Ultrasonography Evaluation Of Vascular Endothelial Function In Patients With Lone Atrial Fibrillation

Background Atrial fibrillation (AF) is one of the most common arrhythmia which is common in patients with organic heart disease or other organic diseases. A few AF of unknown is called lone AF. Thromboembolic complications which (especially cerebral embolism) caused by AF is one of the most important reason for which AF patients died or were disabled. Recent years, with the physiological and pathological studying of in-depth on AF, we found that AF impairs endothelial function, which play an important role in the development and prognosis of AF. At present, the clinical studies of vascular endothelial function in patients with AF tend to take blood samples to measure markers of endothelial injury, such as nitric oxide(NO), endothelin and von Willebrand molecules, thrombomodulin, E-selectin, etc, but it is not used as a regular application. It is a non-invasive approach to evaluate the systemic endothelium-dependent dilation(EDD) through the brachial artery flow-mediated dilation (FMD) responses with ultrasound. There are reports on application of ultrasound in assessment of EDD in patients with AF abroad. Domestic studies on application of ultrasound in assessment of EDD almost aim at the patients with risk factors of coronary atherosclerosis, such as hypertension, coronary heart disease, diabetes mellitus, Kawasaki disease, hyperlipidemia, smoking and so on. Studying on the endothelial function in patients with lone AF is rarely seen.Objective To explore the clinical value of ultrasound in assessment of the endothelial function in patients with lone AF.Methods Thirty-two patients with lone AF and twenty-five healthy subjects which matched in age and gender were enrolled. The diameter of the brachial artery was measured with ultrasound in quiet state, after reactive hyperemia test and after sublingual nitroglycerin administration, the percentage change was calculated. Left ventricular end-diastolic diameter (LVDd), the rate of left ventricular fractional shortening (FS), ejection fraction (EF) was calculated and recorded with routine echocardiography. Left atrial volume was measured with the modified Simpson double-plane method.Results FMD of brachial artery in patients with lone AF were significantly lower than that in the healthy subjects([6.14±2.03]% vs [16.50±5.00]%, P<0.01); NTG-MD of brachial artery in patients with lone AF had no significant difference with that in the healthy subjects(P>0.05). Left atrium volume of the patients with lone AF were significantly higher than that of the healthy subjects([45.85±13.72] ml vs [27.33±6.51] ml, P<0.01). FMD of brachial artery showed significant correlation to left atrium volume in patients with lone AF (r=-0.62, P<0.01).Conclusion EDD is impaired in patients with lone AF. The Doppler ultrasound technique is an effective way to assess endothelial function in patients with lone AF. The left atrial volume increase significantly in patients with lone AF. There is correlation between FMD of brachial artery and left atrium volume in all patients with lone AF.