Objectives: We investigated associations between depressive symptoms and reduced heart rate variability (HRV) in women aged 30-65 years after an acute coronary event.
Background: Younger women have an increased mortality after myocardial infarction compared with men of similar age. Depression was hypothesized to contribute to the poor prognosis, possibly mediated by increased susceptibility to arrhythmias.
Methods: The Stockholm Female Coronary Risk study comprised of 292 women aged 30-65 years who were consecutively admitted for myocardial infarction or unstable angina pectoris during a 3-year period. Depressive symptoms were assessed by means of a 9-item questionnaire. Women with no or only one depressive symptom were classified as low-depression individuals, those with two or more depressive symptoms as high-depression individuals. HRV data were calculated from 24-h ambulatory electrocardiographic recordings 3-6 months after the initial event.
Results: Reliable HRV data were obtained from 266 patients. Seventy women were low-depression individuals, and 196 women were high-depression individuals. In univariate analyses, the index of standard deviations of R-R intervals, very low-frequency power, low-frequency power and high-frequency power of HRV were lower in the high-depression individuals. After controlling for potential confounders (diabetes, hypertension, systolic blood pressure, body mass index and β-blocker medication), a significant difference between low and high-depression individuals was maintained for all indices except for high-frequency power.
Conclusion: The presence of two or more depressive symptoms was associated with reduced HRV in a high-risk group of younger women after an acute coronary event.