A new method for the PP-PR hysteresis phenomenon enhancement under exercise conditions

Abstract

A non-linear relation between PR and PP intervals has been established in a previous work under maximal and graded exercise test as well as under pyramidal exercise where the effort is not released abruptly This study presents a new method whose aim is to exhibit more clearly the hysteresis behavior of this non-linear relation under graded exercise. After the description of the initial approach, we propose a second one which can provide a better estimation of the PR intervals. Moreover pooling the results of these two methods leads to an improvement of the estimation accuracy of PR intervals and then the hysteresis. It is well known that a hysteresis behavior exists at AV node's level, between the refractory period and the repolarization period. Besides, the autonomic neural system also acts upon the cardiac activity during an intense effort. Therefore, hysteresis which links the "PR interval vs PP interval" seems not be explained only at the cellular level; the heart must be viewed in his global context considering the nervous system