73 yo M PMH of CAD, HFpEF, HTN, cocaine abuse presented with a single episode of chest pain and sob which began 3 days prior while walking after using cocaine that day. CP was R sided, non radiating, lasted seconds, sob lasted about 20 min.
Vital Signs: BP 159/93HR 84 RR 19O2sat 98 Temp98.4
PR 248msec QRS complex 170msec
o rS complex in V1 o Broad dominant S wave in V1 and V2 o "M" shaped QRS complex in aVL
Left Bundle Branch Block (LBBB)
Key Features of LBBB:
• Broad QRS >120 • Broad R waves in I, aVL, V5, and V6 (Depolarization moving toward these leads) o R waves can be monomorphic, "M" shaped, rS complex, or notched • Broad, dominant, S wave in V1 and V2 (Depolarization moving away from these leads)
+ Why is this important?
According to 2013 ACC/AHA guidelines NEW LBBB ALONE is no longer a STEMI equivalent and NOT a criteria for cath lab activation. However, as EM physicians we must recognize if ST elevation in the presence of LBBB (new or old LBBB) is due to infarction or not.
So how do you recognize this?!
Original Sgarbossa criteria: 1) ST-segment elevation ≥1 mm concordant (points in same direction) with the QRS complex in any lead (5 points) 2) ST-segment depression ≥1 mm in lead V1, V2, or V3 (3 points) 3) ST-segment elevation ≥5 mm discordant (opposite direction) with the QRS complex in any lead (2 points) (This finding is less specific than 1 or 2)
+ What should be your next step in mangement
If a patient has a score of ≥ 3 activate the cath lab for PCI or give thrombolytics
+ Additional resources
GREAT Amal Mattu video at the end explaining sgarbossa's criteria worth the ~20 min to watch! http://lifeinthefastlane.com/ecg-library/basics/sgarbossa/