+ EKG Interpretation
Dr. Ohlbaum's Explanation
This patient is a 68 year old man with known CAD s/p CABG, ischemic cardiomyopathy and intermittent afib in addition to dm and htn who presented to the ed with abdominal pain. I included an old ekg. The rhythm is irregular and there are no P waves➔ atrial fib.
The QRS is wide and it fits the criteria for LEFT BUNDLE BRANCH BLOCK:
- QRS > or= 0.12 secs
- broad monophasic R in I and VS and V6 and absence of Q's in those leads
- delay of onset of intrinsicoid deflection (time from start of QRS to point it begins to rapidly return to normal is long) in VS and V6
- displacement of ST segment and T wave in a direction opposite to the QRS (that means that where the QRS is down as in Vl and V2 the ST is elevated and the Tis upright and in VS and V6 where the QRS is up the ST is depressed and Tis inverted).
So, now for the difficult problem. The patient has known CAD and diabetes and has abdominal pain, is he having a STEMI??? This is a difficult problem. LBBB often seen in patients with LAD disease and can be caused by an acute Ml. And patients with LBBB have ST elevation in anterior leads by above criteria making diagnosis of an acute STEMI very tricky. Some people feel that any new LBBB in a patient with chest pain should be treated as a STEMI. This patients LBBB is not new which is somewhat reassuring but we do not want to miss a STEMI Cardiologists have come up with criteria and scoring systems to dx acute STEMI along with a LBBB.
- Concordant ST elevation > 1mm in leads with a positive QRS complex (score 5)
- Concordant ST depression > 1 mm in V1-V3 (score 3)
- Excessively discordant ST elevation > 5 mm in leads with a -ve QRS complex (score 2).
- At least one lead with concordant ST-elevation
- At least one lead of Vl-3 with concordant ST depression
So what do you think?
- Does he have ST ELEVATION in a lead like I or AVL or V6 where he has a positive QRS? NO
- Does he have ST DEPRESSION in Vl 2 or 3? NO
- Is his ST elevation in Vl-4 >20% of the S wave? NO IT IS NOT
SO THIS IS A LBBB, that is NOT new and does NOT have criteria suggesting a STEMI on top of his LBBB
See another patient who did fill those criteria below:
Life in the Fast Lane: Sgarbossa's Criteria