What question did this study set out to answer?

To determine whether reduced left atrial nitric oxide levels during atrial fibrillation are associated with an increase in local superoxide production.

August 30, 2005Circulation

Atrial Fibrillation Increases Production of Superoxide by the Left Atrium and Left Atrial Appendage

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Authors

SDSamuel C. DudleyElectrophysiology NHNyssa E. HochEmory University LMLouise McCannVanderbilt University

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Implication

Increased LAA superoxide may promote thrombogenicity in AF; leaves open whether antioxidants alter clinical outcomes.

Key Points

To determine whether reduced left atrial nitric oxide levels during atrial fibrillation are associated with an increase in local superoxide production.
Induced atrial fibrillation in pigs for one week using rapid atrial pacing, comparing them to control pigs maintained at equivalent ventricular heart rates.
Measured superoxide production in acutely isolated left atrium and left atrial appendage tissue using electron spin resonance and superoxide dismutase-inhibitable cytochrome C reduction assays.
Assessed enzymatic sources and regulators of superoxide by quantifying NAD(P)H oxidase activity, xanthine oxidase activity, and GTP-loaded Rac1 levels in tissue homogenates.
Basal superoxide production increased 2.7-fold (P<0.01) in the left atrium and 3.0-fold (P<0.02) in the left atrial appendage by electron spin resonance, alongside a 3.0-fold increase in the appendage via cytochrome C assay (P<0.01).
Total superoxide dismutase activity remained unchanged, while pharmacological inhibition with apocynin or oxypurinol significantly reduced appendage superoxide levels.
Left atrial appendage tissue demonstrated significant increases in NAD(P)H oxidase activity (P=0.04), xanthine oxidase activity (P=0.01), and elevated GTP-loaded Rac1 without changes in NADPH oxidase subunit expression.

Cite This Study

Dudley et al. (2005) studied this question.

synapsesocial.com/papers/69f178c17439b1e222bf4973 https://doi.org/10.1161/circulationaha.105.538108

Topics

Atrial fibrillation Persistent AF management Anticoagulation in AF

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Atrial Fibrillation Increases Production of Superoxide by the Left Atrium and Left Atrial Appendage

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Key Points

Cite This Study

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Atrial Fibrillation Increases Production of Superoxide by the Left Atrium and Left Atrial Appendage

Discussion

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Implication

Key Points

Cite This Study

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