Challenge Archive

human · beginner · A 68-year-old comes to urgent care with two days of palpitations, mild shortness of breath, and fatigue. Blood pressure is 128/76 and the patient is alert. A lead II rhythm strip recorded at 25 mm/s is shown; the average ventricular rate is about 110 bpm and the QRS complexes are narrow. Based on the tracing, what is the rhythm?

human · beginner · A 58-year-old presents to the clinic reporting occasional "skipped beats." The 12-lead tracing shows an underlying regular rhythm at about 78 beats per minute with upright P waves before most QRS complexes. Three times on the strip, an early, wide (>140 ms), bizarre-looking QRS appears with no P wave in front of it and with the T wave pointing opposite the QRS; each is followed by a brief pause before the next normal beat. No two early beats occur in a row. What is the rhythm?

human · beginner · A 58-year-old man is seen in clinic for occasional "skipped beat" sensations. His telemetry strip shows an underlying regular rhythm at about 78 beats per minute, interrupted three times by an early beat. Each early beat has a narrow QRS identical in shape to the others, and just in front of it is a small upright bump that sits differently from the P waves of the regular beats. The pause after each early beat is short, and the underlying timing resumes without a full missed cycle. What is the rhythm?