Department of Cardiovascular Diseases, Mayo Clinic, Rochester, Scottsdale, MN, 55905, USA.
School of Allied Health Sciences, Griffith University, Gold Coast, Australia.
Eur J Appl Physiol. 2020 Apr;120(4):799-809. doi: 10.1007/s00421-020-04319-3. Epub 2020 Feb 19.
High-altitude ascent induces left (LV) and right (RV) ventricular adaptations secondary to hypoxia-related hemodynamic and myocardial alterations. Since cardiopulmonary decrements observed with aging (e.g., decreased LV compliance and increased pulmonary vascular resistance) may limit cardiac plasticity, this study examined myocardial adaptability throughout an 11 day sojourn to 5893 m in young and older-aged trekkers.
Echocardiography was performed on 14 young (8 men; 32 ± 5 years) and 13 older-aged (8 men; 59 ± 5 years) subjects on non-trekking days (Day 0: 880 m; Day 3: 3100 m; Day 8: 4800 m; Day 12/post-climb: 880 m). RV systolic pressure (mmHg) was systematically higher in older-aged subjects (p < 0.01) with similar progressive increases observed during ascent for young and older subjects, respectively (Day 0: 18 ± 1 vs 20 ± 2; Day 3: 25 ± 2 vs 29 ± 3; Day 8: 30 ± 2 vs 35 ± 2). Estimates of LV filling pressure (E/E') were systematically higher in older subjects (p < 0.01) with similar progressive decreases observed during ascent for young and older-aged subjects, respectively (Day 0: 5.6 ± 0.3 vs 6.7 ± 0.5; Day 3: 5.1 ± 0.2 vs 6.1 ± 0.3; Day 8: 4.7 ± 0.3 vs 5.4 ± 0.3). Overall, RV end-diastolic and end-systolic area increased at altitude (p < 0.01), while LV end-diastolic and end-systolic volume decreased (p < 0.01). However, all RV and LV morphological measures were similar on Day 3 and Day 8 (p > 0.05), and returned to baseline post-climb (p > 0.05). Excluding mild LV dilatation in some older-aged trekkers on Day 8/Day 12 (p < 0.01), altitude-induced morphological and functional adaptations were similar for all trekkers (p > 0.05).
Altitude-induced myocardial adaptations are chamber specific, secondary to RV and LV hemodynamic alterations. Despite progressive hemodynamic alterations during ascent, morphological and functional cardiac perturbations plateaued, suggesting rapid myocardial adaptation which was mostly comparable in young and older-aged individuals.
高海拔上升会导致左心室（LV）和右心室（RV）适应，这是由于缺氧相关的血液动力学和心肌改变引起的。由于衰老时观察到的心肺功能下降（例如，LV顺应性降低和肺血管阻力增加）可能会限制心脏的可塑性，因此本研究在年轻和老年徒步旅行者中进行了为期 11 天的海拔 5893 米的攀登，以检查心肌的适应性。
在非攀登日（第 0 天：880 米；第 3 天：3100 米；第 8 天：4800 米；第 12 天/攀登后：880 米），对 14 名年轻（8 名男性；32±5 岁）和 13 名老年（8 名男性；59±5 岁）受试者进行了超声心动图检查。RV 收缩压（mmHg）在老年受试者中明显更高（p<0.01），而年轻和老年受试者的 RV 收缩压在上升过程中分别出现相似的递增（第 0 天：18±1 与 20±2；第 3 天：25±2 与 29±3；第 8 天：30±2 与 35±2）。老年受试者的 LV 充盈压（E/E'）估计值明显更高（p<0.01），而年轻和老年受试者的 LV 充盈压在上升过程中分别出现相似的递减（第 0 天：5.6±0.3 与 6.7±0.5；第 3 天：5.1±0.2 与 6.1±0.3；第 8 天：4.7±0.3 与 5.4±0.3）。总体而言，RV 舒张末期和收缩末期面积在高原上升（p<0.01），而 LV 舒张末期和收缩末期容积下降（p<0.01）。然而，所有 RV 和 LV 形态学测量在第 3 天和第 8 天都相似（p>0.05），并且在攀登后恢复到基线（p>0.05）。除了一些老年徒步旅行者在第 8 天/第 12 天出现轻度 LV 扩张（p<0.01）外，所有徒步旅行者的海拔诱导的形态和功能适应性都相似（p>0.05）。
高原诱导的心肌适应性是心室特异性的，是 RV 和 LV 血液动力学改变的结果。尽管上升过程中血液动力学逐渐改变，但形态和功能的心脏紊乱达到了稳定状态，这表明了快速的心肌适应，这种适应在年轻和老年个体中基本相似。
