Changes of extracellular Na+, K+, Ca2+ and H+ of the ischemic myocardium in pigs.
In open-chest pigs during severe myocardial ischemia [K+]e, [Ca2+]e and [H+]e increase, [Na+]e increases transiently reaching control values after 30 min. Extracellular osmolality of the ischemic area increases due to an H2O-shift from the ECS to the ICS. The increase of [Na+]e and [Ca2+]e must b explained by the shrinkage of the ECS due to the H2O-shift. The increase of [Ca2+]e is additionally caused by the decrease of pHe. The increase of [K+]e is mainly caused by the release of K+ from the ICS. The changes of [K+]e and [K+]i cause a decrease of the membrane potential to a range in which slow response potentials and re-entry excitations can occur. The increase of [K+]e therefore seems to be a major factor to cause early post-ischemic arrhythmias.
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D003250:Constriction; D003326:Coronary Circulation; D003327:Coronary Disease / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D013552:Swine
D007477:Ions; D012964:Sodium; D011188:Potassium; D002118:Calcium