The Atrial Electro-mechanical Function After Successful Cardioversion In Paroxsmal Atrial Fibrillation By Radiofrequency Ablation

Atrium which is an indispensable part of the heart plays three important functions including channel, storage and booster pump. At present, the hemodynamic of atrial is evaluated only by echocardiography, which can not fully evaluate the atrial electro-mechanical function. Resently, few researches have combined the three-dimensional ECG, echocardiography and tissue Doppler strain imaging technologies to assess the atrial function. In addition, with the increase of patients suffering from atrial fibrillation, radiofrequency catheter ablation has become a first-line treatment. The comprehensive assessment of atrial function is needed. In this study, atrial electrical, mechanical, hemodynamic function of different age groups of healthy individuals were evaluated comprehensively by three-dimensional ECG and echocardiography.Then, better indicators for atrial evaluation were further applied to assess function of atrium before and after the AF ablation.The subjects were divided into two groups, Group I: thirty healthy young volunteers and middle-aged people who come to our hospital for physical examination. Group II:(1) 20 patients with paroxysmal atrial fibrillation, aged 40-70 years.(2) Control group: 20 healthy individuals whose age, gender and blood pressure are matched with paroxysmal atrial fibrillation group. Simultaneous record of all three-dimensional and conventional 12-lead ECG, echocardiography of two groups were compared. In the first group, every participant was examined carefully by stereoscopic 3D-ECG, color Doppler echocardiography. In the second group, stereoscopic 3D-ECG, color Doppler echocardiography, three-dimensional electro-anatomical mapping system, programmed stimulator, digital subtraction X-ray machine, multi-channel electrophysiology recorder and related radiofrequency ablation catheters and other equipment were used to examine all the patients and the people in control group. For AF patients, follow-up examinations were done at1, 3 and 6 months after ablation.Data were statistically analyzed using SPSS 19.0. All data were reported as mean ± SD. Two groups were compared with t-test for independent samples. The relationship pearson linear correlation analysis between each measured values. P <0.05 was regarded as statistically significant between groups.The results of this set of experiments are as follows:The results of the first group of volunteers showed that P-wave vector rings and atrial volume parameters were within normal range. Mechanical movement of atrium wall by strain rate imaging analysis found that movement sync occurred between the atrium left, right and atrial wall interval. Conduction time and amplitude of atrial with atrial volume were positively correlated. Strain and atrial volume were correlated. P atrial amplitude and mechanical movement had no significant correlation. Atrium systolic strain A, speed A and the left and right atrial total volume, systolic emptying had no correlation. Electrical activity and the mechanical motion parameters between the two groups were significantly different. Hemodynamic function parameters did not change significantly. With age increasing, atrial electrical activity and mechanical movement of healthy people changed, which suggested that atrial wall matrix change with increasing age. to provide a basis for atrial arrhythmias. Hemodynamic function did not significantly change, indicating hemodynamic function can keep well-functioned in the absence of other factors.Group II: There were no significant differences between the groups at baseline parameters. Compared with the control group, P-wave duration prolongation, amplitude increase, atrial enlargement accompanied by reduction of atrial contractility, strain rate A decrease were found in AF patients. At the same time, atrial compliance indicators reduced as follows: rain rate E reduce, indicating atrial compliance, storage and pipeline function significantly changed.Atrial parameters after one month: Compared to baseline of atrial electrocardiogram, echocardiography parameters, conduction, mechanical movement and shape of atrial fibrillation began to improve. Atrial parameters after 3 months: Conduction, mechanical movement and morphology of atrial fibrillation were significantly improved, P-wave duration improved, amplitude decreased, left atrial, right atrial diameter and volume were significantly improved. Atrial pump function and compliance improved, Strain rate A was decresed, S-wave was significantly increased, E wave was decresed. Atrial parameters after 6 months: In ablation group, P-wave duration and amplitude had more obvious improvement, and left atrium, right atrial diameter and volume further improved. Atrial pump function and compliance further improved, with strain rate A was further decresed, S-wave was more significantly increased, E wave was further decresed. This indicated that the morphology of atrial reconstructed, most contraction parameters as compared to the control group improved. Mechanical parameters can be used as sensitive indicators to evaluate early recovery of atrial function.Consequently, the indicators did not satisfactorily improved compared with the control group, reflecting the atrial structure had persistent, irreversible changes in the patients with atrial fibrillation.The results show that:1. With age increasing, the atrial electrical activity, mechanical movement of healthy population changed, while no significant changes were found in hemodynamic function.2. Three-dimensional ECG and doppler echocardiography can evaluate the electrical conductivity, mechanical motion and hemodynamic function of atrium simultaneously, the three closely related means could evaluate the cardiac function comprehensively.3. The study found that the combined application of ECG with strain rate imaging is a simple method to evaluate atrial electrical activity and atrial mechanical function changes in patients with atrial fibrillation ablation. Improvement of electrical and structural remodeling can be observed after ablation of atrial fibrillation.4. Mechanical parameters can be used as sensitive indicators to evaluate early recovery of atrial function.