Back to Harry's Corner

What Do You Think 14

Harry's Corner /

ECG Challenges

Author

Assoc Prof Harry Mond

Published

March 12, 2025

Download a free PDF copy!

To receive a free PDF copy of The Fundamentals of Electrocardiograph Interpretation by Harry Mond, subscribe to his email blog by entering your email address below.

Thank you! Your submission has been received!

Oops! Something went wrong while submitting the form.

Purchase the textbook

Purchase a hard cover or paperback copy of The Fundamentals of Electrocardiograph Interpretation by Harry Mond on Amazon.

Purchase textbook

78-year old deep sea diver with symptomatic sick sinus syndrome and an implanted pacemaker, programmed DDDR with an AV delay of 400 ms.

ECG reported as abnormal pacemaker function.

What do you think?

Try to diagnose each complex and then put it together.

Atrial pacing (Ap) and ventricular sensing (Vs) at a rate of 60 bpm (1000ms).
Ventricular ectopic (red highlight) with retrograde conduction (red arrow As).
After an AV delay of 400 ms, there is a ventricular stimulus artefact ((first blue arrow) and ventricular pacing (Vp)again with retrograde conduction setting up an endless loop, although not a tachycardia (rate ~ 90 bpm), because of the long AV delay (yellow highlight and blue arrows).

Pacemaker mediated rhythm (tachycardia) precipitated by a ventricular ectopic.

‍