Metabolic
Results:
Short QT Interval: DDx
Key Points: Short QT Interval: A QT interval is considered short when the corrected QT (QTc) interval is less than 350 ms. A short QT interval on the ECG can…
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…
Hypercalcemia
Key Points: Shortened QTc interval is the hallmark ECG clue in hypercalcemia, primarily due to a shortened ST segment duration. Hypercalcemia can mimic acute STEMI on ECG (pseudoinfarction pattern due…
Himalayan T Waves
Key Points Tall, broad-based T–U fusion that looks like a mountain peak, usually from severe hypokalemia; think high torsades risk until proven otherwise. Hallmark is prolonged repolarization: QT appears long…
Ventricular Tachycardia (VT) Mimics
Key Points: Initial Assumption: Any wide (QRS >120 ms), regular tachycardia should be considered ventricular tachycardia (VT) until clearly proven otherwise. VT Characteristics: VT generally has a ventricular rate of…
Osborn (J) Wave: Basics
Key Points An Osborn wave is a notch or slur at the J point that becomes more prominent as core temperature falls. Most visible in inferolateral and precordial leads; can…
Severe Hypothermia
Key Points Severe hypothermia causes rate- and temperature-dependent ECG changes that signal high arrhythmia risk. Recognition guides safe rewarming and prevents iatrogenic VF. Osborn (J) waves may appear and typically…
BRASH Syndrome
Key Points BRASH is a synergistic spiral: bradycardia, renal failure, therapeutic AV-nodal blockade, shock, and hyperkalemia. The signature clue is disproportionate brady-shock despite only modest potassium elevation. Do not be…
Hypermagnesemia
Key Points ECG red flags: Bradycardia, PR/QRS/QT prolongation, flattened P, peaked T, → AV block/asystole at higher levels. Neuromuscular: Hyporeflexia → weakness → respiratory depression → coma. Immediate countermeasure (severe/symptomatic):…
U Wave: Basics
Key Points Definition and origin: The U wave is a small deflection following the T wave, best seen in V2–V3. It likely reflects late ventricular repolarization or Purkinje repolarization. Normal…
Metabolic Emergencies
Key Points A Simple Yet Powerful Tool: With just a piece of paper and some ink, the ECG can be the earliest clue to life-threatening metabolic disease when labs are…
Altered Mental Status Emergencies
Key Points Always get a 12-lead ECG in altered or confused patients. The ECG is a great triage and risk stratification tool and can reveal reversible, life-threatening causes when history…
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…
STEMI vs Severe Hyperkalemia: DDx
Key Points The ECG Chameleon: Severe hyperkalemia can produce ST segment elevations, wide QRS complexes, and conduction delays that closely resemble STEMI or ventricular tachycardia. Early misinterpretation can lead to…
Hyperkalemic Periodic Paralysis (Impressive Syndrome)
Key Points What It Is: A rare autosomal dominant sodium channelopathy that leads to episodic muscle weakness or paralysis in the setting of elevated serum potassium. Named after “Impressive,” the…
Hypokalemic Periodic Paralysis
Key Points Definition: A rare ion channelopathy that causes sudden, reversible episodes of symmetric flaccid paralysis triggered by low serum potassium. It may be inherited or secondary to thyrotoxicosis or…
Hypomagnesemia
Key Points Prolonged QT & PR Intervals significantly increase the risk of torsades de pointes and other arrhythmias. Atrial & Ventricular Ectopy is common; can progress to life-threatening ventricular tachycardia….
Hyperkalemia Emergencies
Key Points Severe Hyperkalemia Mimics Several Life-Threatening Conditions: Hyperkalemia can produce a wide range of ECG abnormalities that resemble unstable brady and tachy arrhythmias, STEMI, and can also cause pacemaker…
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