Appropriate or inappropriate ICD shock; what is the post-shock rhythm?

Netherlands Heart Journal, May 2017

B. M. van Gelder, B. ter Burg, F. A. L. E. Bracke

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://link.springer.com/content/pdf/10.1007%2Fs12471-017-1000-5.pdf

Appropriate or inappropriate ICD shock; what is the post-shock rhythm?

Appropriate or inappropriate ICD shock; what is the post-shock rhythm? B. M. van Gelder 0 B. ter Burg 0 F. A. L. E. Bracke 0 0 Department of Electrophysiology, Catharina Hospital , Eindhoven , The Netherlands - At first sight, this may seem an appropriate shock for ventricular fibrillation, followed by conversion to sinus rhythm. However, the abrupt change in morphology of the RV electrogram with extreme short fibrillation sense (FS) intervals below 200 ms is not suggestive of ventricular fibrillation. The intervals are also comparable with the atrial sense (AS) and atrial sensing in the blanking period (Ab) intervals in the atrial channel. These observations suggest that the sensed arrhythmia in the ventricular channel is not ventricular fibrillation, but sensing of atrial fibrillation. This Fig. 1 X-ray right anterior oblique view showing an apical lead position at implant (left panel) and displacement into the right atrium in the post-shock X-ray (right panel) observation can only be explained by a displacement of the ventricular lead towards the right atrium. Review of the X-rays, which at implant showed a normal RV apical position of the shock lead (Fig. 1, left panel), showed migration of the lead into the right atrium in the post-shock X-ray (Fig. 1, right panel). It is therefore clear that the shock therapy was inappropriate. The post-shock right atrial electrogram showed the simultaneous termination of atrial fibrillation, which suggests ventricular pacing. However, the ventricular pace pulse is actually stimulating the atrium. This is proven by the coinciding atrial activation on the atrial lead (Fig. 2). Fig. 2 After stabilisation, the right atrial electrogram shows atrial stimulation by the ventricular lead (Vp) with subsequent antegrade conduction to the ventricle as indicated by the ventricular far-field electrogram (arrows) in the right atrial electrogram (As) The effective atrial stimulation from the ventricular pace pulse is a further confirmation of the ventricular lead dislocation. The far-field R wave signal in the atrial channel indicates subsequent antegrade conduction to the ventricle (Fig. 2). Conflict of interest B.M. van Gelder provides training and education for St Jude Medical, the Netherlands and is clinical advisor for 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.


This is a preview of a remote PDF: https://link.springer.com/content/pdf/10.1007%2Fs12471-017-1000-5.pdf

B. M. van Gelder, B. ter Burg, F. A. L. E. Bracke. Appropriate or inappropriate ICD shock; what is the post-shock rhythm?, Netherlands Heart Journal, 2017, 1-2, DOI: 10.1007/s12471-017-1000-5