Mar 1, 1994

Overdrive prolongation of refractoriness and fatigue in the early stages of human bundle branch disease

Journal of the American College of Cardiology
P A ChialeM B Rosenbaum

Abstract

The aim of this study was to assess the response of refractoriness in normal and diseased human bundle branches to changes in cycle length, as well as during a long period of continuous overdrive pacing. The anterograde refractory period of the bundle branches in patients with functional bundle branch block shortens as the rate is increased. The rate-dependent response of refractoriness in diseased bundle branches is quite different. However, this difference has not been precisely delineated, and its physiologic meaning is uncertain. Refractoriness of the bundle branches was measured by the extrastimulus technique in 16 patients with tachycardia-dependent bundle branch block and 10 patients with functional bundle branch block, both after basic trains of 8 atrial-paced impulses at different cycle lengths and during a 10-min period of continuous overdrive pacing. The baseline refractory period in the bundle branches of patients with functional bundle branch block measured 430 +/- 32 ms (mean +/- SD) and shortened to 368 +/- 30 ms at the shortest cycle length. The maximal effect was reached within the 1st min of overdrive pacing. The baseline refractory period of the bundle branches was significantly longer in patients with tachyc...Continue Reading

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Citations

Mentioned in this Paper

Paroxysmal Reciprocal Tachycardia
Supraventricular Tachycardia
Sodium Channel Blockers
Left Bundle Branch of His
Ajmaline
Bundle-Branch Block
Sodium Channel Antagonists [MoA]
Refractory Period
Tachmalin
Cardiac Conduction System

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