Scenario: A 78-year-old male is brought to the emergency department by his family, who states that he has been acting “very tired” for several days. The patient has a history of coronary artery disease, hypertension, and diabetes. The patient is lethargic and hypotensive (80/40), the radial pulse is thready and irregular, and he is jaundiced. The patient’s current medications include aspirin, metoprolol, lisinopril, and metformin. Notably, the family states that the patient has not been urinating for more than 1 week. Below is the initial ECG rhythm strip in lead II.

Sinus arrest with atrial (beats 2,4,6) and junctional escape beats (1,3,5)

The conduction system is designed so that if the sinoatrial (SA) node fails, an escape rhythm from a lower pacemaker site occurs. Escape rhythms typically originate from the atrioventricular (AV) junction at 40 to 60 beats/min or the Purkinje system at...

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