It is well known that primary percutaneous coronary intervention (PPCI) is the gold standard in STEMI treatment and that decreased door-to-balloon time has better patient outcomes. Guidelines recommend that the interval between arrival at the hospital and intracoronary balloon inflation (door-to-balloon time) should be 90 minutes or less.
ECG interpretation is one of the most important skills to master as an emergency physician, and its interpretation can be very complex and frustrating. ECG manifestations can be very subtle, and sometimes the earliest and only ECG change seen will be reciprocal changes alone. To further complicate this, many patients have the atypical symptoms of nausea/vomiting, weakness, or shortness of breath and not chest pain.
Brugada Syndrome is an abnormal ECG (Right Bundle Branch Block Pattern with coved ST elevation over the right precordial leads of V1-V3), which leads to ventricular fibrillation (VF) and sudden cardiac death (SCD) in patients with structurally normal hearts. It has been recognized as a clinical entity since 1992. Why should all ED physicians know about this entity? Although a rare syndrome, it is often mistaken as a STEMI and more importantly the clinical spectrum can be asymptomatic to SCD.
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Torsades de pointes is a polymorphic form of ventricular tachycardia. Why does this occur? What does it characteristically look like? Why is this an important form of ventricular tachycardia to differentiate from the more classic monomorphic ventricular tachycardia? View this short 9 minute video on QT intervals and Torsades de Pointes.
Augmented leads (aVR, aVF, and aVL) were developed to derive more localized information looking at the right, lower, and left part of the heart respectively. Specifically, lead aVR obtains information from the right upper side of the heart. It also gives reciprocal information on the left lateral side of the heart, which is already covered by leads aVL, I, II, V5, and V6. This is the main reason lead aVR has become forgotten.
Wellen’s Syndrome was first described in 1982 in which 75% of patients with t wave inversions in V2-V4 went on to have an acute myocardial infarction (MI). This was again repeated in 1989, and showed that all patients with this morphology had >50% LAD stenosis. The incidence in the United States is about 10-15%.
You are handed an ECG for a 50 year old man with moderate chest pain for 2 hours now and no associated symptoms typical for ACS, PE, aortic dissection, or any other red flags of chest pain. He has no prior ECG’s on file.
Image courtesy of Dr. Steve Smith at HQMedEd-ecg.blogspot.com
Here are some great literature-based pearls compiled by Dr. Jason West (@JWestEM), an EM resident from Jacobi/Montefiore.
Adapted from [1–7]
Go to ALiEM (PV) Cards for more resources.
Furthermore, there is a formula to differentiate early repolarization vs STEMI, per Dr. Smith’s publication6:
(1.196 x STE60V3) + (0.059 x QTc) – (0.326 x RA V4)
A result of > 23.4 is predictive of a LAD occlusion causing a STEMI, rather than early repolarization.
P.S. The above ECG image shows early repolarization.