In the isolated perfused dog heart, at constant coronary blood flow and heart rate, we studied the effect of altering CO 2 in the gas mixture from 5 to 15% on contractility, coronary resistance, myocardial O 2 consumption and K balance. Contractility, assessed by the developed force, and its derivative through a strain-gauge arch sewn to the left ventricle decreased to 54 ± 7% (p<0.01) and 59 ± 6% (p< 0.01), respectively from control values. Coronary resistance decreased to 79 ± 3% of control (p<0.01). The negative inotropic effect of hypercapnia was accompanied by a decrease in myocardial O 2 consumption to 68 ± 11% (p<0.01) of control value and a net uptake of K by the heart. The possibility of an exchange of H + by K + is suggested as a possible mechanism involved in the negative inotropic effect of hypercapnia.
|Translated title of the contribution||Effects of acute hypercapnia upon the myocardium: Contractility, coronary resistance, oxygen consumption and potassium balance|
|Number of pages||8|
|Journal||Acta Physiologica Latino-Americana|
|State||Published - Dec 1 1977|
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