冠循環に関する研究—Na, K代謝について

Studies on the Coronary Circulation:On the Natrium and Potassium

I．緒言

　冠状静脈洞カテール法の発達にともない，心筋のAnoxia状態が心臓に種々な化学的及び生理学的諸変化をもたらすことが近時明らかにされて来た。なかでも心臓に対するAnoxiaと電解質，ことにKとの関係は古くから注目され，心筋An—oxiaは心筋よりKの游出を来すといわれ（Kehar　1935, Baetjer 1935, Dennis 1938），冠状静脈血漿K濃度の変動からもかかる所見を推測させる成績が報告されている^1）−3）。さらに生体に対するAnoxia負荷試験においても細胞内より細胞外にKの移動することが確められており^6）7），Anoxia状態が細胞内Kに与える影響は諸家により一致した見解が見られている。

　しかしながら，心筋に対するO₂諸量，あるいは酸塩基平衡諸量と心筋Na, Kとの関係について，その詳細はなお明らかでなく，本論文はかかる点の解明に関し，動物及び臨床例に冠状静脈洞カテーテル法を施行し，Anoxia負荷試験を含めて得られた興味ある成績を報告する。

The coronary sinus catheterizations were performed in 20 dogs and 34 clinical cases in order to study the sodium and potassium metabolisms in coronary circulation, which were also studied before and during anoxia test of 8% O₂ in dogs and 13% O₂ in some of human subjects.

A) Any correlations was not observed in dogs and patients between the change in coronary arterio-venous difference of serum sodium and potassium concentration (ΔNa and ΔK) and the change in ECG findings during anoxia test.

Any significant difference was not also found in the changes mentioned above between normal and ab-normal groups.

B) Animal experiment

During anoxia test, ΔNa tended to increase and ΔK decreased in most cases. ΔNa and ΔK shifted towards positive and negative, respectively, when the change in coronary venous O₂ pressure (Pcso₂) caused by anoxia was beyond about 10mmHg. And in the cases, in which arterial O₂ pressure (Pao₂) fell below about 30mmHg or Pcso₂ below 10mmHg during anoxia, ΔNa and ΔK became positive and negative, respectively.

The positive correlation was generally recognized between Paso₂ and ΔK.

In the cases, in which myocardial oxygen consumption (MOC) and myocardial oxygen extract coefficiency (MOEC) increased during anoxia test, ΔK became negative and ΔNa remained positive generally.

ΔK was in inverse proportion to MOEC.

In the cases, in which the changes in MOEC became negative by anoxia, ΔNa and ΔK changed towards positive and negaive, respectively.

This suggests that myocardium would be still in relative anoxic state, even when MOC and MOEC in-creased by anoxia test.

In the cases, in which arterial pH (pHa) were beyond about 7.30 and arterial CO₂ pressure (Paco₂) below about 40mmHg, ΔNa and ΔK tended to remain positive and negative, respectively.

This suggests that the change in acid-base balance had some influence on the change in ΔNa and ΔK during anoxic state.

C) Clinical cases

ΔNa and ΔK decreased during anoxia test in most cases. Such correlations as seen in animal experiment were obscure in clinical cases. We think this is due to the anoxic load in human subjects being not so heavy as in dogs.