Although ATP and Persantin did not increase myocardial oxygen consumption and Cl-ET increased it, these three coronary vasodilators improved coronary circulation and increased oxygen pressure of coronary sinus blood (Pcvo
2), which represented the oxygen level of myocardium. But these three vasodilators showed different effects on systemic and pulmonary circulation, respectively. ATP decreased pulmonary veno-arterial oxygen difference and increased oxygen pressure of mixed venous blood (Pv^
-o
2), which represents the oxygen level of body tissue. On the contrary Cl-ET increased pulmonary veno-arterial oxygen difference and decreased oxygen pressure of mixed venous blood. The effects of Persantin were intermediate between ATP and Cl-ET. All these three coronary vasodilators decreased pulmonary artery pressure during low oxygen inhalation. Amplivix, which increased coronary blood flow continuously without changing aortic pressure and heart rate, showed similar effects as Cl-ET on systemic and pulmonary circulation.
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