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Independent Autonomic Modulation of the Human Sinus and AV Nodes : Evidence From Beat‐to‐Beat Measurements of PR and PP Intervals During Sleep
Author(s) -
KOWALLIK PETER,
MEESMANN MALTE
Publication year - 1995
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.1995.tb00376.x
Subject(s) - medicine , beat (acoustics) , cardiology , tonic (physiology) , autonomic nervous system , heart rate , heart rate variability , sinoatrial node , blood pressure , physics , acoustics
Autonomic Modulation of Sinus and AV Nodes. Introduction : Evidence from animal experiments indicates that the autonomic nervous system may influence the sinus (SA) and atrioventricular (AV) nodes differently. We investigated, therefore, whether there are spontaneous functional differences in the innervation of the SA and AV nodes in man. Methods and Results : This study was performed in 10 healthy males (ages 21 to 26 years) during strict bed rest from 10 pm to 6 am. Three ECG leads were digitized on‐line. PR and PP intervals were determined on a heat‐to‐beat basis off‐line using a correlation algorithm with an accuracy of ± 2 msec and were verified visually. During; major body movements, there were sudden decreases in PP intervals of 36 to 827 msec (mean 335) for periods of 6 to 265 seconds (mean 24), During these phases of heart rate (HR) acceleration, PR intervals showed either concomitant shortening (9 to 30 msec), no change, or lengthening (6 to 25 msec). Furthermore, tonic changes in the PR interval occurred over 15‐minute periods during which the range of PP intervals was constant. Additionally, recovery‐adjusted PR interval (PR ‐ b 2 /RP) and cycle length were negatively correlated for some periods, which confirmed independent autonomic effects on SA node and A V node. Conclusion : Beat‐to‐beat measurement of PR intervals allows for evaluation of autonomic effects on the human AV node. The different patterns in PR intervals during sudden spontaneous increases in HR and the tonic changes in PR interval indicate that the autonomic inputs to the SA and AV nodes are, in principle, independent of each other.