Effect of Noise Reduction on Heart Rate Variability and Stress Response in Patients with Coronary Artery Disease after Percutaneous Coronary Intervention

Abstract

Background: Hospital noise pollution represents a major environmental stressor for patients with coronary artery disease (CAD), potentially affecting cardiovascular parameters and recovery outcomes. This study aims to investigate the effect of noise exposure on heart rate variability (HRV) and stress responses in CAD patients. Methods: A retrospective cohort study was conducted between January 2022 and December 2023 with 200 CAD patients who underwent percutaneous coronary intervention. In accordance with a temporal sequential design, 97 patients were treated in standard wards (January-August 2022), whereas 103 patients were treated in noise-controlled wards (November 2022-December 2023) after noise reduction protocols were implemented. Noise parameters, HRV indices [standard deviation of normal-to-normal intervals (SDNN), standard deviation of the averages of normal-to-normal intervals (SDANN) and low frequency/high frequency ratio (LF/HF)], salivary cortisol level, sleep quality [Pittsburgh Sleep Quality Index (PSQI)] and clinical outcomes were measured at preoperation and on postoperative day 5. Results: Noise levels were significantly lower in noise-controlled wards than in standard wards during daytime and nighttime hours (P < 0.001). After 5 days of hospitalisation, patients in noise-controlled wards exhibited significantly improved HRV parameters, including higher SDNN and SDANN, lower LF/HF ratios, lower salivary cortisol levels and better PSQI scores (P < 0.05), than those in standard wards. Additionally, patients in noise-controlled wards experienced shorter hospital stays and a lower incidence of recurrent angina (P < 0.05) than those in standard wards. Conclusions: Noise reduction in hospital wards significantly improved HRV parameters and reduced stress markers in CAD patients. The implementation of noise control measures may represent a cost-effective strategy to improve outcomes for CAD patients during hospitalisation.