高原重体力劳动对部队官兵心脏结构和功能的影响及返回低海拔后恢复的变化

Effect of strenuous physical activitat at high-altitude on cardiac structure and function and changes after return to lower altitude

目的:观察高原低氧重体力劳动对部队官兵心脏结构和功能的影响及返回低海拔后恢复变化情况。方法:选择由低海拔(1 500 m)快速进入高原(3 700 m)并从事重体力劳动的男性官兵96名,年龄18～35岁。根据急性高原反应(AHAR)症状评分,分为无AHAR组(n=25)、轻中度AHAR组(n=47)和重度AHAR组(n=24)。在该高度逗留50 d后下撤前及返回低海拔(1 500 m)后12 h、15 d和30 d用超声心动图测定平均肺动脉压(mPAP)、右心室内径(RVID)、右心室流出道(RVOT)、左心室内径(LVID)、心肌做功指数(Tei指数)、左心室射血分数(LVEF),同时选择低海拔(1 500 m)地区的50名健康官兵作为对照组。结果:在高原,无AHAR组mPAP、RVID、RVOT、RVID/LVID比值、Tei指数显著高于对照组,而LVEF显著低于对照组(均P<0.01);且随AHAR加重,各项指标进一步变化,轻中度组与重度组之间两两比较差异均有统计学意义(均P<0.01)。高原50 d时,mPAP与RVID、RVOT、RVID/LVID比值和Tei指数呈显著正相关(分别r=0.613、0.647、0.585、647,均P<0.01),与LVEF显著负相关(r=-0.620,均P<0.01)。与对照组比较,96名官兵在高原地区50 d时,mPAP、RVID、RVOT、RVID/LVID和Tei指数显著升高,LVEF显著降低(均P<0.01),返回低海拔12 h、15 d时mPAP、RVID、RVOT、RVID/LVID比值和Tei指数显著降低,LVEF显著升高(均P<0.01),15 d时mPAP、Tei指数、LVEF与对照组比较均无显著性差异,30 d时RVID、RVOT、RVID/LVID进一步降低,与对照组比较均P>0.05。结论:平原部队快速进入高原低氧环境并从事重体力劳动时,AHAR越重,右心室增大和左心室功能降低越明显,返回低海拔后12 h有显著改善,15 d左心功能恢复正常,30 d右心室增大恢复正常。

AIM ： To assess the effect of high-altitude strenuous physical activity on cardiac structure and function and to explore the changes after return to a lower altitude. METHODS： Ninety-six officers and soldiers leaving low-attitude areas （ 1 500 m） and moving directly to high-altitude areas （ 3 700 m） to undertake strenuous physical activities were enrolled in the study. The subjects （all male, aged 18 -35 years） were divided into three groups according to the symptomatic scores of acute high-altitude reaction （AHAR）： non-AHAR （group B, n= 25）, mild to moderate AHAR （group C, n =47） and severe AHAR （group D, n =24）. Mean pulmonary arterial pressure （mPAP）, right ventricular internal dimension （RVID） , outflow tract of right ventricle （RVOT） , left ventricular internal dimension （LVID） , cardiac muscle work index （Tei index）, and left ventricular ejection fraction （LVEF） were measured by echo-cardiograph after 50 days at high altitude area and 12 h, 15 days and 30 days after return to lower altitude （1 500 m）. Fifty healthy volunteers （group A） at 1 500 m altitude served as control. RESULTS： Levels of mPAP, RVID, RVOT, RVID/LVID ratio and Tei index were higher and LVEF was lower in group B than those in group A （ all P 〈 O. O1 ）. The value of all the parameters further changed with increasing severity of AHAR, and significant differences were found between groups C and D （all P 〈 0. 01 ）. After 50 days at an altitude of 3700 m, mPAP was positively correlated with RVID, RVOT, RVID/LVID ratio and Tel index （r =0. 613,0. 647, 0. 585, 0. 647, respectively, all P 〈0. O1 ）, but negatively correlated with LVEF （r = - 0. 620, P 〈 0. 01 ）. Compared with those in group A, levels of mPAP, RVID, RVOT, RVID/LVID ratio and Tei index significantly increased, whereas LVEF significantly decreased in the 96 officers and soldiers after 50 days at an altitude of 3 700 m （ all P 〈 0. O1 ）. Levels of mPAP, RVID, RVOT, RVID/LVID ratio and Tei index significantly decreased but LVEF significantly increased 12 h and 15 days after return to lower altitude, with significant difference between 12 h and 15 days （both P 〈 0. 01 ）. The levels of mPAP, Tei index and LVEF 15 days after return to lower altitude showed no signifi- cant difference compared with those in group A （ all P 〉 0.05 ） and the levels of RVID, RVOT and RVID/LVID ratio 30 days after return to a lower altitude showed no significant difference compared with those of group A （all P 〉 0. 05）. CONCLUSION： In the case of strenuous physical work following direct migration from a lower altitude （1 500 m） to a higher altitude （3 700 m）, the more serious AHAR becomes, the more obvious right ventricular enlargement and decrease of left ventrieular functions would be. These changes would be alleviated 12 h after returning to a lower altitude. Left ventrieular function would be restored to normal 15 days after returning to lower altitude 30 days after returning to lower altitude.