10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 2 2013 (April - June) Acute Myocardial Infarction (AMI) is a major public health problem. Fifty percent of deaths associated with AMI are attributable to arrythmias which result due to myocardial ionic imbalance of cations Na lessThan sup greaterThan + lessThan /sup greaterThan ,Mg lessThan sup greaterThan +2 lessThan /sup greaterThan , Ca lessThan sup greaterThan +2 lessThan /sup greaterThan , and K lessThan sup greaterThan + lessThan /sup greaterThan . Present study aims to find serial change in cation levels in MI cases and their relationship to arrythmias. Methods: Seventy five patients admitted to Intensive Coronary Care Unit (ICCU) with provisional diagnosis of acute myocardial infarction constituted the study group. They were studied serially on 1 lessThan sup greaterThan st lessThan /sup greaterThan , 3 lessThan sup greaterThan rd lessThan /sup greaterThan and 7 lessThan sup greaterThan th lessThan /sup greaterThan day of infarction. Thirty subjects without any heart disease and renal pathology, who were seen in the outpatient departments and healthy volunteers were taken as controls. S.Mg+2, Ca+2, Na+ and K+ were measured in controls and study group and compared. Results: Mean values of all the cations were lowered on 1 lessThan sup greaterThan st lessThan /sup greaterThan day of MI in study group compared to controls (p lessThan 0.01). A strong association between low Mg+2 and low K+ levels in MI cases and development of arrythmias is observed (p lessThan 0.001). Conclusions: Serial estimation of S.Mg+2 can be used as a diagnostic test for MI. Estimation of S.Mg+2 and S.K+ can be used as prognostic markers in MI. DR. P.KIRANMAI M.D Acute myocardial infarction, arrythmias, Serum magnesium, Serum potassium 1190-1195