Diurnal Rhythm of Cardiac Troponin: Consequences for the Diagnosis of Acute Myocardial Infarction.

Background: Interpretation of serial high-sensitivity cardiac troponin (hs-cTn) measurements for the diagnosis of acute myocardial infarction (AMI) assumes random fluctuation of hs-cTn around an individual's homeostatic set point. The aim of this study was to challenge this diagnostic concept.

Methods: Study 1 examined the presence of a diurnal hs-cTn rhythm by hourly blood sampling, day and night, in 24 individuals without a recent history of AMI.

One-hour rule-in and rule-out of acute myocardial infarction using high-sensitivity cardiac troponin I.

Unlabelled: We aimed to prospectively derive and validate a novel 0-/1-hour algorithm using high-sensitivity cardiac troponin I (hs-cTnI) for the early "rule-out" and "rule-in" of acute myocardial infarction (AMI).

Methods: In a prospective multicenter diagnostic study, we enrolled 1,500 patients presenting with suspected AMI to the emergency department. The final diagnosis was centrally adjudicated by 2 independent cardiologists blinded to hs-cTnI concentrations.