| Part I. Evaluation of Left Ventricle Torsional Function in Right Ventricle Volume Overload Individuals Using Two-Dimensional Speckle Tracking ImagingSection I. Evaluation of Left Ventricle Torsional Function in Patients with Secundum Atrial Septal Defect Using Two-dimensional Speckle Tracking ImagingBackgrounds:A novel ultrasound speckle tracking imaging (STI) allows the noninvasive assessment of left ventricular (LV) torsional deformation. There is no data available on the impact of right ventricular (RV) volume overload on LV twist and untwisting in atrial setpal defect (ASD). This study sought to evaluate LV torsional deformation using STI method in patients with ASD and normal pulmonary pressure.Methods:Forty-five asymptomatic adults with isolated secundum ASDs were enrolled in this study. Using commercially available 2-dimensional strain software, we analyzed basal and apical LV short-axis images in these patients with ASD and 45 age-and sex-matched normal subjects. LV twist was defined as the difference between LV apical and basal rotation.Results:As expected, patients with ASD had significantly smaller LV end-diastolic volume (62.0±1.1 ml vs.69.9±10.1 ml, P=0.001) and lower LV ejection fraction (EF) values (65.4±0.5% vs.69.4±0.6%, P=0.001) in comparison with the matched controls. The apical rotation parameters were similar between two groups. However, the peak basal rotation was significantly depressed (-5.4±2.8°vs.-6.9±2.6°,P＜0.001) and the time to peak rotation was significantly delayed (118.3±18.8% vs.96.1±12.6% of systolic period, P＜0.001) in patients with ASD. The peak basal initial counterclockwise rotation in ASD group was significantly higher (5.1±3.3°vs. 1.8±1.4°, P＜0.001) and its duration was longer (75.4±26.7% vs. 42.5±24.4% of systolic period, P＜0.001) than that in control group. LV peak twist was also reduced significantly in patients with ASD (11.9±5.9°vs.14.6±3.5°, P<0.005) in comparison with the matched controls while the LV untwisting parameters including peak untwisting rate and time to peak untwisting rate were similar between two groups.Conclusions:LV systolic twist was reduced but distolic untwisting remained unchanged in patients with ASD. The depressed LV twist was mainly due to the altered basal rotation which was characterized by a reduced and delayed clockwise rotation following an abnormally enhanced and extended initial counterclockwise rotation during early systole.Section II. Evaluation of Left Ventricle Torsional Function in Patients Undergoing Transcatheter Closure of Secundum Atrial Septal Defect Using Two-dimensional Speckle Tracking ImagingBackgrounds:Left ventricular (LV) torsional deformation plays an important role with respect to LV ejection and filling. However, no data are available on the impact of overload relief on LV torsional deformation after transcatheter ASD closure. This study sought to evaluate LV twist and untwisting before and early after device closure of ASD using the speckle tracking imaging (STI).Methods:We acquired basal and apical LV short-axis ultrasound images in 30 patients before and 1-day after transcatheter ASD closure. All data were offline analyzed with Echopac 7.0 software.Results:LV end-diastolic volume (69.6±6.3 ml vs.62.1±5.0 ml, P=0.007) and LV ejection fraction (69.3±5.7% vs.65.9±5.2%, P=0.007) were increased significantly after successful closure of ASD while end-systolic volume was unchanged (P> 0.005). After transcatheter ASD closure, there was no significant difference in peak apical rotation and time to the peak (P> 0.005 for both). However, a significantly improved basal rotation was recorded, including significantly increased peak clockwise rotation (-7.1±3.2°vs.-5.4±2.9°, P= 0.0014), decreased initial counterclockwise rotation (2.0±1.8°vs.5.1±3.2°, P< 0.001) and shortened time to peak clockwise rotation (105.5±16.5% vs.118.0±18.5% of systolic period, P= 0.001). LV twist was significantly improved in patients with ASD after the device closure (16.1±6.7°vs.12.2±6.3°, P=0.001), whereas there was no significant difference in peak untwisting rate, time to the peak and untwisting during IVRT (P> 0.05 for all).Conclusions:LV systolic twist could be significantly improved but diastolic untwisting remained unchanged after transcatheter ASD closure. This improvement was mainly attributed to the improved LV basal rotation rather than the unchanged apical rotation.Part II. Experimental