Cardiac parasympathetic dysfunction related to depression in older adults with acute coronary syndromes.

Objective: To determine whether depression is associated with cardiac autonomic alterations in elderly patients with recent acute coronary syndromes (ACSs).

Methods: Cross-sectional study on the association between a major depressive episode or isolated depressive symptoms (21-item Hamilton depression score) and heart rate variability abnormalities in 56 adults (31 women, 55%) 60 years of age and older with a recent (24-72 h) myocardial infarction (MI) or unstable angina (UA).

Results: Spectral and nonspectral parameters of respiratory sinus arrhythmia, indicative of parasympathetic activity on the heart, were decreased in patients with depression (high-frequency heart rate variability [log ms(2)] 2.12+/-0.4 vs. 2.52+/-0.5, P=.024; pNN50 [%] 1+/-2 vs. 9+/-15, P=.006; and rMSNN [ms] 16+/-6 vs. 28+/-22, P=.009). Also, high-frequency heart rate variability decreased with increasing depressive symptom severity.

Conclusion: In a sample of older adults suffering from ACSs, depression was associated with impaired parasympathetic control of the heart.