Document Detail

Modification of the baroreceptor control of atrio-ventricular conduction induced by digitalis in man.
MedLine Citation:
PMID:  6414704     Owner:  NLM     Status:  MEDLINE    
Several studies in animals and in man have suggested that the inhibitory influence of baroreceptors on heart rate and peripheral circulation is enhanced by digitalis. Because the atrio-ventricular node represents a key site for the clinical action of digitalis we studied how baroreceptor control of atrio-ventricular conduction is modified by digitalis at therapeutical doses. In eight subjects heart rate was kept constant by atrial pacing to assess neural influences on atrio-ventricular conduction rate without the modifications caused by simultaneous changes in cardiac cycle length. Arterial baroreceptors were stimulated by increasing or reducing blood pressure (intra-arterial recording), via an iv bolus of phenylephrine or nitroglycerine. The baroreflex sensitivity was assessed in ms . mmHg-1 as the slope of the linear regressions relating the rise or fall in systolic blood pressure to the lengthening or shortening in St- (atrial stimulus artifact) Q interval (ECG recording). The study was performed before and 45 min after iv administration of digitalis (0.8 mg of Lanatoside C). Baroreflex sensitivity during baroreceptor stimulation was 2.9 +/- 1.1 ms . mmHg-1 (mean +/- SE) before digitalis, whereas after digitalis a significantly and markedly greater value of 5.6 +/- 1.5 ms . mmHg-1 was found. Baroreflex sensitivity during baroreceptor deactivation was 0.9 +/- 0.1 ms . mmHg-1 before digitalis, and was not significantly affected by the drug. Thus in man the baroreceptor control of atrio-ventricular conduction is strikingly potentiated by digitalis although this potentiation is only evident in the upper portion of the stimulus-response curve of the reflex.(ABSTRACT TRUNCATED AT 250 WORDS)
A Ferrari; O Bonazzi; L Gregorini; M Gardumi; R Perondi; G Mancia
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Cardiovascular research     Volume:  17     ISSN:  0008-6363     ISO Abbreviation:  Cardiovasc. Res.     Publication Date:  1983 Oct 
Date Detail:
Created Date:  1983-12-17     Completed Date:  1983-12-17     Revised Date:  2009-10-29    
Medline Journal Info:
Nlm Unique ID:  0077427     Medline TA:  Cardiovasc Res     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  633-41     Citation Subset:  IM    
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MeSH Terms
Atrioventricular Node / physiology*
Blood Pressure / drug effects
Heart Conduction System / physiology*
Hypertension / physiopathology
Lanatosides / pharmacology*
Nitroglycerin / pharmacology
Phenylephrine / pharmacology
Pressoreceptors / drug effects*,  physiology
Reflex / drug effects
Sinoatrial Node / physiology
Reg. No./Substance:
0/Lanatosides; 17575-22-3/lanatoside C; 55-63-0/Nitroglycerin; 59-42-7/Phenylephrine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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