Nov 1, 1979

Pacing-induced alternate Wenckebach periods: incidence and clinical significance

Pacing and Clinical Electrophysiology : PACE
S LévyH Bricaud


Alternate Wenckebach periods have been defined as episodes of 2:1 atrioventricular (AV) block in which conducted P waves exhibit progressive PR prolongation until two or three successively blocked P waves. Ocurrence of this phenomenon during atrial pacing has been established. Thirty-six patients were studied and right atrial pacing was achieved at increasing rates up to 350 beats/min in order to induce alternate Wenckebach periods. His bundle recordings were obtained in every patient. The patients were subdivided into three groups according to the AV nodal conduction time (AH interval): normal AH (75-130 ms) was present in 17 patients, short AH (70 ms) in 13 patients and prolonged AH (130 ms) in eight patients. Alternate Wenckebach periods were observed in 29 patients (80.5%). In every patient alternate Wenckebach periods occurred at the AV node level. Atrial pacing failed to induce alternate Wenckebach periods in seven patients, six of whom belonged to the short AH group. In four patients 3:1 block never appeared because of block at the atrial level. Two patients presented 2:1 and 3:1 infrahissian block without significant AH prolongation. The remaining patient developed atrial fibrillation. Alternate Wenckebach periods were ...Continue Reading

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Mentioned in this Paper

Heart Block
Intravenous Injections
Left Bundle Branch of His
Right Atrial Structure
Atrial Fibrillation
Cardiac Conduction System
Structure of Atrioventricular Node
Cardiac Pacing, Artificial
Electrocardiographic Recorders

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