[Relationship of high altitude de-adaptation with acute high altitude response and cardiac function].

Objective: To assess the relationship of high altitude de-adaptation response (HADAR) with acute high altitude response (AHAR) and cardiac function.

Methods: Ninety-six military personnel of rapid entering into high altitude (3 700 to 4 800 m) with strong physical work were analyzed, all subjects were male, aged 18 - 35 years. According to the symptomatic scores of AHAR were divided into 3 groups: sever AHAR (group A, 24), mild to moderate AHAR (group B, 47) and non-AHAR (group C, 25) at high altitude. According to the symptomatic scores of HADAR were divided into 3 groups: severe HADAR (group E, 19), mild to moderate HADAR (group F, 40) and non-HADAR (group G, 37) after return to lower altitude (1 500 m). Mean pulmonary arterial pressure (mPAP), right ventricular internal dimension (RVID), outflow tract of right ventricle (RVOT), left ventricular internal dimension (LVID), left ventricular ejection fraction (LVEF), cardiac muscle work index (Tei index), creatine kinase isoenzymes-MB (CK-MB), lactic dehydrogenase isoenzyme-1 (LDH-1) were measured at high altitude stayed 50 days and after return to lower altitude 12 h, 15 d, and 30 d. Fifty healthy volunteers (group D) at 1 500 m altitude served as control.

Results: Level of mPAP, RVID, RVOT, RVID/LVID ratio, Tei index, CK-MB,and LDH-1 were higher, and LVEF was lower in group A than those in group B, C and D, there were significant differences between group B and C, C and D (all P < 0.01). AHAR scores were positively correlated with HADAR scores (r = 0.863, P < 0.01). Twelve hours after return to lower altitude, level of mPAP, RVID, RVOT, RVI/LVID ratio, Tei index, CK-MB, and LDH-1 were higher, and LVEF was lower in group E than those in group F, G and D, there were significant differences between group F and G, G and D (all P < 0.01). Fifteen days after return to lower altitude, level of mPAP, RVID, RVOT, RVID/LVID ratio were higher in group E than those in group F, G, and D, there were significant differences between group F and G, and D (P < 0.01 or P < 0.05), there were no significant differences between group G and D (all P > 0.05), LVEF, Tei index, CK-MB, LDH-1 showed no significant differences among groups (all P > 0.05). Thirty days after return to lower altitude, these parameters in group E, F, and G showed no significantly differences compared with those of group D (all P > 0.05).

Conclusion: The severity of HADAR is associated with severity of AHAR and cardiac injury, the more serious of AHAR and cardiac injury at high altitude, the more serious of HADAR and cardiac injury after return to lower altitude, the more long of restore of right cardiac morphologic injury.