Should the 1h algorithm for rule in and rule out of acute myocardial infarction be used universally?

A key problem in the emergency department is the prompt identification of patients with myocardial infarction. While this is not a diagnostic challenge in ST elevation myocardial infarction as the ECG is usually unmistakable, in non ST elevation myocardial infarction (NSTEMI) the diagnosis is more complex and based on information derived from detailed clinical assessment, ECG and biomarkers. The ideal biomarker should allow an accurate and immediate identification of patients with NSTEMI. We do not have this ideal biomarker yet. The best approximation is currently represented by high sensitivity cardiac troponin (hs-cTn). In particular, the hs-cTn 0h/1h-algorithm proposed in the European Society of Cardiology Guidelines on the management of NSTEMI might allow a rapid ‘rule in’ and ‘rule out’ of a large proportion of patients with suspected NSTEMI. A critical question is: ‘Should the 1h algorithm for rule in and rule out of acute myocardial infarction be used universally?’. This approach might substantially speed up the triage of patients with suspected NSTEMI. Yet, some concern has recently been raised on this universal application regardless of symptom duration, overall clinical risk and sex. In the following debate key opinion leaders give their answers to this important question with major clinical implications. Finally, it is worth mentioning that this is a rapidly moving field and I anticipate that a new stimulating debate will soon be needed.