Association between baseline blood pressure variability and cardiac mechanics and electrophysiology after acute exposure to high altitude.

Ascending to high altitude (HA) for leisure, work, or sports is becoming increasingly popular. However, exposure to HA is widely considered a form of cardiac stress, resulting in various changes to cardiac mechanical and electrophysiological functions in individuals. The factors associated with cardiac function following HA exposure remain unclear. This retrospective study, with a significant sample size, aims to document the effects of HA on the mechanical and electrophysiological parameters of the heart. We also sought to investigate the risk factors associated with changes in these parameters after HA exposure. A total of 336 healthy young subjects who experienced an acute exposure to HA (3700 m) from a low altitude (LA) (500 m) within 3 h by airplane were included. Physiological data collection, 24-hour ambulatory blood pressure monitoring, electrocardiogram, and echocardiography examinations were conducted at both LA and upon their arrival at HA. Correlation analysis, logistic regression and ROC curve analysis were performed to analyze the relationship between baseline cardiovascular indices and cardiac function change. The results indicated a significant increase in cardiac twist mechanics and a marked prolongation of ventricular repolarization (VR) following rapid ascent to the plateau. Multivariate regression analysis demonstrated that baseline blood pressure variability was associated with cardiac mechanical function (parameters of left ventricular systolic force and function level) and electrophysiological function (parameters of VR level) after HA exposure. It could also serve as a potential predictor with good predictive value for the variations in these parameters after reaching HA. These findings may provide valuable insights into the protection of cardiac function and cardiac adaptation during altitude exposure.