Dynamical Landscape of Heart Rhythm in Discerning Erratic Rhythm in Elderly People

Abstract

We hypothesize that increase with age of short-term measures of heart rhythm [a way in which accelerations and decelerations appear], especially dynamical pattern indices [Transition Rates (ST) or self-Transfer Entropy (sTE)], provide indicates for unhealthy autonomic activity or cardiac tissue remodeling in elderly people. Hence they can help in early recognition of arrhythmogenesis processes. Based on properties of heart rhythm of 190 healthy persons, grouped into their age decade, we have found that both ST and sTE are efficient separators for discerning elderly people with erratic rhythm. The values in minimum in ST = 2.4 and minimum in sTE = 0.27, obtained by square function approximation, have been used to divide subjects of 70s and 80s into two groups. For all entropic measures these groups are different (p < 0.001, in t-test or Man-Whitney in case normality test failed). The fragmentation metrics [based on statistics of signs of heart rate changes] PPP and PAS also distingushed these groups though at greater p- value, and PSS yielded that the groups are identical. The minima of these function did not give satisfactory division of elderly into groups. Concluding, frequent changes in heart rate acceleration sign and size are the best signature for anomalous levels of short-term heart rate variability in elderly people.