高原人体左心室舒张功能和顺应性的改变

应用同步描记心电图、心音图、颈动脉搏动图和心尖搏动图以测定高原人体的左心室舒张功能和顺应性。在4个不同海拔高度进行实验,即76m(海平对照)、2161m、3270m和4179m,每一高度40名健康男性青年,高原3组世居、移居各20名。结果显示:随着海拔增高,主动舒张时间指数(TRTI)有减小趋势,RF波相对振幅(F/H)逐渐降低,A波相对振幅(A/D)则渐趋增大,3270m以上增大明显(p<0.05),舒张振幅时间指数(DATI)逐渐降低,3270m以上差异极显著(p<0.001)。高原世居与移居者相比,在海拔4179m出现明显差别,移居组TRTI、DATI、F/H较低而A/D较高(D<0.05)。测定射血前期与左室射血时间比值(PEP/LVET)、射血分数(EF)及左室周径纤维平均缩短速度(mVcf)3项指标作对照,显示在此高度左室收缩功能仍能保持。高原慢性心肌缺氧可能是导致左室舒张功能和顺应性轻度降低的原因。

THE LEFT VENTRICULAR DIASTOLIC FUNCTION AND COMPLIANCE IN HEALTHY RESIDENTS AT HIGH ALTITUDE

In order to study the left ventricular (LV) diastolic events at high altitude, ECG, PCG, CPT and apexcardiography (ACG) were simultaneously recorded in 4 groups of 40 healthy young male residents each at different altitudes, i.e. 76, 2 261, 3 270, and 4 179m above sea level. At high altitudes, the experimental subjects were divided into two groups, 20 natives and 20 immigrants who have lived at high altitude over 10 years.The results showed that TRTI had tendency of decrease and A / H had tendency of increase with increasing altitude, but no statistical difference (p>0.05). F/ H decreased with increasing altitude, showing statistical significance at 4 179m (p<0.05). A/D increased with increasing altitude, showing statistical significance at 3270m (p<0.05) and high significance at 4179m (p<0.01). DATI decreased with increasing altitude and the difference from the sea level controls was very significant (p< 0.001) at altitudes over 3 270m. At 4 179m, decrease in TRTI, DATI, and F/ H and increase in A/ D were more significant in the immigrants than in the natives (p<0.05). PEP / LVET increased with increasing altitude, while EF and mVcf showed no significant change with change of altitude. It seems that increase in PEP / LVET is related to decrease preload of LV, so the LV systolic function can be maintained. It is concluded that at high altitude, the chronic myocardial hypoxia may be responsible for slight decrease in LV relaxation and compliance.