Emergencies
Results:
Preexcitation Syndromes: Overview
Key Points: Pre-excitation means an accessory pathway allows atrial impulses to reach the ventricle without traversing the AV node, producing early ventricular activation. A delta wave is the defining ECG…
Wolff-Parkinson White (WPW) Syndrome
Key Points: Pattern vs syndrome: WPW pattern is ECG evidence of pre-excitation without symptoms. WPW syndrome is pattern plus symptomatic tachyarrhythmia (palpitations, syncope, “seizure”, aborted sudden cardiac arrest). PR interval…
Atrial Flutter 1:1 Conduction
Key Points: Rare, high-risk rhythm. 1:1 flutter can drive ventricular rates into the 240–320 bpm range and can rapidly cause hypotension, ischemia, or collapse. It often mimics VT. Ask “how…
WPW Syndrome and Pseudo-MI Patterns
Key Points: WPW alters ventricular depolarization, producing secondary repolarization abnormalities that can mimic or mask myocardial infarction. ST-segment deviation in WPW is often non-ischemic, driven by abnormal activation via the…
Atrial Fibrillation with WPW (Pre-excited AF)
Key Points: Pre-excited AF is the most dangerous WPW rhythm. It can deteriorate quickly to VF because the accessory pathway may conduct atrial impulses to the ventricle at extreme rates….
WPW with Antidromic SVT (Antidromic AVRT)
Key Points: Antidromic AVRT is an AV re-entrant tachycardia that conducts antegrade down the accessory pathway and returns retrograde through the AV node (or another pathway), producing a regular wide-complex…
WPW with Orthodromic SVT (Orthodromic AVRT)
Key Points: Orthodromic AVRT is the most common tachyarrhythmia in WPW and presents as a regular narrow-complex SVT that is indistinguishable from AVNRT during the tachycardia. Mechanism: antegrade conduction down…
The Life Savers: Critical ECG Pattern Hub
Key Points: Critical ECG patterns represent time-sensitive, life-threatening cardiac or systemic conditions that demand immediate recognition to prevent death or irreversible organ injury. These are the “can’t-miss” ECGs. Use this…
Baltimore City EMS ECGs: Pitfalls and Mimics (Part 2)
A 54-year-old man presents to the emergency department by EMS with acute shortness of breath. A prehospital ECG triggers a STEMI alert based on the computer interpretation. The tracing shows…
Baltimore City EMS ECGs: Pitfalls and Mimics (Part 1)
A 68-year-old man is brought to the emergency department by EMS with acute chest discomfort. The following prehospital ECG was obtained and shows concave ST elevation across multiple leads. The…
Three More ECG Pitfalls That Punish Anchoring Bias
A 51-year-old man with lung cancer presents with shortness of breath and tachycardia. The arrival ECG shows an S1Q3 pattern and seems to support a familiar diagnosis that would normally…
Bidirectional Ventricular Tachycardia (BiVT)
Key Points: BiVT is a regular wide-complex tachycardia with strict beat-to-beat alternation of QRS axis and/or bundle-branch pattern (often an approximately 180° frontal-plane axis flip). In adults, assume digoxin toxicity…
Four ECG Pitfalls That Punish Anchoring Bias
A 43-year-old woman with sharp left-sided chest pain and minimal cardiac risk factors has an initial ECG that is not diagnostic for STEMI. She looks stable, but one feature on…
Occlusion MI: STEMI Criteria & Beyond
Key Points: The ECG’s primary role in ACS is detecting acute coronary occlusion. Acute coronary occlusion myocardial infarction (OMI) is a time-critical diagnosis that requires immediate reperfusion. Time is myocardium….
STEMI (-) Occlusion MI: OMI Patterns
Key Points: Traditional STEMI criteria miss many acute coronary occlusions. A substantial proportion of true OMIs do not meet classic millimetric STEMI thresholds. OMI is a pathophysiologic diagnosis, not an…
Prolonged QT Interval: DDx
Key Points: The QT interval reflects the time it takes for total ventricular depolarization and repolarization (Q wave onset to T wave end). QT prolongation increases the risk of torsades…
Hypocalcemia
Key Points: Prolonged QTc is the hallmark ECG change in hypocalcemia, driven mainly by ST-segment prolongation with relatively normal T-wave shape. Hypocalcemia can increase arrhythmia risk, including TdP, but TdP…
STEMI in the Presence of Baseline ECG Abnormalities
Key Points: Baseline ECG abnormalities do not protect patients from occlusion MI. They increase miss rates because they distort the ST segment and T waves. The core question is not…
Lateral and High-Lateral STEMI: Criteria, Localization, and Pitfalls
Key Points: Lateral and high-lateral STEMI often present with subtle ST elevation and are commonly missed or labeled as nonspecific ST-T changes. Small-appearing ECG changes may represent true coronary occlusion…
Inferior STEMI: Criteria, RV Involvement, and Pitfalls
Key Points: Inferior STEMI is the most common STEMI subtype and is frequently complicated by right ventricular and posterior involvement. Inferior occlusion may present with classic ST elevation, subtle ischemic…
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