ISSN: 1885-5857 Impact factor 2023 7.2
Vol. 71. Num. 3.
Pages 207 (March 2018)

Ecg contest
Response to ECG, February 2018

Respuesta al ECG de febrero de 2018

Pablo Elpidio García-GranjaabMaría Sandín FuentesabEmilio García-Moránab
Rev Esp Cardiol. 2018;71:11510.1016/j.rec.2017.10.020
Pablo Elpidio García-Granja, María Sandín Fuentes, Emilio García-Morán

Options

This was a case of ventricular extrasystoles superimposed on sinus rhythm with P waves blocked by concealed and incomplete penetration of extrasystoles in the bundle of His1,2 (correct answer, response 2). Figure shows the surface and bundle of His electrocardiograms (A, atrium; H, His; V, ventricle). The patient is in sinus rhythm and the P waves have a relatively constant cycle duration (924ms) and typical and stable morphology (response 3 and 4, incorrect). Capture of the ventricular extrasystole by the bundle of His leads to suprahisian block of the following atrial pulse (incomplete penetration). The suprahisian block then enables atrioventricular node (AVN) recovery and improved suprahisian conduction in the following pulse (shortening of the A-H interval from 171 to 126ms). There is no intrinsic defect in conduction, but rather a physiological response of the AVN to incomplete penetration of a ventricular extrasystole (response 1, incorrect).

Figure
(0.3MB).

.

References
[1]
M.E. Josephson.
Miscellaneous phenomena related to atrioventricular conduction.
Clinical cardiac electrophysiology. Techniques and interpretations, 5a ed., Wolters Kluwer Health, pp. 144-147
[2]
R. Langenford.
Concealed A-V conduction: the effect of blocked impulses on the formation and conduction of subsequent impulses.
Am Heart J., (1974), 35 pp. 542
Copyright © 2017. Sociedad Española de Cardiología
Are you a healthcare professional authorized to prescribe or dispense medications?