title: Serum, lymphocyte, and erythrocyte potassium, magnesium, and calcium concentrations and their relation to tachyarrhythmias in patients with acute myocardial infarction.
abstract: Serum, lymphocyte, and erythrocyte potassium, magnesium, and calcium levels were measured in 215 patients during the five days following acute myocardial infarction. Serum potassium fell from 4.25 +/- 0.05 to 4.08 +/- 0.06 mmol/liter (p less than 0.001), magnesium from 0.93 +/- 0.01 to 0.85 +/- 0.01 mmol/liter (p less than 0.001), and calcium from 2.4 +/- 0.02 to 2.2 +/- 0.08 mmol/liter (p less than 0.001). Lymphocyte potassium increased from 18.1 +/- 1.5 to 51.6 +/- 4.3 pmol/100 cells (p less than 0.001) and magnesium from 2.0 +/- 0.1 to 8.2 +/- 0.8 pmol/100 cells (p less than 0.001), whereas calcium decreased from 2.9 +/- 0.27 to 1.4 +/- 0.25 pmol/100 cells (p less than 0.001). Erythrocyte cations remained constant. There was a larger increase in lymphocyte potassium in patients with tachyarrhythmias than in patients without (70.4 and 46.9 pmol/100 cells, respectively, p less than 0.001), whereas the presence of a high lymphocyte magnesium level was associated with a significant decrease in the development of tachyarrhythmias, despite high potassium concentrations. It is suggested that lymphocyte cation concentrations mirror myocardial interstitial concentrations and that a high interstitial magnesium level has a protective effect on the increased cell excitability due to, and despite, a high interstitial potassium level.
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D002118:Calcium / Q000097:blood*; D004912:Erythrocytes / Q000032:analysis; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000032:analysis; D008274:Magnesium / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000150:complications; D011188:Potassium / Q000097:blood*; D011446:Prospective Studies; D013610:Tachycardia / Q000097:blood* / Q000209:etiology
chemical_list: D008274:Magnesium; D011188:Potassium; D002118:Calcium