Association between depression and heart rate variability in patients after cardiac surgery: a pilot study.
OBJECTIVE
Depression is a risk factor for cardiovascular diseases. Reduced heart rate variability (HRV), which reflects altered autonomic nervous system activity, has been suggested as one of the mechanisms linking depression to cardiovascular diseases. However, the relationship between depression and HRV has not yet been investigated in patients undergone cardiac surgery. Therefore, the main aim of this study was to examine whether postoperative depression could be related to reduced HRV.


METHODS
Eleven patients with depression and 22 patients without depression, who had undergone cardiac surgery, were enrolled postoperatively. In all patients, HRV was derived from a four-minute blood volume pulse recording at rest. Analyses of covariance and partial correlations, while controlling for anxiety, were used to examine the associations between postoperative depression and each HRV parameter.


RESULTS
Compared to non-depressed patients, patients with depression showed significantly lower standard deviation of N-to-N intervals (SDNN) (p=.02), root mean square successive difference of N-to-N intervals (rMSSD) (p=.001), and high-frequency power (p=.002). Partial correlation analyses showed that depression was inversely related to SDNN (r=-.49, p=.005), rMSSD (r=-.58, p=.001), and high-frequency power (r=-.41, p=.02), whereas it was unrelated to other HRV parameters (p's>.09).


CONCLUSIONS
The current findings extend the depression-reduced HRV relationship to the patients after cardiac surgery. Also, our study suggests that postoperative depression is more likely to be associated with reduced vagal modulation on the heart than with excessive sympathetic activity.
Department of Preventive and Rehabilitative Cardiology, Motta di Livenza Hospital, Italy. elisabetta.patron@studenti.unipd.it
Elisabetta
E
Patron
Simone
S
Messerotti Benvenuti
Giuseppe
G
Favretto
Carlo
C
Valfrè
Carlotta
C
Bonfà
Renata
R
Gasparotto
Daniela
D
Palomba
D000368:Aged; D001007:Anxiety / Q000503:physiopathology / Q000523:psychology; D001341:Autonomic Nervous System / Q000503:physiopathology*; D006348:Cardiac Surgical Procedures / Q000523:psychology*; D003863:Depression / Q000503:physiopathology* / Q000523:psychology; D003866:Depressive Disorder / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D012307:Risk Factors; D011795:Surveys and Questionnaires