Clinical consequences of ST-segment changes caused by body position mimicking transient myocardial ischemia: Hazards of ST-segment monitoring?

A case is described in which an acute ST-segment change, presumably due to a change in body position, is erroneously interpreted as an acute ischemic event. Positional ST-segment changes during continuous, multi-lead electroc ardiographic (ECG) monitoring are particularly challenging to distinguish f rom transient myocardial ischemia because 1) positional ECG templates are o ften not feasible to record at the beginning of monitoring in unstable pati ents; 2) positional ECG templates, if recorded, are often not readily acces sible to clinicians for later comparison; 3) body position cannot be correl ated with ST events because patients are out of the direct view of nurses d uring the event or clinicians review ST trends at a later time; 4) ST monit ors typically do not store ECGs frequently enough to be able to observe on the ST trend the gradual ("ramp-like") onset of ST changes that is characte ristic of transient ischemia; and 5) absence of chest pain with a ST event does not help clinicians identify false alarms because it is well understoo d that the majority of ischemic events are clinically silent.