A 51-year-old truck driver presents to the ED after a brief syncopal episode at a rest stop. It is the middle of summer, his truck’s air conditioning is not working,…
A 69-year-old woman presenting with sepsis gets the following ECG for tachycardia while febrile and shivering. The baseline is poor, atrial activity is difficult to identify, and the computer interpretation…
A 72-year-old man undergoes a prehospital 12-lead ECG. The tracing appears to show ST segment elevation in leads III, aVF, and aVR, raising concern for an inferior STEMI or high-risk…
A 72-year-old man is brought to the ED after witnessed cardiac arrest. Bystander CPR was started quickly, EMS found a nonshockable rhythm, epinephrine was given, and ROSC was achieved. Forty…
Key Points: The J point is the junction between the end of the QRS complex and the beginning of the ST segment. It is a location, not a separate waveform….
A 72-year-old man is brought to the ED after a witnessed out-of-hospital cardiac arrest. Bystander CPR is started quickly, EMS finds a non-shockable rhythm, and ROSC is achieved after one…
Key Points: A QRS duration greater than 120 ms reflects delayed or abnormal ventricular depolarization. A wide QRS may be chronic and benign in context, or it may be the…
A 71-year-old man presents with shortness of breath, and his ECG is initially read as a junctional rhythm. On later review, it is even mistaken for atrial fibrillation. But the…
Key Points: Junctional rhythms arise from the AV junction, usually the AV node or proximal His bundle, when the sinus node slows, fails, or impulses do not reach the ventricles…
An 81-year-old woman presents with lightheadedness and marked bradycardia. Her ECG shows more P waves than QRS complexes, but the mechanism is not immediately clear. The key question is whether…
Key Points: Don’t trust the ECG machines automated interpretation. Confirm the rhythm yourself. Start with the ventricles (R–R pattern), then the atria (P waves), then the AV relationship (PR behavior/P:QRS)….
Key Points: Never accept the machine’s rate blindly. Confirm it yourself as ECG computer interpretations are frequently inaccurate. Verify paper speed and gain first (default 25 mm/s, 10 mm/mV). Name…
A 60-year-old man presents with chest pain that seems a little better after belching, but his clinician is not reassured. The initial ED ECG shows subtle ST-segment abnormalities, the computer…
Key Points: Use a consistent ECG routine. In acute care, a repeatable approach reduces misses and helps you recognize dangerous patterns faster. Prioritize life threats first. Instability, malignant rhythms, occlusion…
Key Points: The Bix Rule is a bedside ECG clue for atrial flutter with 2:1 conduction. If an apparent “P wave” sits exactly halfway between 2 QRS complexes in a…
A 53-year-old man presents with palpitations and lightheadedness. The following ECG is obtained on arrival and appears very rapid and irregular with changing QRS morphologies. He starts showing signs of…
A young man with recurrent palpitations presents to the emergency department hemodynamically stable during an episode. The arrival ECG shows a wide complex, regular tachycardia and the computer interpretation calls…
Key Points: Appropriate discordance refers to the expected secondary ST segment and T wave pattern seen with abnormal ventricular depolarization, especially LBBB and ventricular-paced rhythm. The ST segment and T…
Key Points: Read the QRS before you read the ST segment or T wave. Ventricular depolarization shapes repolarization. Narrow QRS usually reflects normal His-Purkinje conduction. Wide QRS suggests abnormal ventricular…
A critically ill 38-year-old man presents hypotensive, pale, and diaphoretic with abdominal pain and rectal bleeding. Upright chest X-ray shows free air under the diaphragm, and the patient is headed…