[Effects of the autonomic nervous system on the refractory periods of atrioventricular conduction in man].
The purpose of the work is to evaluate in clinical setting the effects of autonomic nervous system on the refractory periods of atrio-ventricular (A-V) conduction. Electrophysiological study was carried out, both during basal state and after autonomic blockade induced by i.v. administration of propranolol 0.2 mg/Kg and atropine 0.04 mg/Kg, in 21 subjects with normal atrio-ventricular node conduction (A-H less than or equal to 120 msec) and normal sinus rate (mean age: 54.3 +/- 16.3 years). Following autonomic blockade the sinus cycle length decreased significantly (P less than 0.01), whereas A-H interval, A1-H1 interval at cycle length of 460 msec and the longest atrial pacing cycle length inducing Wenckebach block did not change significantly. Effective and functional refractory periods of the A-V node did not show significant variations after autonomic blockade (342.2 +/- 41 versus 337.2 +/- 54.2 msec and 435.9 +/- 58.9 versus 430 +/- 60.9 msec, respectively); however, these refractory periods changed variably from subject to subject; in some patients they increased and in others there was a marked decrease. There were no significant variations of atrial effective and functional refractory periods after autonomic blockade (249.5 +/- 29.6 versus 256.6 +/- 31.9 msec and 276.4 +/- 27.1 versus 287.7 +/- 33.4 msec, respectively); they too showed a variable response from subject to subject. The relative refractory period of His-Purkinje system, evaluated in 3 patients, increased in all after autonomic blockade (420 +/- 20 versus 463.3 +/- 15.2 msec).(ABSTRACT TRUNCATED AT 250 WORDS)
D000293:Adolescent; D000328:Adult; D000368:Aged; D001283:Atrioventricular Node / Q000187:drug effects / Q000502:physiology; D001285:Atropine / Q000494:pharmacology; D001341:Autonomic Nervous System / Q000502:physiology*; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011433:Propranolol / Q000494:pharmacology
D001285:Atropine; D011433:Propranolol
Effetti del sistema neurovegetativo sui periodi refrattari della conduzione atrio-ventricolare nell'uomo.