Table 1

Definition of time stamps and intervals in STEMI screening and diagnosis

Symptom onset timeTime of symptoms prior to arrivalRecalled patient reported time for when symptoms associated with the acute STEMI encounter began.
Time zero
 Door timeED arrival time19
(primary analysis)
First recorded presence of the patient in the ED.
 First (early) ECG timeDoor to screening
Door-to-first-ECG time, D2E1st
(primary independent variable of interest)
ED arrival to completion of the first ECG. The first ECG is generally performed prior to the ED physician evaluation for the purpose of enabling the early identification of STEMI.
 Diagnostic ECG timeDoor-to-diagnostic ECG, D2ED x
(secondary independent Variable of Interest)
ED arrival to completion of ECG used to activate the cath lab.
 Cath lab activation timeDoor-to-catheterisation laboratory activationED arrival to the time when the cath lab was activated (Code STEMI).
 Patient arrives in cath labDoor-to-catheterisation laboratory arrival time,
diagnostic team centric
(primary outcome)
ED arrival to patient arrival in the cath lab.
 Balloon timeDoor-to-balloon time,
Intervention team centric outcome
(primary outcome)
Time from ED arrival to time the catheterisation guidewire crossed the culprit coronary lesion in patients receiving balloon angioplasty.
  • Time zero, start time for emergency care. Outcomes, treatment times for patient with STEMI directed to percutaneous coronary intervention. Cath Lab, cardiac  catheterisation laboratory; ED, emergency department.