Alterations in subsidiary pacemaker function after prolonged subsidiary pacemaker dominance in the canine right atrium

George J Rozanski, Stephen L. Lipsius, Walter C. Randall, Stephen B. Jones

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

In vivo and in vitro techniques were used to study the functional characteristics of subsidiary atrial pacemaker activity 4 to 11 months after surgical excision of the sinoatrial node region of the dog heart. Characteristics of this long-term subsidiary atrial pacemaker activity were compared with those of sinoatrial node and shortterm subsidiary atrial pacemaker activities. Extracellular bipolar electrodes were used to estimate the site of earliest activation and monitor spontaneous rate. Under both in vivo and in vitro conditions, long-term pacemaker activity was located in the same region of the inferior right atrium as was short-term pacemaker activity. Under in vitro conditions, long-term activity was characterized by a reduced sensitivity to acetylcholine and overdrive pacing and by a lack of dependence on beta-adrenergic stimulation compared with short-term activity. Furthermore, long-term pacemaker activity was more sensitive to acetylcholine and less sensitive to norepinephrine (>10−7M) compared with sinoatrial node activity. It is concluded that the subsidiary atrial pacemakers that emerge soon after removal of the sinoatrial node are the same as those pacemakers that ultimately assume long-term control of the heart. In addition, after subsidiary atrial pacemakers assume dominant pacemaker function, their dependence on norepinephrine and their response to acetylcholine and overdrive pacing are reduced. These changes facilitate a more stable regulation of atrial pacemaker rhythm and, thereby, make subsidiary atrial pacemaker function more like that of the sinoatrial node.

Original languageEnglish (US)
Pages (from-to)535-542
Number of pages8
JournalJournal of the American College of Cardiology
Volume4
Issue number3
DOIs
StatePublished - Jan 1 1984

Fingerprint

Sinoatrial Node
Heart Atria
Canidae
Acetylcholine
Norepinephrine
Atrial Function
Adrenergic Agents
Electrodes
Dogs
In Vitro Techniques

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Cite this

Alterations in subsidiary pacemaker function after prolonged subsidiary pacemaker dominance in the canine right atrium. / Rozanski, George J; Lipsius, Stephen L.; Randall, Walter C.; Jones, Stephen B.

In: Journal of the American College of Cardiology, Vol. 4, No. 3, 01.01.1984, p. 535-542.

Research output: Contribution to journalArticle

Rozanski, George J ; Lipsius, Stephen L. ; Randall, Walter C. ; Jones, Stephen B. / Alterations in subsidiary pacemaker function after prolonged subsidiary pacemaker dominance in the canine right atrium. In: Journal of the American College of Cardiology. 1984 ; Vol. 4, No. 3. pp. 535-542.
@article{de11fe9838b948ada51217e95233cca2,
title = "Alterations in subsidiary pacemaker function after prolonged subsidiary pacemaker dominance in the canine right atrium",
abstract = "In vivo and in vitro techniques were used to study the functional characteristics of subsidiary atrial pacemaker activity 4 to 11 months after surgical excision of the sinoatrial node region of the dog heart. Characteristics of this long-term subsidiary atrial pacemaker activity were compared with those of sinoatrial node and shortterm subsidiary atrial pacemaker activities. Extracellular bipolar electrodes were used to estimate the site of earliest activation and monitor spontaneous rate. Under both in vivo and in vitro conditions, long-term pacemaker activity was located in the same region of the inferior right atrium as was short-term pacemaker activity. Under in vitro conditions, long-term activity was characterized by a reduced sensitivity to acetylcholine and overdrive pacing and by a lack of dependence on beta-adrenergic stimulation compared with short-term activity. Furthermore, long-term pacemaker activity was more sensitive to acetylcholine and less sensitive to norepinephrine (>10−7M) compared with sinoatrial node activity. It is concluded that the subsidiary atrial pacemakers that emerge soon after removal of the sinoatrial node are the same as those pacemakers that ultimately assume long-term control of the heart. In addition, after subsidiary atrial pacemakers assume dominant pacemaker function, their dependence on norepinephrine and their response to acetylcholine and overdrive pacing are reduced. These changes facilitate a more stable regulation of atrial pacemaker rhythm and, thereby, make subsidiary atrial pacemaker function more like that of the sinoatrial node.",
author = "Rozanski, {George J} and Lipsius, {Stephen L.} and Randall, {Walter C.} and Jones, {Stephen B.}",
year = "1984",
month = "1",
day = "1",
doi = "10.1016/S0735-1097(84)80098-4",
language = "English (US)",
volume = "4",
pages = "535--542",
journal = "Journal of the American College of Cardiology",
issn = "0735-1097",
publisher = "Elsevier USA",
number = "3",

