Is it possible to exclude a diagnosis of myocardial damage within six hours of admission to an emergency department? Diagnostic cohort study ▸ Background: Patients with chest pain commonly present to emergency departments. In the UK, 30% of such patients are admitted to hospital for further investigation, and of those discharged around 6% may have significant myocardial damage. The authors set out to compare a six hour diagnostic protocol, which could reduce unnecessary admissions, against a gold standard test.

Method: Consecutive patients aged over 25 years with less than 12 hours of unexplained chest pain were included. Exclusion criteria were electrocardiographic (ECG) evidence of infarction or ischaemia, hypotension, arrhythmia or the need for admission on other medical or social grounds. The subjects underwent serial creatinine kinase MB measurements and continuous 12 lead ST segment monitoring for six hours. Patients were admitted to hospital if they had a positive creatinine kinase MB or developed an “important” ST segment change, as determined by a clinician. The gold standard tests were troponin T measurement at 48 hours or serial ECGs and cardiac enzymes over 24 hours.

Results: Of 383 patients attending, 368 completed the protocol and 292 completed follow up with gold standard testing. Fifty three patients tested positive on the diagnostic protocol, 47 on CK-MB measurements and six on ST monitoring. Altogether 239 patients were protocol negative. Of these 239 patients, 238 were also gold standard negative. The single false negative patient had a marginally increased troponin T and at one month remained well with no ECG changes. The sensitivity of the test was 97.2% (95% CI 95.0% to 99.0%), the specificity 93.0% (90.0% to 96.0%).

Conclusions: The six hour protocol effectively ruled out myocardial damage in patients with low to moderate …