Thursday, November 20, 2008

Two cases of ST depression

NSTEMI with subtle ST depression.

EKG from 11-12. Symptoms on 11-12 were also subtle, but present for 5 days, so if a single troponin was sent, it might have been positive. Pt. returned 2 days later (11-14) with similarly difficult symptoms [right neck pain, bilateral foot swelling (due to increase in amlodipine dose), recurrent abd pain (CT 2 days earlier had shown massive amount of stool), BRBPR and heme positive stools, and an aside that this abdominal pain goes up "into my esophagus and left neck." The ECG shown is from 11-12 and is the most diagnostic, with ST depression in V4 and V5. V3 is slightly negative. There is also a long QTc (484ms) and large T waves in V2-V4. These "hyperacute" T waves can be due to acute LAD ischemia OR due to posterior reperfusion (patient is pain free, posterior wall motion abnormality, posterior artery). In this case it is the latter. REMEMBER: in V2 and V3, there is almost always some ST elevation. Absence of ST elevation may be relative depression. A troponin on 11-14 was 2.0 and going down. It might have been much more elevated if measured on 11-12. The ECG pon 11-14 had very minimal ST depression. Cath showed occluded RCA and large OM, 80% LAD (severe 3-vessel disease).

THE SECOND CASE is ST depression from hypokalemia. The patient was a 17 year old with syncope. She has tachycardia of unknown etiology. There is diffuse ST depression. There is no CP or SOB. I guessed it would be 2.4, but it was actually 3.0. There is more ST depression than one usually finds with a K of 3.0. Notice there is a bump just before the P wave (leads II, III, V3-V5). One might be tempted to call this a T-wave. But it is a U-wave. The ECG completely normalized with K supplementation.

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