Baroreceptor control of atrioventricular conduction in man

G. Mancia, O. Bonazzi, L. Pozzoni, A. Ferrari, M. Gardumi, L. Gregorini, R. Perondi

Research output: Contribution to journalArticlepeer-review

Abstract

Although human baroreflexes are known to exert a powerful physiological control on heart rate, little information exists on the physiological control they exert on the atrioventricular conduction system. In 11 normotensive subjects with normal atrioventricular conduction, the authors altered baroreceptor activity by injection of pressor and depressor drugs (phenylephrine and trinitroglycerin) and recorded mean pressure (MAP, catheter measurements), R-R interval, and pre-His and post-His intervals (A-H and H-V, His bundle recording). With the subjects in sinus rhythm, increasing MAP by 21 ± 1 mm Hg caused a marked lengthening (250 ± 28 msec), and decreasing MAP by 17 ± 2 mm Hg a marked shortening (142 ± 16 msec) of the R-R interval. There was little change in the A-H interval and no change at all in the H-V interval. However, when the R-R interval kept constant in these subjects by atrial pacing, a similar increase and decrease in MAP caused, respectively, a marked lengthening (49 ± 6 msec) and shortening (19 ± 3 msec) of the A-H interval, although the H-V interval remained unaffected. Thus physiological ranges of baroreceptor activation have a marked influence on the atrioventricular node but apparently not on the ventricular portion of the atrioventricular conduction system. This influence is unmasked when pacing prevents the baroreceptor influence on the sinoatrial node.

Original languageEnglish
Pages (from-to)752-758
Number of pages7
JournalCirculation Research
Volume44
Issue number6
Publication statusPublished - 1979

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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