and Clinical Evaluation of Left VentricleTorsional Function in Right Ventricle Pressure Overload Individuals Using Two-Dimensional Speckle Tracking ImagingObjective:A novel ultrasound speckle tracking imaging (STI) allows the noninvasive assessment of left ventricular (LV) torsional deformation. There is little data available on the impact of right ventricular (RV) pressure overload on LV twist and untwisting in pulmonary arterial hypertension (PH). This study sought to evaluate LV torsional deformation using STI method in dogs and patients with PH.Methods:Animal experiments:Following right heart catheterization, chronic pulmonary hypertension model was established in 12 healthy Beagle dogs by the injection of monocrotaline dehydrogenation 2mg/kg into the right ventricular through right heart catheter. Repeated right heart catheterization was performed after 8 weeks. Conventional echocardiography images were collected using a GE Vivid 7 ultrasound system with a M3S probe (1.7-3.4 MHz) before the initial catheterization and at 8 weeks follow-up. Offline analysis were performed with EchoPAC 7.0 sofeware (GE-Vingmed, Horton, Norway) to obtain the associated speckle tracking parameters.Clinical research:Echocardiography and right heart catheterization were performed in 24 patients with pulmonary hypertension (5 males, aged 33±15 years) and 25 normal controls (5 males, aged 32±14 years). Conventional echocardiography images were collected using a GE Vivid 7 ultrasound system with a M3S probe (1.7-3.4 MHz)before the initial catheterization and at 8 weeks folloW—up.Offline analysis were performed with EchoPAC 7.0 sofeware(GE-Vingmed,Horton,Norway) to obtain the associated speckle tracking parameters.Results:Animal experiments:Of the 12 dogs,chronic pulmonary hypertension model was successfully established in 8 survivors(At 8 weeks,PASP=21.63±3.58 mmHg, PVR=391.00±240.57 dyn.s/cm5).Compared with the initial parameters,ACT was shortened(16.3±2.9 vs 12.8±2.5% RR,p=0.006)and TAPSE was decreased signifcantly(1.11±0.16 vs 0.79±0.22 cm,p=0.010)at 8 weeks,while the left and right ventricular morphology had no significant change.STI analysis showed that the basal rotation angle decreased significantly afer the pulmonary hyperension occured (-4.8±2.9 vs±2.6±2.7°,p=0.021),and both the apical and global untwisting rates of left ventricle were also reduced significantly(-99.0±35.8 vs-60.9±28.7°/s,p= 0.024；-145.2±55.1 vs-87.5±34.3°/s,p=0.018).CIinical research:All patients in the PH group were diagnosed as severe pulmonary hypertension(PASP=98.4±27.7mmHg,PVR=1337.4±765.8 dyn-s/cm5),with enlarged right ventricle, reduced left ventricular end-diastolic and end-systolic volumes(44.5±15.1 vs 70.6±15.6 ml,p<0.001；13.4±7.1 vs 22.0±5.1 ml,p <0.001,respectively)and similar left ventricular EF compared with the control.The TAPSE(1.44±0.32 vs 2.28±0.31 cm,p<0.001)was lower and the Tei indexes were higher in the PH group.STI analysis showed that,as compared with the control,the patients with PH were associated with reduced basal,apex and global torsional angles of lefc ventricle(basal-5.5±3.1 vs-7.0±2.7.,p=0.042；apical 9.3±4.8 vs 14.4±5.8°,P=0.005；global 13.0±5.O vs 20.1±6.8.,p<0.001；respectively),delayed time to the peak torsion at the base,(124.0±31.5 vs 102.7±17.5% systolic period,P =0.022),shortened time to the peak torsion at the apex(82.3±23.2 vs 98.6±10.3% systolic,p=0.015),lower untwisting rate(-52.4±l9.6 vs-70.8±28.0./s,P=0.019) and delayed time to the peak at the base(135.2±17.6 vs 122.9±9.3％systolic,p= 0.017),lower torsional rate at the apex of left ventricular(97.2±38.3 vs 127.0±39.2./s,p=0.022). Both the absolute value and systolic period-standardized percentage of the time difference to the peak torsion between the apex and the base PH group were longer than those in the control(-56.8±62.0 vs-6.8±25.4ms,p= 0.001；-79.2±46.5 vs-44.5±24.6% systolic,p=0.004).The peak torsional rate and the time to the peak at the base were negatively correlated with the pulmonary systolic pressure (r=-0.610, P= 0.02; r=-0.618, P= 0.018, respectively)Conclusion:In early and mild pulmonary hypertension, the basal torsion of left ventricular was decreased. In severe pulmonary hypertension, all the basal, apical and globle torsions were injured. STI can be used for early assessment of left ventricular torsional function in patients with PH. |
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