Additional predictive value of serum potassium to Thrombolysis In Myocardial Infarction risk score for early malignant ventricular arrhythmias in patients with acute myocardial infarction

• Published in: The American journal of emergency medicine 2012-09, Vol.30 (7), p.1089-1094
• Main Authors: Su, Jianling, MD, Fu, Xianghua, MD, PhD, Tian, Yingping, MM, Ma, Yuteng, MM, Chen, Hui, MD, Wang, Yanbo, MD, Wang, Xuechao, MD, Liu, Huining, MD
• Format: Article
• Language: English
• Subjects: Adult; Age Factors; Aged; Aged, 80 and over; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Blood; Cardiology. Vascular system; Coronary heart disease; Diabetes; Emergency; Emergency medical care; Family medical history; Female; Heart; Heart attacks; Hospitalization; Humans; Hypertension; Hypokalemia - blood; Hypokalemia - complications; Hypokalemia - diagnosis; Intensive care medicine; Male; Medical sciences; Middle Aged; Mortality; Multivariate analysis; Myocardial infarction; Myocardial Infarction - blood; Myocardial Infarction - complications; Myocardial Infarction - diagnosis; Potassium - blood; Predictive Value of Tests; Retrospective Studies; Risk Factors; ROC Curve; Sex Factors; Software; Statistical methods; Variables; Ventricular Fibrillation - blood; Ventricular Fibrillation - diagnosis; Ventricular Fibrillation - etiology
• ISSN: 0735-6757; 1532-8171
• DOI: 10.1016/j.ajem.2011.07.009

Abstract Objective The aim of this study was to evaluate the additional predictive value of serum potassium (SK) to Thrombolysis In Myocardial Infarction (TIMI) risk score for malignant ventricular arrhythmias (MVA) in patients within 24 hours of acute myocardial infarction (AMI). Methods This was a 6-year retrospective study. The receiver operating characteristic curve was used to evaluate the predictive value of SK and TIMI risk score for MVA attack. In addition, SK-modified TIMI risk score was created by incorporating SK information into the usual score; the accuracy of new score was compared with that of the usual TIMI risk score by comparing the area under the receiver operating characteristic curves (AUC). Results Among the 468 patients enrolled, the incidence of MVA 24 hours after AMI was 9.4%, and it was higher in the hypokalemia group compared with that of the normokalemic group (27.3% vs 7.5%, P < .001; odds ratio, 4.594; 95% confidence interval [CI], 2.159-9.774). A significant predictive value of SK was indicated by AUC of 0.787 (95% CI, 0.747-0.823, P < .01). Serum potassium remained a predictor of MVA after being adjusted by the variables in TIMI risk score. The AUC of TIMI risk score in relation to MVA was 0.586 (95% CI, 0.54-0.631; P = .0676). The incorporation of SK into TIMI risk score improved its predictive value for MVA attack (AUC = 0.66; 95% CI, 0.568-0.753; P < .001), with significant difference between AUC of the new score and that of the original risk score ( Z = 2.474, P = .013). Conclusions Serum potassium on admission to the emergency department may be used as a valuable predictor and could add predictive information to some extent to TIMI risk score for MVA attack during 24-hour post-AMI.