T wave changes in humans and dogs during experimental dives

Area of Science:

• Physiology
• Cardiology
• Hyperbaric Medicine

Background:

• Understanding the physiological effects of inert gas narcosis and high-pressure environments is crucial for deep-sea exploration and diving safety.
• Electrocardiogram (ECG) analysis provides valuable insights into cardiac function under various physiological stresses.

Purpose of the Study:

• To investigate the impact of elevated hydrostatic pressure and different inert gas mixtures on cardiac function, specifically heart rate and ECG parameters.
• To determine if gas density influences cardiac electrical activity during hyperbaric exposures.

Main Methods:

• Conducted ECG analysis on three human divers at 21 and 23.5 ATA breathing H2/He mixtures (COMEX HYDRA IX).
• Exposed five dogs to 91 ATA of He-O2 or He-N2-O2 mixtures.
• Monitored resting heart rate, respiratory fluctuation, and T wave amplitude and configuration.

Main Results:

• Elevated pressure of various inert gases did not alter resting heart rate or its respiratory fluctuation in humans or dogs.
• T wave amplitude increased proportionally to gas density in three human divers and four of five dogs.
• Observed changes in peak T wave configurations in dog experiments, not attributable to positional vector shifts.

Conclusions:

• High-pressure inert gas environments do not significantly affect resting heart rate or its variability.
• Increased gas density under hyperbaric conditions is associated with augmented T wave amplitude in ECGs.
• Further research is needed to elucidate the mechanisms behind T wave changes in response to gas density.