By Forrest Munden — 21-Year Firefighter Paramedic & NREMT Tutor
EMT Tutor Podcast · Paramedic (ALS) · 13:44
Show notes
This podcast is written by Forrest Munden and sponsored by Munden Interactive. I train paramedics and EMTs to pass the National Registry. A paramedic-level episode on bundle branch blocks, the Sgarbossa criteria, and STEMI mimics for the National Registry exam. It covers when a QRS is wide, the AHA ECG-standard criteria for right versus left bundle branch block, memory aids like WiLLiaM MaRRoW, why a left bundle branch block hides a STEMI, the original Sgarbossa criteria (5-3-2, and you need 3) and Smith's modified rule, why a new LBBB alone is not a STEMI equivalent under the 2025 AHA/ACC guideline, paced rhythms, the patterns that fake a STEMI (pericarditis, LVH, early repolarization, Brugada, high potassium, takotsubo), and the warning patterns that hide one (Wellens and de Winter). For a written study guide, see EMS Notes, an EMT and paramedic study guide at emsnotes.com, also written by Forrest Munden. Education, not medical direction; follow your local protocols.
What this episode covers
- When a QRS is wide: 110 ms abnormal, 120 ms or more for a complete block (AHA ECG standards)
- Right bundle branch block criteria and the "rabbit ears"
- Left bundle branch block criteria and discordant ST-T changes
- Study aids: WiLLiaM MaRRoW and the turn signal
- Why a left bundle hides a STEMI (and why RBBB does not change the ST criteria)
- The original Sgarbossa criteria: 5-3-2, and you need 3
- Smith's modified rule: the ST/S ratio
- Why a new LBBB alone is not a STEMI equivalent (2025 AHA/ACC ACS guideline)
- Paced rhythms
- STEMI mimics: pericarditis, LVH, early repolarization, Brugada, high potassium, takotsubo
- Patterns that hide an occlusion: Wellens and de Winter
Want it in writing? Study along with EMS Notes, an EMT and paramedic study guide at emsnotes.com, also written by Forrest Munden.
This is education, not medical direction. Follow your local protocols and your medical director.
More episodes: EMT Tutor Podcast
Learn more at https://emttutor.com
© 2026 Forrest Munden. All rights reserved.
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