Changes in heart rate variability during cognitive behavior therapy in depressed post-cardiac surgery patients: randomized controlled study

Abstract

Objective The aim of this research was to investigate if psychological rehabilitation impacts on heart rate variability (HRV) parameters changes in depressed post-CS patients. Methods HRV was analyzed in psychological intervention (PIG – cognitive behavior therapy (CBT) was applied, n=61) and usual care (UCG, n=64) groups of depressed post-CS patients. Depression was measured by using SCL-90R questionnaire. HRV parameters – heart rate (HR), general HRV (SDNN) and sympathetic activity index (LFC/HFC) were evaluated at physical rest over 5 minutes. The assessments were applied at 2, 12, and 24 months after CS. Eleven sociodemographic and biomedical factors were collected from medical records. Results After controlling for baseline imbalance (ANCOVA) findings have demonstrated improvement in PIG according to depression scores (F=15.7, p<0.001). The HRV analyses have shown significant change in LFC/HFC score in PIG (F=4.343, p<0.05), however this change have lost significance over second year. The PIG patients’ findings analyses have revealed that demographic/biomedical/personalities factors are related with some HRV parameters scores changes: education was related to HR changes (p<0.05), alexithymia - to SDNN changes (p<0.01), NYHA class and ejection fraction – to LFC/HFC (p<0.05 and p<0.001). Meanwhile other factors (age, gender, current smoking) were associated with the HRV parameters changes in UCG (p<0.05). Conclusion Positive changes in depression scores are related with better LFC/HFC dynamics after CBT, however later the positive change has lost its significance. In order to link multiple determinants for course of disease after CS, the complex interplay between mind and body have to be further investigated.