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Case Reports
. 2017 Jul;22(4):e12423.
doi: 10.1111/anec.12423. Epub 2016 Dec 23.

A narrow QRS tachycardia and cannon A waves: What is the mechanism?

Hussam Ali  1 , Gianluca Epicoco  1 , Guido De Ambroggi  1 , Pierpaolo Lupo  1 , Sara Foresti  1 , Riccardo Cappato  2
Affiliations
Case Reports

A narrow QRS tachycardia and cannon A waves: What is the mechanism?

Hussam Ali et al. Ann Noninvasive Electrocardiol. 2017 Jul.

Abstract

Regular narrow QRS tachycardia, particularly if well-tolerated, is usually considered a "benign" arrhythmia of a supraventricular origin. This case concerns an 82-year-old male with ischemic heart disease who presented with recurrent episodes of a narrow QRS tachycardia that was initially diagnosed and treated as atrial tachyarrhythmia. However, careful physical examination and ECG analysis established the correct diagnosis, and the patient was managed appropriately. Remarkably, the observation of irregular cannon A waves, and Lewis lead recording, confirmed atrioventricular dissociation during tachycardia and indicated its underlying mechanism.

Keywords: Lewis lead; atrioventricular dissociation; cannon A waves; ventricular tachycardia.

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Conflict of interest statement

None.

Figures

Figure 1
Figure 1
Twelve‐lead ECG of the clinical narrow QRS tachycardia (NQT)
Figure 2
Figure 2
Twelve‐lead ECG during sinus rhythm (SR) showing 1st degree AV block and a premature ventricular complex
Figure 3
Figure 3
Lewis lead during narrow QRS tachycardia (NQT) showing AV dissociation (the arrows indicate P waves)
Figure 4
Figure 4
Atrial, ventricular, and shock recordings from the implanted defibrillator showing a ventricular tachycardia (VT) episode that was terminated successfully by anti‐tachycardia pacing
See this image and copyright information in PMC

References

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    1. Lewis, T. (1931) Auricular fibrillation In Lewis T. (Ed.), Clinical electrocardiography (5th ed., pp. 87–100). London, UK: Shaw and Sons.
    1. Tung, M. K. , & Healy, S. (2016). Images in clinical medicine. Cannon A waves. The New England Journal of Medicine, 374, e4. - PubMed

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