Influence of Developed Tension on Myocardial Potassium Balance in the Dog Heart
Experiments were carried out to determine the effect of changing preload on myocardial potassium balance. A blood-perfused dog heart was employed. Changes in the pressure recorded from a balloon in the left ventricle were assumed to reflect directional changes in myocardial wall tension. Developed tension was altered by changing the volume of the balloon. Net potassium balance was calculated as the product of the coronary A-V plasma potassium difference and coronary plasma flow. When the ventricle was developing little tension, it usually gained potassium. When diastolic volume and thus developed tension was increased, a net loss of myocardial potassium occurred. In some experiments the hemodynamic response of the ventricle to the increase in diastolic volume suggested that the contractility of the heart was increasing while the heart was losing potassium.
- ventricular tension
- myocardial K+ balance
- myocardial tension and potassium balance
- myocardial contractility
- Accepted March 30, 1968.
- © 1968 American Heart Association, Inc.