Features of Spectral Estimates of the Photoplethysmographic Waveform Variability in Patients with Aortic Stenosis

Introduction — A well-known method for assessing the autonomic status of patients in clinical practice is the use of spectral estimates of finger's photoplethysmographic waveform variability (PPGV). However, these estimates have not been studied in patients with aortic stenosis. Therefore, this study aimed to identify in the PPGV spectrum the markers of autonomic dysfunction specific for patients with aortic stenosis. Methods — The study included 34 patients with aortic stenosis at the age of 54 (43, 67) years and 30 healthy subjects at the age of 34 (31, 36) years (data presented as median with lower and upper quartiles). The following spectral estimates of PPGV were evaluated: LF% (low-frequency band, 0.04–0.15 Hz, in the percentage of total spectral power, 0–0.4 Hz), HF% (high-frequency band, 0.15–0.4 Hz, in the percentage of total spectral power, 0–0.4 Hz), and LF/HF ratio. Results — The study revealed the statistically significant (p<0.05) differences in HF% and LF% values in patients with aortic valve disease compared with healthy people. LF% was increased by 2-4 times in group of patients with aortic stenosis, while HF% was increased by 1.2-7 times. The difference between the groups at LF/HF ratio was statistically insignificant. Conclusion — Patients with aortic stenosis are characterized by higher LF% and HF% values, relative to healthy people of comparable age.