A Systematic Review of Electrocardiographic Changes in Populations Temporarily Ascending to High Altitudes

High altitudes can cause hypobaric hypoxia, altering human physiology and the corresponding electrocardiogram (ECG). As part of the Altitude Nondifferentiated ECG Study (ANDES), this paper reviews ECG changes in subjects ascending to high altitudes. This review was conducted following PRISMA guidelines. PubMed, EMBASE, OVID Medline, and Web of Science were searched. 19 studies were ultimately included. Notable ECG changes at high altitudes include T wave inversion in the precordial leads and rightward QRS axis deviation in leads I, II and aVF. Less common findings were increases in P wave amplitude, QRS amplitude, and QTc interval. These ECG deviations typically self-resolved within 2-6 weeks following return to sea level. Consideration must be taken when interpreting ECG changes in individuals during ascent to, at, or upon return from high altitudes. Further large-scale studies are needed to elucidate temporal and altitude-dependent ECG patterns and establish reference standards for clinicians.