In-vivo and isolated HRV analysis by Hidden Markov model

Analysis of details of heart rate variability (HRV) series may improve diagnosis of nervous system activity. The aim of this study was to quantify oscillation character in HRV series details with usage of Hidden Markov model (HMM). Five New Zealand white rabbits and five isolated New Zealand rabbit hearts at Langendorff setup were studied. All oscillation-related coefficients of HMM transient matrix were significantly lower in isolated heart HRV series than in in-vivo ones. Significant tendency to compensate immediately the changes in RR interval duration is characteristic for isolated heart. Compensation process is very prompt, based on only one previous RR interval.