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Gender difference in autonomic and hemodynamic reactions to abrupt coronary occlusion
K E Airaksinen1, M J Ikäheimo, M Linnaluoto
1Department of Medicine, University of Oulu, Finland. kari.airaksinen@.oulu.fi
Insights
Women exhibit greater vagal activation during abrupt coronary occlusion, potentially offering antiarrhythmic benefits. This gender-related difference in autonomic response may influence outcomes in acute coronary events.
Area of Science:
- Cardiovascular physiology
- Autonomic nervous system function
- Gender-based medicine
Background:
- Sudden cardiac death risk is higher in men post-myocardial infarction, with underlying reasons unclear.
- Cardiovascular autonomic regulation impacts acute coronary event outcomes.
- Physiological circumstances reveal gender differences in heart rate (HR) autonomic regulation.
Purpose of the Study:
- To investigate gender-specific differences in autonomic and hemodynamic responses to acute coronary occlusion.
- To explore the role of autonomic responses in gender-related outcomes of myocardial infarction.
Main Methods:
- Assessed changes in HR, HR variability, and blood pressure during 2-minute coronary occlusion in 140 men and 65 women undergoing coronary angioplasty.
- Analyzed the incidence of ventricular ectopic beats during occlusion.
- Used a control group to define nonspecific responses to balloon inflation.
Main Results:
- Women experienced more ST changes and chest pain during occlusion.
- Vagal activation (bradycardia, increased HR variability) was significantly more common in women (31% vs. 13% and 25% vs. 11%, respectively).
- Women showed a higher incidence of blood pressure decrease (28% vs. 11%) and Bezold-Jarisch-type reactions (16% vs. 0.7%). Female gender independently predicted bradycardic, hypotensive, and Bezold-Jarisch responses.
Conclusions:
- Vagal activation is more prevalent in women during abrupt coronary occlusion.
- This heightened vagal response in women may confer antiarrhythmic benefits.
- Gender-related differences in autonomic response could modify outcomes of acute coronary events.
Objectives:
We sought to determine whether there are gender-related differences in autonomic and hemodynamic responses to abrupt coronary occlusion.
Background:
The risk of sudden death before hospital admission is higher in men with an acute myocardial infarction. The reasons for this gender-related difference are not well understood. Cardiovascular autonomic regulation modifies the outcome of acute coronary events, and there are gender differences in the autonomic regulation of heart rate (HR) in normal physiologic circumstances.
Methods:
We analyzed the changes in HR, HR variability and blood pressure and the occurrence of ventricular ectopic beats during a 2-min coronary occlusion in 140 men and 65 women referred for single-vessel coronary angioplasty. The ranges of nonspecific responses were determined by analyzing a control group of 19 patients with no ischemia during a 2-min balloon inflation in a totally occluded coronary artery.
Results:
Women more often had ST segment changes (p < 0.01) and chest pain (p < 0.05) during the occlusion. Significant bradycardia or increase in HR variability as a sign of vagal activation occurred more often in women than in men (31% vs. 13%, p < 0.01 and 25% vs. 11%, p < 0.05, respectively). Coronary occlusion also more often caused (28% vs. 11%, p < 0.01) a decrease in blood pressure in women. The most pronounced female preponderance was in the incidence of Bezold-Jarisch-type reaction (i.e., simultaneous bradycardia and decrease in blood pressure [16% vs. 0.7%, p < 0.0001]). Logistic regression models developed to analyze the significance of gender while controlling for baseline variables and signs of ischemia identified female gender to be an independent predictor of bradycardic reactions (odds ratio [OR] 3.2, 95% confidence interval [CI] 1.4 to 7.7, p < 0.01), hypotensive reactions (OR 2.6, 95% CI 1.1 to 6.0, p < 0.05) and Bezold-Jarisch-type response (OR 22.2, 95% CI 2.5 to 200, p < 0.01). Significance of female gender as a protector against early coronary occlusion-induced ventricular ectopic beats emerged as having borderline significance (OR 0.4, CI 0.1 to 1.1, p = 0.07).
Conclusions:
Vagal activation is more common in women than in men during abrupt coronary occlusion and may have beneficial antiarrhythmic effects, modifying the outcome of acute coronary events.