Abstract
Effects of the autonomic nervous system on inducibility of A-V nodal reentrant tachycardia (AVNR) were studied in 5 patients. In 4 of 5 patients, AVNR which used slow pathway (SPW) for antegrade and fast pathway (FPW) for retrograde conduction was induced following a sudden jump in A-H interval (100-200 cosec) by programmed right atrial stimulation during control state. Intravenous propranolol (4mg) prevented induction of AVNR by selectively suppressing antegrade SPW conduction in 2 of these 4 patients, whereas intravenous atropine (1mg) or intravenous infusion of isoproterenol (1μg/min) prevented induction of AVNR by selectively augmenting antegrade FPW conduction in another 2 patients. One patient developed a sudden jump and inducible AVNR only after atropine administration.
These results suggest that change in autonomic tone does not always affect selectively the antegrade conduction via SPW, and sympathetic stimulation does not always facilitate induction of AVNR in patients with dual A-V nodal pathways.
