Relationship Between Hypokalemia At The Early Stage Of Acute Myocardial Infarction And Malignant Ventricular Arrhythmia

Objective:To discuss the relationship between hypokalemia at the early stage of acute myocardial infarction (AMI) and malignant ventricular arrhythmia(MVA) as well as the features of hypokalemia.Methods:302 patients were involved in this study and conformed to the following conditions: they got AMI primarily, the course of the disease was within 24 hours, they accepted serum potassium test and Holter monitoring on admission, no these experiences such as using diuretics, hyperthyroidism, diabetes insipidus, primary hyperaldosteronism, vomiting or diarrhea resulted from gastrointestinal diseases. Relevant data including types of AMI, namely STEMI or NSTEMI; infarct sites of STEMI; time interval from onset of AMI to admission; whether or not hypokalemia(serum potassium≤3.5mmol/L) and MVA(including multiform ventricular tachycardia , sustained ventricular tachycardia, ventricular flutter, ventricular fibrillation and so on)were recorded.The relationship between hypokalemia and MVA was analyzed by distributing patients into two groups (hypokalemia and no hypokalemia). The relationship between the time interval and hypokalemia was observed by classifying patients according to the time interval from onset of AMI to admission, namely≤3h group or 3h-24h group. The relationship between types of AMI and hypokalemia was analyzed by distributing patients into groups of STEMI and NSTEMI. The reletationship between infarct sites and hypokalemia was observed by classifying patients according to the infarct sites of STEMI, with the anterior or extensive anterior wall infarction as group A and inferior, posterior wall, right ventricular infarction as group B.SPSS13.0 was used for statistical analysis. The categorical data was processed with chi-square test and p values below 0.05 were considered significant.Results:1 The incidence of hyokalemia for 24 patients within 3h from onset of AMI to admission was 37.5% .2 The incidence of MVA between the group with hypokalemia and without had significant difference(10.47% vs 3.36%,P<0.05).3 The incidence of hypokalemia between the group within 3h and group within 3h to 24h of time interval from onset of AMI to admission had significant difference(37.5% vs 15.47%,P<0.05).4 There was no significant difference in incidence of hypokalemia between the group of STEMI and NSTEMI (20.35% vs 12.68%,P>0.05).5 For the STEMI cases, there was no significant difference in incidence of hypokalemia between groups with infarction involving anterior or extensive anterior wall(including anterior, anterior + highlateral, anterior + anterolateral, extensive anterior, extensive anterior + high lateral) and infarction involving inferior, posterior wall or right ventricular(including inferior , posterior , right ventricular infarction and inferiorposterior, inferior + right ventricular, inferior + posterior + right ventricular, 25.88% vs 18.81%,P>0.05).Conclusion:At the early stage of AMI, hypokalemia was often present. The incidence of hypokalemia for patients within 3h from onset was 37.5%, which was much higher than that within 3h to 24h, showing that serum potassium tends to get normal as time goes on. MVA was close associated with hypokalemia at the early stage of AMI, which indicated that hypokalemia was a cause of death. There was no difference in incidence of hypokalemia between patients of STEMI and NSTEMI. There was no difference in incidence between patients with infarction involving anterior or extensive anterior wall and involving inferior, posterior wall or right ventricular. Doctors should pay attention to hypokalemia at the early stage of AMI and MVA associated with hypokalemia.