Wilkowska A, et al. - In this investigation, researchers assessed the change in the time domain of the heart rate variability (HRV) measure (standard deviation of all normal RR intervals) in patients following a first myocardial infarction (MI) based on the presence of depression. The study sample consisted of 22 patients hospitalized due to a first MI. Their depressive symptoms' severity was assessed via The Beck Depression Inventory. Investigators discovered that HRV was significantly lower in the depressed group vs patients without depression. In the first 6 months after the myocardial infarction, an increase in heart rate variability (HRV) was observed in both groups. Overall, the authors concluded that presence of depression after the MI is linked to a significant reduction of the time domain HRV measure (SDNN) and with its slower increase during at least a 3-month period.