[Validity of clinical tests to confirm or exclude the diagnosis of acute myocardial infarction].
BACKGROUND
To know the clinical usefulness of the diagnostic tests habitually used to diagnose an acute myocardial infarction (MI), in a group of patients in which this diagnosis is clinically highly suspected.


METHODS
A cross sectional study was designed. The sample (n = 114) was randomized and selected by term and specific of days from the patients attending the Emergency Service at Elda General Hospital (Alicante, Spain) in a year period. The method we used was is a validity study, making 2 x 2 tables. The clinical outcome was the gold standard and was cross matched with some of the clinical criteria habitually used to diagnose acute myocardial infarction: thoracic pain character, irradiation, ECG findings and CK-MB levels.


RESULTS
Clinical suspicion of MI was confirmed in only 27.8% (IC--95%: 19.3-36.3). The best validity indexes of clinical usefulness to confirm the MI diagnosis were obtained from ECG findings (CP+ = infinity) and CK-MB (CP+ = 24.2 at the end of the observational period and CP = 17.9 at the beginning). The best negative clinical validity indexes were CK values obtained at the end of the observational period (CP- = 0.07) and the ECT findings obtained at the end of the observational period (CP- = 0.10).


CONCLUSIONS
Clinical carefulness is essential to avoid a diagnostic mistakes in MI patients, since the symptoms we used as a diagnostic guide do not offer good validity indexes. Changes in ECG or CK-MB levels could confirm the MI diagnosis but normal findings in both tests did not discard this diagnosis. We should keep the possibility of a mistake till the end of the observational period.
Departamento de Medicina, Universidad Miguel Hernández, Hospital Comarcal de Elda, Alicante.
V F
VF
Gil
E
E
Peinado
E
E
Obrador
R
R
Pascual
C
C
Pérez Barba
J
J
Merino
D000368:Aged; D003402:Creatine Kinase / Q000097:blood; D003430:Cross-Sectional Studies; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007527:Isoenzymes; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D011897:Random Allocation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D007527:Isoenzymes; D003402:Creatine Kinase