What question did this study set out to answer?

To define the electrophysiological patterns of initial ventricular septal activation across normal cardiac conduction, complete left bundle branch block, and incomplete left bundle branch block.

September 1, 1980CirculationOpen Access

Initial ventricular activation in left-sided intraventricular conduction defects.

View Full Paper

Ask AI

Bookmark

Why the study?

How does ventricular septal activation change during rate-related left bundle branch block?

Population

9 patients with ECG evidence of rate-related left bundle branch block (LBBB)

Comparison

Electrophysiological study using His bundle… vs Baseline normal conduction before rate increase

Design

Case_series

Authors

DCDavid S. CannomElectrophysiology MWMilford G. WymanUniversity of Southern California BGBruce N. GoldreyerUniversity of Southern California

Discussion

Member takes

Implication

Variable septal activation in rate-related LBBB warrants caution interpreting HV intervals; leaves open relevance for conduction-system pacing strategies.

Key Points

To define the electrophysiological patterns of initial ventricular septal activation across normal cardiac conduction, complete left bundle branch block, and incomplete left bundle branch block.
Evaluated 9 patients with electrocardiographic evidence of rate-related left bundle branch block (LBBB).
Recorded His bundle electrograms, right ventricular apex electrograms, and vectorcardiograms while heart rates were increased to induce conduction block.
In group 1 (n=5; complete LBBB), block induction reversed initially normal septal activation and lengthened HV intervals by 10–30 msec without altering the H-RVA interval.
In group 2 (n=4; incomplete LBBB), septal activation was reversed at baseline despite normal QRS duration (90–100 msec), and rate-induced LBBB widened the QRS complex without altering HV or H-RVA intervals.

Structured PICO

How does ventricular septal activation change during rate-related left bundle branch block?

Population

9 patients with ECG evidence of rate-related left bundle branch block (LBBB)

Intervention

Electrophysiological study using His bundle electrograms, electrograms from the right ventricular (RV) apex, and vectorcardiograms recorded as heart rate was increased to produce LBBB

Comparator

Baseline normal conduction before rate increase

Outcome

Ventricular septal activation patterns, HV intervals, and H-RVA intervalssurrogate

The study defines distinct ventricular septal activation patterns in complete and incomplete rate-related left bundle branch block, showing both are markedly different from normal conduction.

Cite This Study

Cannom et al. (1980) studied this question.

synapsesocial.com/papers/6a0e2ade358c8502d7d097e2 https://doi.org/10.1161/01.cir.62.3.621

View Full Paper

Ask AI

Bookmark

Implication

Variable septal activation in rate-related LBBB warrants caution interpreting HV intervals; leaves open relevance for conduction-system pacing strategies.

Initial ventricular activation in left-sided intraventricular conduction defects.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Initial ventricular activation in left-sided intraventricular conduction defects.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider