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High Resolution ECG for Evaluation of Heart Function During Exposure to Subacute Hypobaric HypoxiaHigh altitude climbing presents a wide spectrum of health risks, including exposure to hypobaric hypoxia. Risks are also typically exacerbated by the difficulty in appropriately monitoring for early signs of organ dysfunction in remote areas. We investigated whether high resolution advanced ECG analysis might be helpful as a non-invasive and easy-to-use tool (e.g., instead of Doppler echocardiography) for evaluating early signs of heart overload in hypobaric hypoxia. Nine non-acclimatized healthy trained alpine rescuers (age 43.7 plus or minus 7.3 years) climbed in four days to the altitude of 4,200 m on Mount Ararat. Five-minute high-resolution 12-lead electrocardiograms (ECGs) were recorded (Cardiosoft) in each subject at rest in the supine position on different days but at the same time of day at four different altitudes: 400 m (reference altitude), 1,700 m, 3,200 m and 4,200 m. Changes in conventional and advanced resting ECG parameters, including in beat-to-beat QT and RR variability, waveform complexity, signal-averaged, high-frequency and spatial/spatiotemporal ECG was estimated by calculation of the regression coefficients in independent linear regression models. A p-value of less than 0.05 was adopted as statistically significant. As expected, the RR interval and its variability both decreased with increasing altitude, with trends k = -96 ms/1000 m with p = 0.000 and k = -9 ms/1000 m with p = 0.001, respectively. Significant changes were found in P-wave amplitude, which nearly doubled from the lowest to the highest altitude (k = 41.6 microvolt/1000 m with p = 0.000), and nearly significant changes in P-wave duration (k = 2.9 ms/1000 m with p = 0.059). Changes were less significant or non-significant in other studied parameters including those of waveform complexity, signal-averaged, high-frequency and spatial/spatiotemporal ECG. High resolution ECG analysis, particularly of the P wave, shows promise as a tool for monitoring early changes in heart function due to exposure to high altitude.
Document ID
20100008455
Document Type
Conference Paper
Authors
Zupet, Petra (Ljubljana Univ. Ljubljana, Slovenia)
Finderle, Zarko (Ljubljana Univ. Ljubljana, Slovenia)
Schlegel, Todd T. (NASA Johnson Space Center Houston, TX, United States)
Princi, Tanja (Trieste Univ. Italy)
Starc, Vito (Ljubljana Univ. Ljubljana, Slovenia)
Date Acquired
August 25, 2013
Publication Date
January 1, 2010
Subject Category
Aerospace Medicine
Report/Patent Number
JSC-CN-19924
Meeting Information
37th International Congress on Electrocardiology(Lund)
Distribution Limits
Public
Copyright
Other