Publish in this journal
Journal Information
Vol. 71. Issue 1.
Pages 46 (January 2018)
ECG Contest
DOI: 10.1016/j.rec.2017.05.018
Full text access
ECG, January 2018
ECG de enero de 2018
Pasquale Creaa,
Corresponding author

Corresponding author:
, Emmanuele Soracia, Raffaella Mallamaceb
a Department of Clinical and Experimental Medicine, Cardiology Unit, University of Messina, Messina, Italy
b Department of Clinical and Experimental Medicine, Anesthesiology and Intensive Care Unit, University of Messina, Messina, Italy
Related content
Rev Esp Cardiol. 2018;71:11610.1016/j.rec.2017.05.019
Pasquale Crea, Emmanuele Soraci, Raffaella Mallamace
This item has received
(Daily data update)
Article information
Full Text
Download PDF
Figures (1)
Full Text

A 55-year-old woman was admitted to the emergency room for palpitations. Analysis of the ECG (Figure, panel A) showed a regular tachycardia (190 bpm) with alternation of narrow and wide QRS complexes (right bundle branch block [RBBB] morphology). The R-R intervals were stable. Narrow QRS beats showed a pseudo-r’ wave in V1, suggesting slow-fast atrioventricular nodal re-entry tachycardia. The patient was hemodynamically stable (blood pressure 130/80mmHg). Vagal maneuvers were ineffective. Adenosine was administered in intravenous bolus (6mg), obtaining sinus rhythm restoration (Figure, panel B, in lead II a clear positive P wave was observed). The ECG after cardioversion showed sinus tachycardia 140 bpm. Alternation of narrow and wide QRS complex persisted. Curiously, after some minutes, this singular behavior ceased, along with heart rate slowing (120 bpm, Figure, panel C). The final ECG showed sinus tachycardia with constant RBBB.


How do you explain alternation of narrow and wide QRS complexes in panel A and B?

  • 1)

    Bigeminy ventricular extrasystoles with constant fusion beats.

  • 2)

    2:1 RBBB.

  • 3)

    Phase 4 RBBB.

  • 4)

    RBBB, supernormal conduction and linking phenomenon.

Suggest a diagnosis to this ECG Contest at The answer will be published in the next issue (February 2018). #EKGchallenge.

Copyright © 2017. Sociedad Española de Cardiología
Revista Española de Cardiología (English Edition)

Subscribe to our newsletter

Article options
es en

¿Es usted profesional sanitario apto para prescribir o dispensar medicamentos?

Are you a health professional able to prescribe or dispense drugs?