Influence of ethyl alcohol when given alone or in combination with potassium and/or magnesium supplements on ventricular fibrillation threshold levels in laboratory rats.

Five groups of rats were studied in an investigation to determine whether changes in the ventricular fibrillation threshold (VFT) occur when ethyl alcohol (EtOH) is given alone or in combination with K+ and/or Mg2+ supplements; the first group (n = 20) served as controls, the second (n = 18) was given only EtOH, the third (n = 18) EtOH+KCl, the fourth (n = 16) EtOH+MgCl2, and the fifth (n = 18) EtOH+MgCl2 + KCl for a 9 month period. Two rats from each group were killed on each day. One rat heart was perfused using the Langendorff apparatus and the other used for tissue electrolyte analyses. A significant fall in the mean VFT (9.7 +/- SD 1.9 mA vs 4.5 +/- 1.6 mA; P less than 0.0001) was noted in the rats given EtOH solution as drinking water for 9 months, and a significant increase in the VFT levels was seen in the Mg(2+)-supplemented group (9.7 +/- 1.9 mA vs 18.9 +/- 4.1 mA; P less than 0.0001) and in the K+ + Mg2+ supplemented group (9.7 +/- 1.9 mA vs 15.8 +/- 1.3 mA; P less than 0.0001) compared to controls. In addition, an increase in the heart rate was observed in the group supplemented with Mg2+ (213 +/- 8 beats/min vs 231 +/- 10 beats/min; P less than 0.0001) as well as in the group supplemented with K+ + Mg2+ (213 +/- 8 beats/min vs 222 +/- 10 beats/min; P less than 0.002) compared to controls. There was no significant change in the coronary blood flow (CF) in any group.(ABSTRACT TRUNCATED AT 250 WORDS)