This week we had a Holter monitor recording reported as complete heart block. For obvious reasons this can be a serious diagnosis, but the reporting cardiologist felt it was Wenckebach sequences and requested a review.
Wenckebach sequences almost always have a generous pause at the termination of a sequence.
In the above example, the blocked P wave extends the R to R interval from about 1000 ms to 1900 ms.
Sometimes this interval is shorter when the preceding PR interval becomes very long and the blocked P wave occurs immediately following the previous T wave.
Can the pause disappear?
In the following tracing, there is no pause because the blocked P wave is concealed within the QRS of the previous beat. which has a very long PR interval (or is it a junctional escape beat?).
Can you see the confusion with complete heart block?
This is surely a “rebel without a pause”.
Assoc Prof Harry Mond
In 49+ years as a practicing cardiologist, Assoc Prof Harry Mond has published 260+ published manuscripts & books. A co-founder of Cardiac Monitoring Service, he remains Medical Director and oversees 500K+ heart studies each year.
Download his full profile here.