Purpose To explore the cardioprotective effect of cang-ai volatile oil(CAVO)on rats with cardiac function impairment model under low-pressure and low-oxygen environment in Tibet Plateau based on 7.0T cardiovascular magnetic resonance(CMR)imaging.Materials and Methods Forty SD rats were randomly divided into the normal group,the high altitude model group,the CAVO-treated group and the rhodiola rosea-treated group,with 10 rats in each group.Except for the normal group,the rats in other groups were transferred from the plain(500 m above sea level)to the Tibet Plateau(4 250 m above sea level)for two months,and then administered with the corresponding drugs by gavage for 14 d.The left ventricle function was measured by using a 7.0T high-field strength CMR and myocardial strain was analysed by using tissue tracing technique.HE staining was used to observe the morphology of cardiomyocytes,Masson staining to observe interstitial fibrosis,wheat germ agglutinin staining to observe cardiomyocyte hypertrophy,and transmission electron microscopy to observe the morphological changes of mitochondria in each group.Serum levels of creatine kinase,creatine kinase isoenzyme,lactate dehydrogenase,cardiac troponin T,superoxide dismutase,malondialdehyde and glutathione peroxidase were detected.Intracellular reactive oxygen species levels were detected using flow cytometry.Results The left ventricular ejection fraction of rats in the CAVO-treated group was higher than that of the high altitude model group[(66.61±1.38)％vs.(60.94±3.21)％;t=3.969,P=0.032];meanwhile,the global circumferential strain of the left ventricle in the CAVO-treated group was higher than that of the high altitude model group(-25.68±1.30 vs.-22.84±1.17;t=3.967,P=0.003).HE,Masson and wheat germ agglutinin staining showed hypertrophy and necrosis as well as interstitial fibrosis and ultrastructural disruption of cardiomyocytes in the high altitude model group,which improved after CAVO treatment.The level of cardiac troponin T in the serum of rats with CAVO treatment group was significantly decreased compared with that of the high altitude model group[(314.03±20.05)pg/ml vs.(518.30±18.13)pg/ml;1=13.090,P=0.001].Conclusion CAVO treatment can reduce cardiac injury caused by low-pressure hypoxia in high altitude,and its effect can be detected dynamically and non-invasively by 7.0T high-field strength CMR.