Actual situation regarding cardiac etiology determined by clinical diagnosis of and medical examiner's postmortem findings on witnessed out-of-hospital cardiac arrest cases.

Aim: To examine indicators that may assist in the diagnosis of cardiac etiology using simple tests in witnessed cardiac etiology out-of-hospital cardiac arrest cases, which is emphasized in the Utstein Style. Method: The subjects were 165 witnessed cardiac etiology out-of-hospital cardiac arrest cases, which were transported to Kobe University Hospital during the five-year period between January 1, 2005 and December 31, 2009. A comparative study was conducted into whether there were any significant differences in the initial electrocardiogram (ECG) and the various early diagnostic markers of acute myocardial infarction between the group who were finally diagnosed as being of cardiac etiology and the group who were finally diagnosed as being of non-cardiac etiology. Results: Of the 165 witnessed cardiac etiological cases, 69 cases were finally re-classified as non-cardiac etiological cases on the basis of scrutiny after admission or postmortem findings by the Medical Examiner. Ventricular fibrillation shown in the initial ECG and Qualitative cardiac troponin T test positive were significantly higher in the final diagnosis cardiac group than in the final diagnosis non-cardiac group. Ventricular fibrillation and troponin T positive can be seen as significant indicators in determining whether a case was cardiac or non-cardiac, and the model χ 2 test result of p < 0.01 in the multiple logistic regression analysis was significant, and the determining predictive value was 65.4%. Conclusion: The indicators which should be noted in simple tests to improve the precision of discrimination of cardiac etiology in out-of-hospital cardiac arrests are ventricular fibrillation in the initial ECG and the qualitative test of cardiac troponin T.