Emergencies
Results:
Inverted U Waves
Key Points Definition: A negative deflection after the T wave (a true U wave) that is ≥0.5 mm deep in a lead where the T wave is upright. Why it…
STEMI vs Artifact: DDx
Key Points: Not all ST elevation is ischemia. The most common mimics at the point of care are atrial activity riding on the ST segment, motion or lead artifact, early…
VT vs SVT with Aberrancy: DDx
Key Points ECG alone cannot reliably distinguish VT from SVT-aberrancy in many cases. Use ECG features to rule in VT, not to exclude it. Default: treat regular WCT as VT…
RV Outflow Tract Tachycardia (RVOT VT)
Key Points Idiopathic monomorphic VT arising from the right ventricular outflow tract. Most patients have no structural heart disease; catecholamine and cAMP-mediated triggers are common. Classic ECG pattern: LBBB morphology…
Hypokalemia
Key Points: Hypokalemia slows ventricular repolarization and alters the T–U complex before it triggers arrhythmias. Progressive pattern: T-wave flattening → prominent U waves → T–U fusion with apparent QT prolongation;…
Hypokalemia Emergencies
Key Points: Severe hypokalemia can produce dramatic ECG changes that may be mistaken for acute coronary syndromes. It can also precipitate life-threatening arrhythmias, including torsades de pointes and ventricular tachyarrhythmias…
Understanding ECG Artifacts
Key Points Artifacts = non-cardiac signals that distort or obscure true ECG. They come from the patient, leads/equipment, or the environment. Clues to artifact: lacks a physiologic pattern, varies beat-to-beat…
Fascicular Ventricular Tachycardia (Idiopathic Left Fascicular VT)
Key Points Idiopathic reentrant VT arising within the left Purkinje system, most often the left posterior fascicle. Patients are usually young and lack structural heart disease. Signature ECG: RBBB-like morphology…
Opiate Toxicity
Key Point Opioid overdose causes life-threatening respiratory depression leading to hypoxia, altered mental status, bradycardia, hypotension, and potentially death. While most cardiovascular effects are secondary to hypoxia, methadone toxicity uniquely…
Methamphetamine Toxicity
Key Point Methamphetamine is a powerful sympathomimetic that causes a massive catecholamine surge, it can result in life-threatening cardiovascular and neurologic complications. Toxicity can present with MI, arrhythmias, stroke, hypertensive…
Beta-Blocker and Calcium Channel Blocker Toxicity
Key Point BBs and CCBs are widely prescribed but overdoses can cause life-threatening bradycardia, AV block, hypotension, and shock. Differentiating between them is important, but both require early recognition, aggressive…
Cocaine Toxicity
Key Point Cocaine is a powerful sympathomimetic with profound cardiovascular (CV) effects. Even recreational or first-time use can precipitate life-threatening complications, including myocardial infarction (MI), stroke, arrhythmias, and aortic dissection….
Slow Ventricular Tachycardia (VT)
Key Points Definition: Slow ventricular tachycardia is defined as a wide complex tachycardia with a ventricular rate between 100–120 bpm. Distinction: Typical sustained VT usually exceeds 120 bpm. When encountering…
R-on-T Phenomenon
Key Points Definition: The R on T phenomenon occurs when an ectopic impulse (often a PVC or cardioversion shock) falls on the T wave of the preceding beat. Mechanism: Interrupting…
Right Ventricular STEMI: Criteria & Pitfalls
Key Points: RV involvement accompanies up to ~40% of inferior STEMIs; isolated RV infarction is uncommon but high-impact when missed. Think RV MI when inferior STEMI is present and you…
Toxicologic Emergencies
Key Points: ECG as a Critical Diagnostic Tool: In toxicology, the ECG is often the first and most reliable clue. Early recognition of drug-induced conduction disturbances or arrhythmias can guide…
Terminal QRS Distortion: OMI Pattern
Key Points: What it is: In V2 or V3, there is no S wave (the R does not descend below the PQ baseline) and no J wave (no notch/slur at…
Digoxin Toxicity
Key Points Narrow therapeutic window: Small dosing errors or renal decline can push serum digoxin above the safe range. Excess automaticity + AV block: Toxicity increases atrial and ventricular irritability…
Right Axis Deviation + ST Elevation: DDx
Key Points RAD combined with ST-segment elevation (STE) is an uncommon but high-risk finding. While STE often suggests acute coronary occlusion, this pattern rarely reflects classic STEMI. Several non-ischemic conditions…
Pseudonormalization of T Waves
Key Points Definition: Pseudonormalization is the apparent normalization of previously inverted T waves, often signaling reocclusion of a coronary artery that had recently reperfused. Mechanism: During reperfusion, ischemic T wave…
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