Hirata K, Ban T, Jinnouchi Y, Kubo S
Department of Cardiovascular Surgery, Kyoto University Faculty of Medicine, Japan.
Am J Cardiol. 1991 Dec 15;68(17):1692-7. doi: 10.1016/0002-9149(91)90331-e.
To understand the effects of high-altitude hypoxia on cardiac function and the change in cardiac function during high-altitude acclimatization, precise studies were first performed at greater than 5,000 m of altitude in Himalaya by 2-dimensional echocardiography. In addition to examining well-known indexes of cardiac function, the centerline method was used to assess regional wall motion, which has not been examined under conditions of high-altitude hypoxia. The subjects were 11 climbing members (aged 21 to 43 years) of the Kyoto University Medical Research Expedition of Xixabangma (8,027 m) in 1990. Examinations were performed at sea level, at the base camp (5,020 m), and twice at the advanced base camp (5,650 m). Heart rate, left ventricular (LV) end-diastolic volume, cardiac output, mean rate of circumferential fiber shortening, ejection fraction, % fractional shortening, and regional LV wall motion were measured. At high altitude, heart rate increased to 136% of the sea level value, but gradually decreased in the degree of increment at the early and late advanced base camp measurements. LV end-diastolic volume decreased significantly by 70%. At base camp there were significant increases in ejection fraction, mean rate of circumferential fiber shortening, and % fractional shortening, which showed little change during the long-term stay at high altitude. Regional wall motion at high altitude (measured by the center-line method) decreased at the septal wall and increased at the posterolateral wall. These results demonstrate that: (1) LV cardiac performance at high altitude is enhanced significantly in spite of reduced preload. After good acclimatization, cardiac performance remains augmented, but there is a tendency to decrease the degree of augmentation. (2) In regional LV wall motion, septal wall motion is impaired, but LV posterolateral wall motion shows a compensatory increase.
为了解高海拔低氧对心脏功能的影响以及高海拔习服过程中心脏功能的变化，最初在喜马拉雅山脉海拔超过5000米处采用二维超声心动图进行了精确研究。除了检查众所周知的心脏功能指标外，还使用中心线法评估局部室壁运动，而这在高海拔低氧条件下尚未得到研究。研究对象为1990年京都大学医学研究队攀登希夏邦马峰（8027米）的11名登山队员（年龄21至43岁）。在海平面、大本营（5020米）以及前进营地（5650米）进行了两次检查。测量了心率、左心室舒张末期容积、心输出量、平均圆周纤维缩短率、射血分数、缩短分数百分比以及左心室局部室壁运动。在高海拔地区，心率增加至海平面值的136%，但在前进营地早期和晚期测量时，增加程度逐渐降低。左心室舒张末期容积显著减少70%。在大本营，射血分数、平均圆周纤维缩短率和缩短分数百分比显著增加，在高海拔长期停留期间变化不大。高海拔地区的局部室壁运动（通过中心线法测量）在室间隔壁减少，在后外侧壁增加。这些结果表明：（1）尽管前负荷降低，但高海拔地区左心室心脏功能显著增强。良好习服后，心脏功能仍保持增强，但增强程度有降低趋势。（2）在左心室局部室壁运动方面，室间隔壁运动受损，但左心室后外侧壁运动出现代偿性增加。
