Psychological risk factors are related to sympathetic activity according to the heart rate variability parameters during mental stress, orthostatic test and rest in post-cardiac surgery patients

Abstract

Background: To research if alexithymia, hostility, depression, anxiety, and distress are related to sympathetic activity according to the heart rate variability (HRV) parameters at rest and as responses to active orthostatic test (AOT) and to mental/arithmetic stress test (MST) in depressed post-cardiac surgery pts. Method: 74 post-cardiac surgery depressed pts (mean age 62.4±10.3 yrs, 67.6% male, SCL-90R depression subscale score N60 T) at 1.5 month after surgery filled in TAS-20 and SCL-90R questionnaire. HRV data were measured using short-termECG 5-minute recordings at rest, during AOT andMST. There was assessed heart rate (HR), standard deviation of RR intervals (SDNN), low frequency (LFnu) and high frequency (HFnu) components, and sympathetic activity index (LF/HF) at each period and the responses to AOT and to MST. Data were analysed with the SPSS for Windows version 13.0 statistical package (SPSS Inc., Chicago, II). Results: This study demonstrated, that TAS-20 was significantly related to LFnu during AOT (p=0.04, ß=0.280, 95%CI= 0.018- 0.757; F2: p=0.012, ß=0.260, 95%CI=0.328-2.543). Depression was associated with LFnu response to mental stress (p=0.015, ß=-0.295, 95%CI = -1.605 – [-0.175]), with HR at rest (p=0.005, ß=0.339, 95%CI=0.205-1.114), with HR during MST (p=0.014, ß=0.298, 95%CI=0.130-1.133), and with LF/HF during MST (p=0.028, ß=0.268, 95%CI = 0.009-0.163). It was estimated significant relationship between Anxiety and HR at rest (p=0.002, ß=0.254, 95%CI=0.02-0.706), between Anxiety and HR during AOT (p=0.038, ß=0.254, 95%CI=0.02-0.706). Global Severity Index was related to HR at rest (p=0.006, ß=0.333, 95%CI=0.125-0.715) and during MST (p=0.047, ß=0.243, 95%CI=0.004-0.664). The findings of this research suggest, that almost all investigated PRF for cardiovascular diseases are related to one or more sympathetic HRV parameters – LF power, HR or LF/HF in depressed post-cardiac surgery pts. Therefore, alexithymic, depressed, anxious, or distressed post-cardiac surgery pts may be at higher risk of rhythm disorders or sudden cardiac death. The pts must be screened for such PRF and must be informed about the results - as such findings would be important for the motivation for the psychological rehabilitation. There was small number of the pts in this study, so we suggest, that PRF associations with parameters of HRV could be confirmed better by larger multicenter studies.