A NEW METHOD OF ASSESSING CARDIAC AUTONOMIC FUNCTION AND ITS COMPARISON WITH SPECTRAL-ANALYSIS AND COEFFICIENT OF VARIATION OF R-R INTERVAL

A new non-linear method of assessing cardiac autonomic function was ex amined in a pharmacological experiment in ten healthy volunteers. The R-R interval data obtained under a control condition and in autonomic blockade by atropine and by propranolol were analyzed by each of the n ew methods employing Lorenz plot, spectral analysis and the coefficien t of variation. With our method we derived two measures, the cardiac v agal index and the cardiac sympathetic index, which indicate vagal and sympathetic function separately. These two indices were found to be m ore reliable than those obtained by the other two methods. We anticipa te that the non-invasive assessment of short-term cardiac autonomic fu nction will come to be performed more reliably and conveniently by thi s method.