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- Title
Influence of the Cardiac Sympathetics on Left Ventricular Dynamics during Tachycardia.
- Authors
Bishop, Vernon S.; Horwitz, Lawrence D.
- Abstract
Increasing heart rate by atrial pacing in conscious, resting dogs resulted in declines in stroke volume (-0.40 ml/beat-kg/100 beats/min; p < 0.001), and left ventricular transverse internal diameter at end-diastole (-3.40 mm/100 beats/min; p < 0.001) and end-systole (-2.14 mm/100 beats/min; p < 0.001). When pacing was repeated following β-adrenergic blockade, stroke volume declined slightly more than had occurred during the control response. The decrease in end-diastolic diameter was -2.13 mm/100 beats/min while the end-systolic diameter declined at a rate of -0.93 mm/100 beats/min. It is concluded that loss of β-adrenergic tone limits stroke volume at high heart rates due to a diminished ability of the myocardium to shorten, as indicated by elevation in the left ventricular end-systolic diameter. Copyright © 1973 S. Karger AG, Basel
- Publication
Cardiology, 1973, Vol 58, Issue 6, p326
- ISSN
0008-6312
- Publication type
Article
- DOI
10.1159/000169650