Abstract Body (Do not enter title and authors here): Background: Although CHD incidence is low amongst young and middle-aged women, those who have premature MI are at a high risk of mortality. Greater psychosocial exposures and mental health comorbidities in women may play a role. We hypothesize that women age ≤ 60 years with recent MI have a higher burden of everyday negative psychological experiences, and that these are associated with greater real-time cardiac autonomic dysfunction compared with men.

Methods: We examined real-time mood and autonomic function in 239 participants aged ≤ 60 years with an MI within 8 months. We performed smartphone-based ecological momentary assessments of stressful events and negative mood states (anger, anxiety, distress, loneliness, and sadness) at 3 random points throughout the day for one week. Participants simultaneously wore a Holter monitor to measure autonomic function. Our primary exposure was the average negative mood intensity (rated 0 to 10) throughout the week, and our primary outcome was reduced deceleration capacity of heart rate (DC) during sedentary periods as a measure of lower vagal activity. Other measures of dysautonomia included lower high (HF) and low frequency (LF) heart rate variability (HRV). We used multivariable linear regression models to adjust for potential confounders.

Results: The mean age was 52 years, 51% were black, and 36% were women; 76% of women reported at least one stressful event in the week of monitoring, vs. 64% of men (p=0.04). Women reported more negative mood than men by 0.39 units (p=0.02) on average. DC, averaged across the week, was 12% lower, LF HRV was 41% lower, and HF HRV was 34% lower in women than in men. As the weekly average of negative mood increased, the weekly average of DC declined in women only (Figure). After adjusting for age, current smoking, diabetes, and beta-blocker use, each 2-point increase in the negative mood score was associated with a 12% (95% CI: 6.12%-17.88%) lower DC in women only. Similar findings were observed for HF and LF HRV.

Conclusions: Young and middle-aged post-MI women reported more real-time negative psychological states, which were associated with worse autonomic function compared to men with early MI. Resting autonomic function was also lower in women. Negative mood in daily life has disproportionate impact on cardiac autonomic regulation among women. Psychophysiological mechanisms are important in the examination of sex-based disparities in CHD pathophysiology and outcome.