Neth Heart J (2017) 25:592–593 DOI 10.1007/s12471-017-0993-0

RHYTHM PUZZLE - QUESTION

A surprising finding after adenosine administration C. Timmermans1 · H. Wellens2

Published online: 26 April 2017 © The Author(s) 2017. This article is an open access publication.

The patient was a 22-year-old man with a 8-year history of episodes of a rapid heart rhythm. A 12-lead ECG during sinus rhythm (not shown) was normal. The ECG of Fig. 1 was recorded in the catheterisation room after adenosine administration and shows sinus rate slowing, changes in QRS configuration and an episode of complete AV block. Thereafter AV conduction resumes. Can you explain the QRS changes in beats 3 to 6, and those in beats 7 to 11?

 C. Timmermans

[email protected] 1

Department of Cardiology, Maastricht University Medical Center, Maastricht, The Netherlands

2

21 Henric van Veldekeplein, Maastricht, The Netherlands

Answer You will find the answer elsewhere in this issue. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http:// creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Neth Heart J (2017) 25:592–593

Fig. 1 Twelve-lead ECG after adenosine administration during sinus rhythm

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