What question did this study set out to answer?

To determine whether intrinsic cardiac nerves modulating electrical conduction develop denervation supersensitivity to acetylcholine and nicotine after surgical cardiac denervation.

July 1, 1983AJP Heart and Circulatory Physiology

Altered nicotinic sensitivity of AV node in surgically denervated canine hearts

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Why the study?

Does intracoronary acetylcholine and nicotine alter conduction times differently in normal versus cardiac-denervated canine hearts?

Key Points

To determine whether intrinsic cardiac nerves modulating electrical conduction develop denervation supersensitivity to acetylcholine and nicotine after surgical cardiac denervation.
Evaluated control dogs (n = 18) and surgically denervated dogs (n = 18) placed on cardiopulmonary bypass.
Measured intra-atrial (P-A), intraventricular (H-V), and atrioventricular nodal (A-H) conduction times from the His bundle region following intracoronary delivery of acetylcholine (0.1–10 µg) and nicotine (0.1–400 µg).
Denervated dogs exhibited approximately a 10-fold increase in the negative dromotropic effect of nicotine on atrioventricular nodal conduction compared to control animals.
Intra-atrial (P-A) and intraventricular (H-V) conduction intervals showed no evidence of supersensitivity to either acetylcholine or nicotine in the denervated group.
Muscarinic sensitivity of the atrioventricular node to direct acetylcholine administration remained unchanged following surgical denervation.

Structured PICO

Does intracoronary acetylcholine and nicotine alter conduction times differently in normal versus cardiac-denervated canine hearts?

Population

36 dogs (18 control, 18 cardiac-denervated) placed on cardiopulmonary bypass

Intervention

Intracoronary administration of acetylcholine (0.1-10 micrograms) and nicotine (0.1-400 micrograms)

Comparator

Control dogs (n=18) compared to cardiac-denervated dogs (n=18)

Outcome

Intra-atrial (P-A), intraventricular (H-V), and atrioventricular (AV) nodal (A-H) conduction times recorded from the region of the His bundlesurrogate

Intrinsic cardiac nerves display denervation supersensitivity, as evidenced by a 10-fold increase in the negative dromotropic effect of nicotine on AV nodal conduction time in surgically denervated canine hearts.

Discussion

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Implication

Denervation supersensitivity to nicotine at the AV node should not alter practice; hypothesis-generating for autonomic responses in human cardiac denervation.

Cite This Study

Priola et al. (1983) studied this question.

synapsesocial.com/papers/6a90f1d4828b782fecc1a108 https://doi.org/10.1152/ajpheart.1983.245.1.h27

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Implication

Denervation supersensitivity to nicotine at the AV node should not alter practice; hypothesis-generating for autonomic responses in human cardiac denervation.

Altered nicotinic sensitivity of AV node in surgically denervated canine hearts

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Altered nicotinic sensitivity of AV node in surgically denervated canine hearts

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Also Consider

Also Consider