Introduction
Atrial fibrillation (AF) is the most common type of arrhythmia in clinic. Patients with atrial fibrillation have an increased risk of stroke, heart failure, and depression, which seriously affects the patient’s life quality[1] and increases social burden. For patients with paroxysmal atrial fibrillation (PAF), circular pulmonary vein radiofrequency ablation (CPVA) is recommended as a category I treatment[2]. Ablation therapy can improve the left atrium remodeling in AF patients[3]. Some observational studies suggest that successful AF catheter ablation and maintenance of sinus rhythm are associated with a decrease in stroke risk. However, the recurrence rate after atrial fibrillation ablation procedure is high (8%-40%)[4,5,6]. The results of ablation are affected by many factors, such as left size, serum Galectin-3, serum matrix metalloproteinase-9, etc [7-10], and the mechanism of recurrence as well as the related factors are still unclear, especially for PAF patients whose left atrium does not change significantly. Identification of the indicators that can predict recurrence after CPVA can help to develop more precise clinical strategies.
During the progression of atrial fibrillation, AF patients often have atrial remodeling, which is mainly manifested as atrial muscle degeneration, fibrosis of atrial muscle and extracellular matrix; the echocardiography often shows normal left ventricular ejection fraction (LVEF) and left ventricle inner diameter, but the atrium is enlarged[9], accompanied by varying degrees of mitral regurgitation (MR). Normal mitral valve function depends on the structural and functional integrity of the atria and ventricles. In patients with isolated left atrial (LA) enlargement, when the mitral valve annulus is not significantly expanded, the mitral valve closure can be maintained by reducing the closure area and fornix height. But after decompensation, atrial-related MR will occur. Ring et al. believed that the percentage of systolic mitral valve antagonist area to the overlapping area of front and rear leaves of the mitral valve <13%, as measured by three-dimensional transesophageal echocardiography, can be used to predict the occurrence of functional MR (A/VF-MR)[11]. In 2017, the American Society of Echocardiography and the Society of Cardiovascular Magnetic Resonance issued the latest recommendations for non-invasive assessment of the severity of MR[12], which better guides and standardizes the imaging evaluation of MR.
The clinical management of AF should be individualized. The prediction of risk factors is important for comprehensive management of atrial fibrillation. Previous studies on post-radiofrequency prediction mostly focused on methods assessing the left atrial structure and function of AF patients. There was not any predictive model based on the degree of mitral regurgitation in patients with AF. This study further combined the parameters of left atrial structure, function, and degree of MR. We constructed a joint prediction model by using real-time three-dimensional echocardiography (RT-3DE) to evaluate the volume of LA, using transesophageal echocardiograghy (TEE) to obtain the left atrial appendage function parameters, and referring to the evaluation criteria of MR recommended by the latest guidelines. We developed a prediction model for the recurrence of PAF patients after CPVA based on echocardiographic and clinical characteristics, and verify its diagnostic efficacy in the verification group. This study provided a basis for designing clinical management strategies for AF patients.
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