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Ventricular septal motion and left ventriclular dimensions during abnormal ventricular activation
The American Journal of Cardiology
|May 4, 1977
Summary
Right ventricular pacing alters septal motion and reduces left ventricular dimensions, with patterns varying by pacing site and rate. These changes mimic left bundle branch block, depending on activation sequence.
Area of Science:
- Cardiology
- Echocardiography
- Electrophysiology
Background:
- Ventricular activation sequence influences cardiac mechanics.
- Understanding abnormal septal motion is crucial for diagnosing conduction abnormalities.
Purpose of the Study:
- To investigate the impact of abnormal ventricular activation on ventricular septal motion, left ventricular endocardial motion, and dimensions.
- To compare pacing-induced septal motion patterns with spontaneous left bundle branch block.
Main Methods:
- Echocardiography was used in 12 patients with normal baseline motion.
- Incremental right ventricular pacing was performed at apical, outflow, and inflow regions.
- Ventricular septal motion, endocardial motion, and dimensions were analyzed at various pacing rates.
Main Results:
- Three distinct patterns of abnormal ventricular septal motion (Types I, II, III) were observed, dependent on pacing site.
- Right ventricular apical pacing predominantly induced Type I, while outflow and inflow pacing favored Type II.
- Left ventricular dimensions decreased with pacing rate, independent of pacing site.
Conclusions:
- Ventricular septal motion abnormalities during right ventricular pacing are sequence-dependent.
- Pacing from outflow/inflow sites mimics spontaneous left bundle branch block, unlike apical pacing.
- Left ventricular dimensional changes correlate with pacing rate, not location.