ABSTRACT
Objective:To quantify the left ventricular myocardial work in patients with repaired tetralogy of Fallot (TOF), and to evaluate the changes in left ventricular systolic function after TOF repair by pressure-strain loops (PSL).Methods:Seventy-six cases of children after TOF complete surgery in Shenzhen Children′s Hospital from September 2015 to September 2021 were analyzed retrospectively. There were 41 cases in the ≤4-year group and 35 cases in the >4-year group. Seventy-six healthy children with matched body surface area in the same period were selected as the control group. All subjects underwent complete echocardiography and quantitative analysis of left ventricular myocardial work, including global longitudinal strain (GLS), global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE). Compared with the normal control group, the changes of left ventricular myocardial work after TOF repair were analyzed. For patients with complete echocardiographic data before and after surgery, the correlation between postoperative left ventricular myocardial work and preoperative degree of right ventricular outflow tract (RVOT) obstruction was analyzed.Results:①In the ≤4-year group, compared with control subjects, GLS, GWI, GCW, GWE decreased, and GWW increased in patients with repaired TOF. All the differences were statistically significant [(-20.00±1.52)% vs (-21.59±1.73)%, (1 349.37±133.63)mmHg% vs (1 553.51±246.09)mmHg%, (1 589.39±167.85)mmHg% vs (1 749.12±249.45)mmHg%, 94.0%(94.0%, 95.0%) vs 96.0%(95.0%, 97.0%), (78.80±20.53)mmHg% vs (62.27±21.44)mmHg%; all P<0.05]. ②In >4-year group, compared with the control group, GLS, GWI, GWE decreased, and GWW increased in patients with repaired TOF. All the differences were statistically significant [(-19.89±1.66)% vs (-21.31±1.60)%, (1 486.09±172.42)mmHg% vs (1 713.14±227.05)mmHg%, 96.0%(94.0%, 96.0%) vs 97.0%(96.0%, 97.0%), 75.00(65.00, 95.00)mmHg% vs 55.00(42.00, 71.00)mmHg%; all P<0.05]. ③GWW was negatively correlated with preoperative RVOT diameter and RVOT-Z score( r=-0.422, -0.433; both P<0.05). GWE was positively associated with preoperative RVOT diameter and RVOT-Z score( r=0.441, 0.540; both P<0.05). ④GLS, GWI, GCW, GWW, GWE had good repeatability within and between observers.All the differences were not statistically significant (all P>0.05). Conclusions:Left ventricular systolic function in patients with repaired TOF is lower than that in healthy children of the same age by echocardiography PSL, although traditional indicators are still within the normal range. Patients with more severe RVOT obstruction before surgery have worse left ventricular systolic function after operation. Quantification of left ventricular myocardial work by echocardiography PSL is helpful for long-term follow-up of children after TOF repair.
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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 evaluate the myocardial work of patients with different degrees of coronary artery stenosis with normal left ventricular ejection fraction and no segmental ventricular wall motion abnormality by left ventricular pressure-strain ring (PSL), and to explore the clinical value of myocardial work parameters in predicting severe coronary artery stenosis.Methods:The data of 238 patients undergoing coronary angiography (CAG) in the Affiliated Hospital of Jining Medical University from December 2020 to August 2021 was prospectively collected. According to the results of CAG, the patients were divided into control group, moderate stenosis group, severe stenosis (1-2 branches) group, severe stenosis (complex multiple branches) group. Global longitudinal strain (GLS), global work index (GWI), global constructive work (GCW), global work waste (GWW) and global work efficiency (GWE) were measured by PSL. Univariate and multivariate logistics regression were used to analyze the influencing factors of severe coronary artery stenosis. The receiver operating characteristic (ROC) curve was constructed to analyze the predictive value of GLS, GWI, GCW, GWW and GWE for severe coronary artery stenosis.Results:The GLS, GWI, GCW and GWE in severe stenosis group were lower than those in control group and moderate stenosis group (all P<0.05), while GWW was higher than those in control group and moderate stenosis group (all P<0.05); the GWI, GCW and GWE in severe stenosis (complex multiple branches) group were lower than those in severe stenosis (1-2 branches) group (all P<0.05), while GWW was higher than those in severe stenosis (1-2 branches) group (all P<0.05). Multivariate logistic regression analysis showed that GWE was an independent influencing factor for severe coronary stenosis ( OR=0.266, P<0.05). Compared with GLS, GWI, GCW and GWW, GWE had the largest area under the curve (0.920) to predict severe coronary stenosis, with sensitivity of 92.24% and specificity of 73.77%. The intra observer and inter observer correlation coefficients of GWI, GCW, GWW and GWE analyzed by two ultrasound physicians were 0.916 and 0.907, 0.989 and 0.981, 0.932 and 0.955, 0.931 and 0.937, respectively, which showed good repeatability. Conclusions:PSL provides a new method for quantitative evaluation of left ventricular systolic function in patients with coronary artery stenosis. GWE can be used as a sensitive indicator to predict patients with severe coronary artery stenosis, and is worth to be popularized and applied in the clinical.
ABSTRACT
Based on 2D speckle tracking imaging (2D-STI), myocardium layer-specific strain can be used for quantitative assessment of myocardial function, but is load dependent. Added after-load (blood pressure) measurement to myocardium layer-specific strain, pressure strain loops (PSL) technique can effectively restrict load dependence and quantitatively analyze the work of whole and segmental myocardium. The research progresses of PSL in evaluation of myocardial work were reviewed in this article.