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Procainamide and retrograde atrioventricular nodal conduction in man
Circulation
|February 1, 1982
Summary
Intravenous procainamide (PA) depresses retrograde atrioventricular (AV) nodal conduction in most patients. This effect does not indicate the presence of AV nodal bypass tracts, contrary to previous suggestions.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Previous studies suggested procainamide (PA) might help identify atrioventricular (AV) nodal bypass tracts by its effect on retrograde conduction.
- The precise electrophysiologic effects of PA on normal AV nodal conduction needed further clarification.
Purpose of the Study:
- To investigate the electrophysiologic effects of intravenous procainamide (PA) on retrograde atrioventricular (AV) nodal conduction in patients without known reentrant tachycardia or accessory pathways.
Main Methods:
- Electrophysiologic study in 13 patients without AV nodal reentrant tachycardia or accessory pathways.
- Intravenous administration of procainamide (10 mg/kg).
- Recording of ventriculoatrial (VA) conduction using intracardiac electrograms, incremental ventricular pacing, and ventricular extrastimulation before and after PA administration.
Main Results:
- Procainamide (PA) abolished retrograde AV nodal conduction in 5/13 patients and prolonged the cycle length for VA block in 7/13 patients.
- PA invariably prolonged the VA interval at comparable pacing cycle lengths.
- PA abolished or prolonged retrograde H2A2 intervals during ventricular premature stimulation in most patients.
Conclusions:
- Intravenous procainamide (PA) uniformly depresses retrograde AV nodal conduction in the intact human heart.
- The observed depressant effect of PA on retrograde AV nodal conduction is not indicative of the presence of AV nodal bypass tracts.
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