SinusCor: an advanced tool for heart rate variability analysis

Background: Heart rate variability (HRV) is a widespread non-invasive technique to assess cardiac autonomic function. Time and frequency domain analyses have been used in HRV studies, and their interpretations are linked with both clinical prognostic and diagnostic information. Statistical and geometrical parameters, Fast Fourier Transform and Autoregressive based periodograms are commonly used approaches for the assessment of stationary RR intervals (RRi) signals. However, some conditions result in non-stationary HRV behavior such as the "tilt test" and exercise. This study presents the SinusCor, a new free software for HRV analysis that includes the classical time and frequency domain indices and also techniques for non-stationary data analyses in both time (i.e. root mean squared of successive differences; RMSSD calculated with moving segments) and frequency domains (i.e. time-frequency analysis). Results: An example of RRi was acquired from a young male subject and its time and frequency domain indices were calculated. Time-varying and time-frequency analyses were also presented using the RMSSD and total power, respectively. Validation of the present software against a standard software for HRV analysis (Kubios v 3.0.1) was also performed [SinusCor vs. Kubios: RMSSD-93.96 (41.55) vs. 93.96 (41.55) ms; SDNN-101.29 (29.03) vs. 101.29 (29.03) ms; LF-50.42 (19.76) vs. 50.56 (19.56) n.u.; HF-49.57 (19.76) vs. 49.38 (19.56) n. u.; LF/HF-1.38 (1.08) vs. 1.38 (1.07)]. Conclusions: SinusCor might be a useful tool for classical stationary and non-stationary HRV analysis.