Coronary flow and mental stress. Experimental findings

Area of Science:

• Cardiovascular Physiology
• Neuroscience
• Animal Models

Background:

• Psychological stress can impact cardiovascular function.
• The interaction between stress and acute coronary artery occlusion is not fully understood.
• Pigs serve as a relevant model for studying human cardiovascular responses.

Purpose of the Study:

• To investigate the hemodynamic, electrocardiographic, and coronary flow responses to psychological stress.
• To determine if psychological stress alters the susceptibility to arrhythmias during transient coronary artery occlusion.

Main Methods:

• 13 pigs were studied, divided into two groups: one without coronary occlusion and one with transient left anterior descending coronary artery occlusion.
• A psychological stressor (food presentation to fasting, restrained animals) was applied.
• Hemodynamic parameters, electrocardiograms, and coronary flow were monitored.
• Ventricular fibrillation incidence was compared between stress and non-stress conditions during occlusion.

Main Results:

• Psychological stress increased heart rate and arterial pressure in pigs without occlusion, with some evidence of coronary vasoconstriction.
• In pigs with coronary occlusion, psychological stress significantly increased the incidence of ventricular fibrillation (81.4 seconds mean time to onset) compared to non-stress conditions (only one animal).
• This increased susceptibility to arrhythmias occurred despite less severe ischemic indicators during occlusion under stress.

Conclusions:

• Psychological stress can precipitate life-threatening ventricular fibrillation during acute coronary artery occlusion in pigs.
• Stress may lower the threshold for arrhythmias in the setting of myocardial ischemia.
• These findings highlight the critical role of psychological factors in cardiovascular events.