Thrombus laden plaque is sine qua-non of UA/NSTEMI . That’s what we have been taught ! right ? It may be true in many situations , but please remember there is another concept called demand ischemia , where in there is no active thrombus , still resting angina may occur due to increasing heart rate etc.
I just wanted to test how far this concept is understood , by the fellows in our coronary care unit . Following is story of a patient who arrived at CCU with angina at rest . I showed this ECG asked them the management .
History was purposefully blinded . 5/6 cardiologists wanted to admit the patient either in CCU or rush to cath lab. Heparin/ Fondaparuinux was prescribed by all. Tirofiabn was suggested by few.It is a high risk UA with left main disease some one mumbled .
I silently listened to them and revealed the history . This patient has just finished the exercise stress test , it was terminated as he had angina at peak exercise. and was reported as positive . A date was fixed for elective coronary angiogram. 10 minutes later ECG totally normalised , and the patient went home (Boarding a crowded Chennai city bus )
The fellows realised the importance of history . In fact no body asked for it ? I felt bad as all my fellows failed in this test That reflects bad teaching on my part !
What is the mechanism of ST depression here ?
- Fresh thrombus ?
- Mechanical occlusion ?
- High heart rate ?
- Combination of high rate and probable flow limiting lesion .
(Severe forms of stable angina can occur at rest . So do not equate all rest angina as true unstable angina !)
Final message
Do not label an ECG straightaway as acute coronary syndrome when there is baseline tachycardia and ST depression . Spare few minutes and apply your mind !
If a combination of ST depression and angina can be taken synonyms with UA every EST positive fellow should be labeled as UA and admitted in CCU. Please remember any tachycardia with a fixed tight lesion will mimic UA . Further , since there is no thrombus here and there is absolutely no role for heparin.
Dr.S.Venkatesan MD 
Leave a Reply