How much ST depression in V2 and V3 is acceptable before you suspect ischemia?

A 60-something woman with h/o bioprosthetic MV replacement and COPD, who is not on anticoagulants (bioprosthetic valves generally do not require anticoagulation), presented after 14 hours of left sided chest pain with radiation down left arm.  It woke her up at 0200.  She states that now it is worse with deep inspiration and associated with SOB.  Here is her triage ECG:What do you think?Here I magnify leads V2-V4:There is almost 1 mm ST depression at the J-point, relative to QRS onset, in lead V3.  We don ' t really know about lead V2 because it was placed too high (Negative P-wave shows that it was too high)There is a approximately 0.5 mm STD in V4.  Most individuals, at baseline, have ST Elevation in V2 and V3.  It is rare to have ANY baseline ST depression.This 2001 paper by Peter MacFarlane proves the point:Macfarlane PW. Age, sex, and the ST amplitude in health and disease. J Electrocardiol [Internet] 2001;34 Suppl:235 –41. Available from: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11781962In this paper, Dr. MacFarlane establishes that 97.5% ofapparently healthy females over age 50 (or any age, really) have STamplitude in lead V2 of greater than -0.2 mm (0.2 mm STD), and in V3 and V4 of greater than -0.5 mm (0.5 mm STD), as measured at the J-point, relative to the QRS onset.  See table pasted below.In other words, ANY ST depression greater than 0.2 mm in...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs