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- Title
Within-subject electrocardiographic differences at equal heart rates: role of the autonomic nervous system.
- Authors
Frederiks, Joost; Swenne, Cees A.; Kors, Jan A.; van Herpen, Gerard; Maan, Arie C.; Levert, Jeroen V.; Schalij, Martin J.; Bruschke, Albert V.G.
- Abstract
Various combinations of sympathetic and vagal tone can yield the same heart rate, while ventricular electrophysiology differs. To demonstrate this in humans, we studied healthy volunteers in the sitting position with horizontal legs. First, heart rate was increased by lowering the legs to 60° and back. Thereafter, heart rate was increased by handgrip. In each subject, a leg-lowering angle was selected at which heart rate matched best with heart rate in the third handgrip minute. Thirteen subjects had a heart rate match better than 1%. Heart rate (control: 65.2±9.0 bpm) increased to 72.1±8.7 (leg lowering) and to 72.1±8.8 (handgrip) bpm. QRS azimuth, QRS duration, maximal T vector, T azimuth, T elevation, ST duration, QRS-T angle and QT interval differed significantly (P<0.05) between leg lowering and handgrip (QT interval 418±15 versus 435±21 ms). Also, septal dispersion of repolarization, assessed as the time difference between the apex and the end of the T wave in the V2 and V3 leads, differed significantly (V2: 96.7±19.3 versus 110.0±23.3 ms, P<0.01; V3: 88.7±19.3 versus 97.3±23.3 ms; P<0.01). Hence, leg lowering and handgrip cause different ventricular depolarization and repolarization. The hypertensive handgrip manoeuvre entails a longer QT interval and probably an increased septal dispersion of repolarization.
- Subjects
ELECTROCARDIOGRAPHS; ELECTROCARDIOGRAPHY; HUMAN mechanics; NERVOUS system; HEART beat; NONCHROMAFFIN paraganglia
- Publication
Pflügers Archiv: European Journal of Physiology, 2001, Vol 441, Issue 5, p717
- ISSN
0031-6768
- Publication type
Article
- DOI
10.1007/s004240000487