Assoc Prof Harry Mond
December 17, 2024
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.
![](https://cdn.prod.website-files.com/675b0fb39c1b52376af55902/67604399fa4bb9ab066ef542_676043100307c198ef344bc0_image%2520(3).png)
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.
![](https://cdn.prod.website-files.com/675b0fb39c1b52376af55902/67604399fa4bb9ab066ef56a_67604345c8a1b0bbb87925e7_image%2520(4).png)
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?).
![](https://cdn.prod.website-files.com/675b0fb39c1b52376af55902/67604399fa4bb9ab066ef546_6760437d1118d519e6443449_image%2520(5).png)