Association between heart rate variability and ECG changes in on-duty prehospital physicians

Area of Science:

• Emergency medicine
• Cardiology
• Occupational health

Background:

• Prehospital emergency physicians face significant physical and psychological stress.
• Previous studies noted electrocardiogram (ECG) changes, including heart rate variability (HRV) and ST-T segment alterations, linked to stress.
• The direct association between HRV and ST-T segment changes in this high-stress environment remained unclear.

Purpose of the Study:

• To investigate the association between HRV metrics and the risk of ST-T abnormalities in prehospital emergency physicians.
• To analyze HRV variations during different phases of emergency medical missions.
• To determine if HRV can serve as a reliable indicator for stress-related cardiac changes.

Main Methods:

• Retrospective analysis of data from a prospective trial involving 20 prehospital emergency physicians.
• Analysis of HRV metrics, including standard deviation of normal-to-normal (SDNN) and root mean square of successive differences (RMSSD) intervals.
• Evaluation of ST-T abnormalities on a 5-minute and per-mission basis, correlating these with HRV parameters.

Main Results:

• SDNN showed a positive association with ST-T abnormalities (OR: 1.04), while RMSSD demonstrated a negative association (OR: 0.73) per mission.
• pNN50 metric was not significantly associated with ST-T abnormalities.
• HRV was significantly lower during patient care and transport compared to alarm and en-route phases.

Conclusions:

• No reliable correlation was found between HRV values and ST-T segment changes in prehospital emergency physicians during missions.
• The findings question the sufficiency of HRV alone in detecting ischemia-like changes during stressful prehospital events.
• Further research is needed to understand the complex interplay between stress and cardiac markers in this population.