Endothelial dysfunction and pathophysiological correlates in atrial fibrillation.

Area of Science:

• Cardiovascular Science
• Vascular Biology
• Integrative Physiology

Background:

• Endothelial dysfunction (ED) is characterized by impaired nitric oxide (NO)-dependent vasorelaxation, increased oxidative stress, and inflammation.
• Atrial fibrillation (AF) is recognized as a significant risk factor for developing ED.

Purpose of the Study:

• To review the evidence linking AF to ED.
• To explore the underlying mechanisms contributing to the AF-ED association.
• To discuss the pathophysiological correlates of ED in AF patients.

Main Methods:

• Review of existing literature on AF and ED.
• Analysis of proposed mechanisms including rheology, atrial function, inflammation, and systemic factors like the renin-angiotensin system (RAS).
• Examination of clinical manifestations of ED in AF.

Main Results:

• AF is associated with impaired acetylcholine-mediated blood flow, reduced plasma nitrite/nitrate, and exacerbated ED by comorbidities.
• Mechanisms include turbulent blood flow impairing NO release, reduced eNOS expression due to disorganized atrial contraction, inflammation, and RAS activation.
• Clinical correlates include muscle underperfusion and lactic acidosis during exercise.

Conclusions:

• AF significantly contributes to endothelial dysfunction through multiple interconnected pathways.
• Understanding these mechanisms is crucial for managing AF patients and mitigating cardiovascular risk.
• Targeting these pathways, such as RAS inhibition, may offer therapeutic benefits.