all P>0.05). Conclusions:LBBP induces better mechanical synchronization and higher myocardial work efficiency than RVP. Different LBBP pacing modes do not affect ventricular mechanical synchronization and myocardial work efficiency.
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Objective To test synchronization of cardiac mechanical contraction by means of advanced echocardiography and investigate the correlation of left ventricular ejection fraction (LVEF) and the indexes of mechanical dyssynchrony, and the relationship between DTI, STI and RT-3DE.Methods Control group (20 cases), chronic heart failure with a widened QRS complex (12 cases) and chronic heart failure with a shortened QRS duration (10 cases) were selected. We evaluated mechanical dyssynchrony with the DTI, the STI and the RT-3DE, and analyzed the correlation between the improvement degree of cardiac function and indexes of mechanical dyssynchrony, and the correlation between DTI, STI and RT-3DE. Results (1) In CHF groups (including shortened QRS group and widened QRS group), the indexes of synchronization of cardiac mechanical contraction were higher than control group ( 0.05) . (3) In CHF groups (including shortened QRS group and widened QRS group), the indexes of mechanical dyssynchrony before operation were higher more than after operation ( 0.05) . (5) There was a significant negative correlation between the LVEF and the indexes of mechanical dyssynchrony (<0.01) . (6) .In the indexes of synchronization of cardiac mechanical contractions, there are significant positive correlations between the DTI, the STI and the RT-3DE ( <0.01) . Conclusion Echocardiography can be used to screen CHF patients,and patients with left ventricular synchronous (including shortened QRS duration) can also be benefited from CRT.
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Objective To investigate the clinical value of the gated blood pool imaging phase analysis method in the evaluation of left ventricular mechanical synchronization in patients with chronic heart failure. Methods A total of 169 patients with chronic heart failure were enrolled in our study , using gated blood pool imaging phase analysis method to obtain left ventricular phase angle width ( PHB) and left ventricular phase angle standard deviation ( PSD) as evaluating left ventricular mechanical synchrony index; using tissue Doppler imaging (TDI) measurement of the standard deviation of systolic peak time(Ts-SD) of each segment by using the current prevailing 12 non-apical segments analysis method as evaluating left ventricular mechanical synchrony index, and parameters derived from both methods were compared. Results LVPHB was highly correlated with Ts-SD (r = 0. 83 ,P = 0. 000 ) . LVPSD was modestly correlated with Ts-SD ( r - 0. 69, P = 0. 000) . The ejection fraction measured by echocardiography was (42.93 ± 14. 89) % ,which was significantly higher than that measured by ERNA (39. 76 ± 17. 89)% (P <0. 01). Conclusions The evaluation of left ventricular mechanical synchrony in patients with chronic heart failure by the gated blood pool imaging can provide similar information with TDI, which can simultaneously measure two ventricular functions and get more accurate measurement of ejection fraction. Cardiac resynchronization therapy patients can be identified by combining two kinds of approaches, and cardiac resynchronization therapy responders could be improved as well. More patients with heart failure can benefit from cardiac resynchronization therapy therapy.