BackgroundThis study investigated the effects of Islamic religious and breathing techniques with heart rate variability (HRV) biofeedback therapies on HRV and psycho-physiologic coherence (resonance frequency), depression and anxiety in coronary artery bypass graft surgery (CABG) patients.MethodsSixty CABG patients were chosen and randomly assigned to religious, breathing techniques and control groups. The experimental groups received 8 weeks of treatments; a 2-h session with home works in each week. The control group received only their normal hospital interventions. The groups’ depression, anxiety, HRV and psycho-physiologic coherence levels were assessed before and after the interventions by DASS-21 for depression and anxiety, and em-wave desktop software for HRV and psycho-physiologic coherence. The data were analyzed using ANCOVA with Bonferroni Comparison test and descriptive tests in SPSS software.ResultsThe findings showed that there were significant differences in psycho-physiologic coherence (HRV), depression and anxiety scores among the three groups in the post-tests. In fact, depression and anxiety were reduced more in the religious group, while psycho-physiologic coherence raised more in the breathing with the HRV feedback group.ConclusionThe results showed that both Islamic religious and breathing techniques with HRV biofeedback therapies can be used in rehabilitation programs for CABG patients in clinics and hospitals.