Clinical Studies Of Left Ventricular Short-axis Views Systolic Function Using Two-dimensional Speckle Tracking Imaging

Background and ObjectivesEchocardiogram has clinical significance to assess myocardial function. It is subjective to assess ventricular function by observing ventricular wall motion. Results have major variability. TDI-based strain and strain rate imaging are angle dependent, it can only be used to assess the longitudinal strain.2D-STI is a new tool for quantifying regional ventricular function. Previous studies indicated that STI results consist with sonomicrometry and magnetic resonance imaging (MRI) for systolic strain. This study can not only analyze the myocardial strain to observe the influence of extrinsic and intrinsic factor-induced damage using STI in patients withprimary hypertension (HTN), secondary hypertension (all patients are CRF) and thoracic radiotherapy, but also approach the value of STI in assessment of primary hypertension and symptomatic hypertension and thoracic radiotherapy-induced myocardial damage early, hoping to find a effectively noninvasive tool for the assessment of regional myocardial function.Methods1. Hypertension 36 patients with CRF,35 with HTN and 30 healthy subjects were enrolled.2.Thoracic radiotherapy The patients were divided into three groups(46 patients in groups A,B,C respectively):group A:before the radiation treatment(control group); group B:radiotherapy time was 2.5～3 weeks, radiotherapy dose was 26～30Gy; group C:radiotherapy time was 5～6 weeks, radiotherapy dose was 50～60Gy.Using S5～1 probe of Philips IE33,Dynamic images of two continuous cardiac cycles were recorded and saved from the left ventricular short-axis views at the levels of mitral annulus and papillary muscle. Images were transferred to Qlab7.1 work station for offline strain analysis. The peak systolic circumferential strain (CS) and radial strain (RS) were measured in the left ventricular short-axis views and the general average of two continuous cardiac cycles was selected. At the same time, the indexes of cardiac structure(LVIDs, LVIDd, IVSd, LVPWd and LVM) and cardiac function (EF%)were examined in three groups.Results1. Normal group The peak systolic RS of the left ventricular short-axis views had statistical significance (P<0.05).The RS was highest at the level of papillary muscle view. The RS had no statistical significance in different segments of the same level, (P>0.05). The peak systolic CS had statistical significance in the same segment on the different left ventricular short-axis views (P<0.05). The CS of anterior septal and inferior wall was higher than other walls at the same level. The CS of lateral wall and posterior wall was lower than other walls at the same level, having statistical significance (P<0.05)2. CRF group The peak systolic RS of the left ventricular short-axis views at the levels of mitral annulus and papillary muscle in the different segments was significantly lower than normal group (P<0.01) and lower than HTN group (P< 0.05). The peak systolic CS of anterior septal and inferior wall was significantly lower than normal group (P<0.01). The peak systolic CS of lateral wall, posterior wall, anterior wall, posterior septal was lower than normal group and HTN group (P <0.05)3. HTN group The peak systolic RS of the left ventricular short-axis views at the levels of mitral annulus and papillary muscle in the different segments was lower than normal group (P<0.05). The peak systolic CS of anterior septal and inferior wall was significantly lower than normal group (P<0.05).The peak systolic CS of lateral wall, posterior wall, anterior wall, posterior septal had no significant difference (P>0.05) compared with normal group (P<0.05)4. RS and CS of group C in anterior wall, anterior septal and posterior wall were significantly lower than those in group A (P＜0.01); RS and CS of group C in anterior wall, anterior septal and posterior wall were lower than those in group B (P<0.05);RS and CS of group B in anterior wall, anterior septal and posterior wall compared with those in group A, had no significantly difference (P>0.05)5. RS and CS of left lateral wall, posterior septal and inferior wall in all groups had no significantly difference (P>0.05)Conclusion1. The peak systolic RS and CS of CRF group were lower than HTN group. The EF of CRF group had no statistical significance than HTN group. STI can detect the change of left ventricular systolic function earlier than general ultrasound.2. STI can reflect that the left ventricular short-axis views systolic function of CRF group damages larger than HTN group and quantitatively detect the alteration of the systolic function of the left ventricular short-axis views.3. RS and CS of radiated muscle tissue after the thoracic radiation treatment were lower than before the thoracic radiation treatment at the level of radiotherapy time and radiotherapy dose. STI can detect early thoracic radiotherapy-induced myocardial damage.4. STI can reflect extrinsic and intrinsic factor-induced myocardial damage early,so it is a effectively noninvasive tool.