Bundle branch block. Demonstration of the incomplete nature of some "complete" bundle branch and fascicular blocks by the extrastimulus technique

Delon Wu, Pablo Denes, Ramesh Dhingra, Kenneth M. Rosen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

The incomplete nature of some electrocardiographic "complete" bundle branch and fasclcular blocks is demonstrated using the atrial extrastimulus technique. Patient 1, with a QRS pattern of "complete" left bundle branch block, manifested a QRS pattern of right bundle branch block at a shorter coupling interval, indicating that the left bundle could conduct. Patient 2, with a QRS pattern of right bundle branch block and "complete" left anterior hemiblock, manifested a pattern of left posterior hemiblock at a shorter coupling interval, indicating that the left anterior fascicle could conduct. Patient 3, with a normal QRS complex, showed left bundle branch block at shorter coupling intervals and then a pattern of right bundle branch block as the coupling interval was further decreased, indicating that functional left bundle branch block was incomplete. This demonstration of partial bundle branch block depends on a discordance of conduction time and refractory period, the bundle or fascicle with depressed conduction (incomplete block) having a shorter refractory period than the more normally conducting bundle or fascicle. This discordance may be related to the development of trifascicular block in patients with bifascicular block and a normal H-V interval. It is a predisposing factor in the complex patterns of aberrant conduction seen during supraventricular tachyarrhythmias with varying cycle lengths.

Original languageEnglish (US)
Pages (from-to)583-589
Number of pages7
JournalThe American journal of cardiology
Volume33
Issue number5
DOIs
StatePublished - May 6 1974

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Fingerprint Dive into the research topics of 'Bundle branch block. Demonstration of the incomplete nature of some "complete" bundle branch and fascicular blocks by the extrastimulus technique'. Together they form a unique fingerprint.

Cite this