Abstract
The H2 catheter electrode was applied for the determination of the coronary blood flow to ascertain its applicability. First, a modified catheterization technique was newly introduced to facilitate the placing of the catheter tip in the coronary sinus. Secondly, using this technique, the catheter electrode was inserted into the coronary sinus of dogs. Then, the H2 currents were measured in the aorta, coronary sinus and right atrium during the H2 inhalation to obtain the blood flow rate per unit volume of the heart tissue. This flow measurement was performed under three different experimental conditions of hypoxic respiration, epinephrine infusion and intravenous injection of carbochromen.
In comparison of the present results with the previous data obtained by other authors, it was demonstrated that the H2 current had sufficient accuracy and reproducibility to show the changes in coronary blood flow continuously over the long run of the experiment lasting for several hours. Unlike the results in the N2O method based on the coronary sinus blood sampling, the H2 desaturation curves recorded in the coronary sinus formed a straight line on the semilogarithmic scale. This suggested that the coronary blood flow observable in the coronary sinus might be almost uniform.
