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Acceleration-induced atrioventricular dissociation: hemodynamic consequences
Aviation, Space, and Environmental Medicine
|May 1, 1982
Summary
Physiologically enhanced vagal tone can cause atrioventricular (AV) dissociation during high Gz stress, impacting cardiac output and vision. Fitness programs for pilots should consider this risk.
Area of Science:
- Cardiovascular Physiology
- Aerospace Medicine
Background:
- Atrial systole contributes to cardiac output, especially under stress.
- Compensatory mechanisms can mask atrial dysfunction at rest.
Observation:
- A healthy male pilot experienced atrioventricular (AV) dissociation during +Gz stress.
- Vision was compromised at higher Gz levels due to this condition.
Findings:
- High +Gz stress likely caused a 30 torr drop in arterial pressure, leading to loss of atrial function.
- Enhanced vagal tone in an avid jogger was the suspected cause of AV dissociation.
Implications:
- Physical fitness programs for high-performance aircraft pilots require careful consideration of potential cardiovascular risks.
- Maintaining atrial function is critical for optimal cardiac output during maximal stress in aviators.