This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by ROSENBAUM, M. B. Articles by LAZZARI, J. O. Search for Related Content PubMed PubMed Citation Articles by ROSENBAUM, M. B. Articles by LAZZARI, J. O.

(Circulation. 1969;40:79.)
© 1969 American Heart Association, Inc.

---

Wenckebach Periods in the Bundle Branches

MAURICIO B. ROSENBAUM M.D.¹; GERARDO J. NAU M.D.¹; RAUL J. LEVI M.D.¹; M. SUSANA HALPERN M.D.¹; MARCELO V. ELIZARI M.D.¹; JULIO O. LAZZARI M.D.¹

¹ From the Services of Cardiology of Salaberry Hospital and Argerich Hospital, Buenos Aires, Argentina.

Two cases of intermittent bundle-branch block in which Wenckebach periods could be directly visualized are reported. The conduction ratios were either 3:2 or 4:3, as are commonly seen in cases of the Wenckebach phenomenon of atrioventricular (A-V) conduction. Other groups of beats apparently showing 3:1 and 4:1 bundle-branch block were interpreted as indicating incompletely concealed Wenckebach periods in the bundle branches, with actual conduction ratios of 3:2 and 4:3, respectively.

Three prerequisites are necessary for the occurrence of either direct or incompletely concealed Wenckebach periods in the bundle branches: (1) The opening beat should be normally conducted (in the affected bundle branch); (2) the second beat should be conducted with a delay of no more than 0.04 to 0.06 sec; (3) the damaged bundle branch should not be activated retrogradely in the closure beat.

Wenckebach periods in the bundle branches may be completely concealed if the conduction delay lasts more than 0.04 to 0.06 sec in the opening beat. In cases of bilateral bundle-branch block, Wenckebach periods in the bundle branches may be indirectly visualized through changes in the A-V conduction.

Key Words: Concealed conduction in the bundle branches • Trifascicular blocks • Bilateral bundle-branch block

This article has been cited by other articles:

				R. R. Kraeger, J. A. Lagos, and H. B. Barner Long Term Evaluation of Allogenic Veins as Arterial Grafts Vascular and Endovascular Surgery, March 1, 1976; 10(2): 121 - 127. [PDF]