脉冲多普勒组织成像技术评价左室舒张功能与前负荷的依赖关系

Is Doppler tissue imaging dependent on preload in evaluating left ventricular diastolic function?

目的研究脉冲多普勒组织成像(PW-DTI)测量的二尖瓣环速度指标是否受前负荷改变的影响。方法选取2型糖尿病(DM)77例,正常对照43例,肥胖症(0B)18例,分别采取二尖瓣环运动多普勒频谱和二尖瓣血流多普勒频谱(MPWD)检测基础状态下(阶段1)受试者的左室舒张功能。测量指标包括:二尖瓣环舒张早、晚期最大运动速度(Em、Am)及其比值(Em/Am)、二尖瓣血流舒张早、晚期最大速度(E、A)及其比值(E/A)、等容舒张时间(IVRT)。受试者舌下含服5.0mg硝酸甘油,减低左室前后负荷后(阶段2)重复上述测量。结果与基础状态比较,左室前负荷减低后3组心率均加快、IVRT均延长,DM组Em及Em/Am、E及E/A减低,Am和A不变;OB组Em、E及E/A减低,Am、Em/Am和A不变;对照组Em及Em/Am、E及E/A减低,Am增加,A不变。3组Sm、EF、FS、SV和HR2个阶段均在正常范围内。结论PW-DTI舒张功能指标的测定随着前负荷的变化而变化。

Objective To determine whether Doppler tissue flow velocities are influenced by the alteration of preload. Methods In this study, 77 type-2 diabetic mellitus (DM) patients, 43 healthy volunteers and 18 obesity (OB) patients were selected to measure the early and late maximal diastolic movement velocity of the mitral ring (Em,Am) and their ratio (Em/Am), maximal blood velocity at early and late diastolic phase of the bicuspidal value (E,A)and their ratio (E/A), and isovolumetric relaxation time(IVRT). The measurement was repeated after decreasing the pre- and after-load of the left ventricular by taking nitroglycerin sublingually.Results After decreasing preload, the heart rate increased and IVRT prolonged in all groups. In group DM, Em, Em/Am ratio, E and E/A ratio decreased. In group OB, Em, E and E/A decreased. In group control, Em/Am ratio, E and E/A decreased and Am increased. Conclusions In contrast to standard tranmitral Doppler filling indices, Doppler tissue early diastolic velocities are significantly affected by physiological maneuvers that alter preload. Thus PW-DTI is preload dependent in assessment of left ventricular diastolic function.