关于缺血心肌组织多普勒频谱识别的探讨

【目的】确认缺血心肌组织多普勒 (DTI)频谱各速度波及缺血前后的变化。【方法】开胸犬 13条 ,于冠脉左旋支的分支结扎前、后记录乳头肌水平左室后壁短轴方向的DTI运动频谱 ,结合同步记录的心电图、心内压力曲线 (P ,dP/dt)及心音图辨认DTI频谱的各速度波 ,比较冠脉结扎前、后DTI频谱的变化 ;观察19例心肌梗死患者 ,记录左室壁及二尖瓣环DTI频谱和组织速度图 (TVI) ,结合心电图辨认各速度波。【结果】正常开胸犬左室后壁短轴方向运动速度波 ,等容收缩期以正向为主 (IVC1) ,急性缺血时出现明显的反向运动波 (IVC2 )并可延至射血期 ,冠脉结扎前、后IVC1和IVC2 峰值均发生显著变化 (16 .6 0± 4 .11)cm/s对(4 .6 0± 5 .38)cm/s和 (5 .97± 6 .2 5 )cm/s对 (19.5 7± 3.5 8)cm/s,P <0 .0 1];冠脉结扎后射血期S波峰值显著降低 (11.30± 1.5 8)cm/s对 (7.16± 1.80 )cm/s ,P <0 .0 1],舒张早期E波反向或双向变化 (10 .86±3.32 )cm/s对 (- 10 .72± 6 .36 )cm/s,P <0 .0 1],左房收缩期A波峰值速度降低 (11.0 8± 3.35 )cm/s对 (6 .71± 4 .81)cm/s ,P <0 .0 5 ]。临床观察心肌梗死患者亦发现类似犬急性缺血心肌DTI频谱的变化。【结论】在心肌严重缺血或梗死的情况下 ,DTI频谱等容收缩期出现反向 ,S波峰值

Exploration of Ischemic Myocardia by Doppler Tissue Imaging Spectra

To identify the various velocity waves of ischemic myocardia by Doppler tissue imaging (DTI) spectra and their alterations before and after ischemia.Left ventricular (LV) wall motion velocity patterns at the mid-wall portion of the middle of LV posterior walls along the short-axis direction in 13 open-chest dogs were recorded with DTI spectra before and after ligation of branches from left coronary arteries. Their LV pressure (P) curves, first derivative (dP/dt) curves, electrocardiogram (ECG) and phonocardiogram (PCG) were recorded simultaneously. Compared with ECG, PCG, P curves, and dP/dt curves, the various velocity waves of DTI spectra in ischemic myocardia and their alterations could be identified. The motions of LV walls and mitral annuli in 19 patients with myocardial infarction were observed by DTI spectra and tissue velocity imaging (TVI) curves. The velocity waves of DTI spectra and TVI curves were recognized in combination with ECG.The normal LV posterior wall motions in open-chest dogs were mainly positive (IVC 1) during isovolumic contraction, while their acutely ischemic walls motioned negatively(IVC 2) and these negative motions could prolong into ejecting phase. Before and after the occlusion of coronary arteries, acute ischemia resulted in significant reduction of peak IVC 1, wave peak S of blood ejection period and wave peak A of left auricle contraction.but the velocity of peak IVC 2 increased distinctly. The peak E during early period of diastole became negative or bi-directional. Similar alterations of DTI spectra were found in the patients with myocardial infarction.Conclusion]Negative motion of DTI spectra during isovolumic contraction, significant decline of peak S velocity and a negative or bi-directional peak E can appear in seriously ischemic or infarcted myocardia. Different conclusions or mistakes will be drawn from results of DTI spectra analysis if cardiographic phase is not identified in combination with ECG changes.