NONINVASIVE ASSESSMENT OF LEFT-TO-RIGHT DIFFERENCES IN AUTONOMIC NERVOUS DISCHARGE TO THE HEART

We developed a noninvasive method to provide beat-to-beat changes in t he PR interval that accompany normal fluctuations in the heart rate. A well reproducible PR interval signal that fluctuated in a way similar to the heart rate exhibited spectral frequency distribution similar t o the heart rate, The PR interval and the heart rate signals were anal yzed in the PR interval-heart rate (PR-DR) diagram using our model of AV conduction. The observed PR-HR patterns could be explained by the m odel only when we assumed different neural inputs to the SA node and t he AV node, This suggests that noninvasive measurements of the PR inte rval signal could be used in the study of autonomic neural influences to the heart connected with the left and right distribution of the car diac nerves.