Abstract
BACKGROUND: Coronary artery disease (CAD) is intricately associated with physiological and psychological stress, which can negatively affect cardiac autonomic control. Heart rate variability (HRV), a noninvasive indicator of autonomic nervous system function, has become an important instrument for evaluating stress levels. MATERIALS AND METHODS: A cross-sectional observational study was performed on 100 patients diagnosed with coronary artery disease at a tertiary care facility during a 6-month duration. The Perceived Stress Scale (PSS-10) was utilized to evaluate standardized psychological stress. Heart rate variability (HRV) was measured using a 5-minute electrocardiogram (ECG) in a supine resting position, with subsequent analysis of both time-domain (SDNN, RMSSD) and frequency-domain (LF, HF, LF/HF ratio) parameters with Kubios HRV software. Patients were classified into low, moderate, and high stress categories according to PSS ratings, and HRV value. RESULTS: Among 100 participants, 38% exhibited high stress levels, 42% demonstrated moderate stress, and 20% reported low stress scores. A notable decrease in SDNN and RMSSD values was seen in the high stress group (SDNN: 23.5 ± 7.2 ms; RMSSD: 18.3 ± 5.6 ms) relative to the low stress group (SDNN: 42.8 ± 10.4 ms; RMSSD: 34.1 ± 8.9 ms) (P < 0.001). The frequency-domain characteristics indicated a larger LF/HF ratio in the high-stress group (3.1 ± 1.2) compared to the low-stress group (1.4 ± 0.6). Pearson's correlation indicated a robust negative association between PSS scores and RMSSD (r = -0.68, P < 0.001). CONCLUSION: HRV research reveals substantial changes in CAD patients under psychological stress, signifying diminished parasympathetic activity and autonomic dysregulation.