[Metabolism of potassium in the acute phase of myocardial infarction].

The aim of the study was to evaluate changes in potassium level at 1 to 4 days in patients with acute myocardial infarction. The studies comprised 103 patients including 85 men and 18 women, aged from 31 to 90 years (mean age 56.7 +/- 11.7). A control group consisted of 51 patients (40 men, 11 women) aged from 34 to 74 years (mean = 56.7 +/- 10.7) on intensive diuretic therapy due to heart failure without myocardial infarction. In order to establish our own normal limits of potassium level in the blood serum and erythrocytes 20 healthy subjects (10 men, 10 women) aged 34 to 54 years (mean = 37.8 +/- 9.1) were studied. In patients with acute myocardial infarction and in control subjects serum potassium levels (Ks), erythrocyte potassium content (Ke) and urine potassium level (Ku) had been determined. Serum and erythrocyte potassium levels were assessed by Mayer method with the use of flame photometer. Urine potassium level was also determined by flame photometry. Values of serum and erythrocyte potassium level were given in mmol/l, and urine potassium levels in mmol/h. Ks, Ke and Ku values at 1 to 4 days were compared with one other and with levels in the control group and in healthy subjects as well as with values assumed as normal. At 1 day of the myocardial infarction Ks-3.87 +/- 0.58 mmol/l was significantly lower as compared with Ks at 2, 3 and 4 days and with values in the control group: Ks = 4.4 +/- 0.49 mmol/l and in healthy subjects: Ks = 4.2 +/- 0.36 mmol/l (p less than 0.0001). Ke levels at 1 and 2 days were 98.3 +/- 5.6; 99.2 +/- 5.3 mmol/l; significantly lower as compared with the levels at 4 days (Ke = 102.5 +/- 5.8 mmol/l p less than 0.05) and as compared with the levels in the control group: Ke = 104.5 +/- 6.1 mmol/l (p less than 0.05) and in healthy subjects: Ke-102.6 +/- 5.8 mmol/l (p less than 0.01). In contrast Ku level at 1 day of the infarction was 4.6 +/- 3.2 mmol/h and it was significantly higher as compared with excretion levels on the remaining days and in the control group: Ku = 2.7 +/- 0.7 mmol/h (p less than 0.0001). The present studies show changes in the potassium level in the acute phase of the myocardial infarction consisting in a decrease of Ks and Ke levels and an increase in Ku level, mainly at 1 day of the infarction.