}

TY - JOUR

T1 - Alterations in subsidiary pacemaker function after prolonged subsidiary pacemaker dominance in the canine right atrium

AU - Rozanski, George J

AU - Lipsius, Stephen L.

AU - Randall, Walter C.

AU - Jones, Stephen B.

PY - 1984/1/1

Y1 - 1984/1/1

N2 - In vivo and in vitro techniques were used to study the functional characteristics of subsidiary atrial pacemaker activity 4 to 11 months after surgical excision of the sinoatrial node region of the dog heart. Characteristics of this long-term subsidiary atrial pacemaker activity were compared with those of sinoatrial node and shortterm subsidiary atrial pacemaker activities. Extracellular bipolar electrodes were used to estimate the site of earliest activation and monitor spontaneous rate. Under both in vivo and in vitro conditions, long-term pacemaker activity was located in the same region of the inferior right atrium as was short-term pacemaker activity. Under in vitro conditions, long-term activity was characterized by a reduced sensitivity to acetylcholine and overdrive pacing and by a lack of dependence on beta-adrenergic stimulation compared with short-term activity. Furthermore, long-term pacemaker activity was more sensitive to acetylcholine and less sensitive to norepinephrine (>10−7M) compared with sinoatrial node activity. It is concluded that the subsidiary atrial pacemakers that emerge soon after removal of the sinoatrial node are the same as those pacemakers that ultimately assume long-term control of the heart. In addition, after subsidiary atrial pacemakers assume dominant pacemaker function, their dependence on norepinephrine and their response to acetylcholine and overdrive pacing are reduced. These changes facilitate a more stable regulation of atrial pacemaker rhythm and, thereby, make subsidiary atrial pacemaker function more like that of the sinoatrial node.

AB - In vivo and in vitro techniques were used to study the functional characteristics of subsidiary atrial pacemaker activity 4 to 11 months after surgical excision of the sinoatrial node region of the dog heart. Characteristics of this long-term subsidiary atrial pacemaker activity were compared with those of sinoatrial node and shortterm subsidiary atrial pacemaker activities. Extracellular bipolar electrodes were used to estimate the site of earliest activation and monitor spontaneous rate. Under both in vivo and in vitro conditions, long-term pacemaker activity was located in the same region of the inferior right atrium as was short-term pacemaker activity. Under in vitro conditions, long-term activity was characterized by a reduced sensitivity to acetylcholine and overdrive pacing and by a lack of dependence on beta-adrenergic stimulation compared with short-term activity. Furthermore, long-term pacemaker activity was more sensitive to acetylcholine and less sensitive to norepinephrine (>10−7M) compared with sinoatrial node activity. It is concluded that the subsidiary atrial pacemakers that emerge soon after removal of the sinoatrial node are the same as those pacemakers that ultimately assume long-term control of the heart. In addition, after subsidiary atrial pacemakers assume dominant pacemaker function, their dependence on norepinephrine and their response to acetylcholine and overdrive pacing are reduced. These changes facilitate a more stable regulation of atrial pacemaker rhythm and, thereby, make subsidiary atrial pacemaker function more like that of the sinoatrial node.

UR - http://www.scopus.com/inward/record.url?scp=0021229472&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0021229472&partnerID=8YFLogxK

U2 - 10.1016/S0735-1097(84)80098-4

DO - 10.1016/S0735-1097(84)80098-4

M3 - Article

VL - 4

SP - 535

EP - 542

JO - Journal of the American College of Cardiology

JF - Journal of the American College of Cardiology

SN - 0735-1097

IS - 3

ER -