Simulation Results and Analysis of Electric Field Distribution in Myocardial Tissue under Circular Electrode Electric Pulse Ablation / 中国医疗器械杂志

As a new energy source for atrial fibrillation ablation, electric pulse ablation has higher tissue selectivity and biosafety, so it has a great application prospect. At present, there is very limited research on multi-electrode simulated ablation of histological electrical pulse. In this study, a circular multi-electrode ablation model of pulmonary vein will be built on COMSOL5.5 platform for simulation research. The results show that when the voltage amplitude reaches about 900 V, it can make some positions achieve transmural ablation, and the depth of continuous ablation area formed can reach 3 mm when the voltage amplitude reaches 1 200 V. When the distance between catheter electrode and myocardial tissue is increased to 2 mm, a voltage of at least 2 000 V is required to make the depth of continuous ablation area reach 3 mm. Through the simulation of electric pulse ablation with ring electrode, the research results of this project can provide reference for the voltage selection in the clinical application of electric pulse ablation.

CT Image-based Surgery Assist System for Left Atrial Appendage Occlusion / 中国医疗器械杂志

At present, the standard left atrial appendage occlusion procedure mainly involves two-dimensional imaging methods such as X-ray fluoroscopy and transesophageal echocardiography to guide the operation, which will lead to underestimation of the three dimensional structure of the left atrial appendage and the surrounding tissue, thus adversely affects the surgery. To solve this problem, a surgery assist system for left atrial appendage occlusion based on preoperative cardiac CT images is developed. The proposed system realizes the left atrial appendage parameter measurement based on cardiac CT image, and realizes the calculation of optimal delivery sheath trajectory and three-dimensional simulation of the delivery sheath movement on the basis of a novel delivery sheath trajectory model. The system is expected to provide precise guidance for left atrial appendage occlusion, improve the success rate and safety of the operation, and at the same time help reduce the difficulty of learning the operation, and facilitate the promotion of left atrial appendage occlusion.

Assessment of quality of life and its influence factors in patients with atrial fibrillation 3 months after catheter ablation / 中国介入心脏病学杂志

Objective To investigate the quality of life and its influence factors in patients with atrial fibrillation 3 months after catheter ablation. Methods From April 2014 to February 2016,AF patients who underwent single catheter ablation in our hospital were included. The quality of life was assessed by MOS 36 item short form health survey (SF-36), and the effect of related factors on QOL scores were further analyzed. Results There were no significant changes in quality of life at baseline and 3 months after catheter ablation including physical component summary (PCS) [(70.6±17.1) vs.(72.9±10.7),P =0.078]score, mental component summary (MCS) [(70.9±12.3) vs.(71.8±12.5), P =0.44] score and SF-36 score [(70.8±13.0) vs. (72.3±10.3), P=0.138]. Multivariate analysis indicated that there was negative correlation between patients who relapsed after ablation and better quality of life(PCS, β=―3.162, P=0.036;MCS, β=―5.675, P =0.001; total SF-36 score, β=―4.385, P =0.003), MCS score and warfarin use (MCS,β=―4.020,P =0.014). There was negative correlation between PCS score and smoking(PCS, β=―3.129,P =0.037).Conclusion All patients had stable quality of life in 3 months after catheter ablation. Ablation outcome was probably the main influencing factors. The use of dabigatran and smoking might also have effects on their quality of life.

Association between CHADS2 score and long-term atrial fibrillation recurrence rate after catheter ablation / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the association between CHADS2 score and long-term ( ≥ 3 years) outcomes post catheter ablation in patients with atrial fibrillation (AF).</p><p><b>METHODS</b>AF patients who received single catheter ablation in our hospital from January 2004 to March 2009 in our department were included and patients received regular follow-up. AF recurrence was defined as the occurrence of atrial arrhythmias (AF, atrial flutter and atrial tachycardia) recorded by electrocardiogram monitor ( ≥ 30 seconds) after ablation during follow-up period (after 3 months blanking period). The relationship between baseline clinical and echocardiographic characteristics and the time to recurrence during follow-up was evaluated using Cox multivariate analysis.</p><p><b>RESULTS</b>A total of 280 patients who received single catheter ablation procedure were included in the study, 3 patients died and there were 50 patients lost to follow-up. A total of 227 patients with AF (163 paroxysmal and 64 non-paroxysmal ) were enrolled in the final analysis. During a median follow-up of 51 months (41-56 months), 109 patients experienced AF recurrences and the recurrence rate after catheter ablation ( ≥ 3 years) was 48.0% (109/227). Cox multivariate analysis showed that the high CHADS2 score (HR: 1.417, 95%CI 1.194-1.682, P < 0.001) and AF non-termination during ablation (HR: 2.077, 95%CI 1.380-3.126, P = 0.043) were risk factors of AF recurrence. AF recurrence rates in the termination and non-termination group were 41.0% (75/183) and 77.3% (34/44), respectively. In the AF termination group, the recurrence rates and the median recurrence free time in patients with CHADS2 score ≥ 3 were 80.0% (12/15) and 1 year, respectively. In the non-AF termination group, the recurrence rates in patients with CHADS2 score = 0, CHADS2 score = 1-2 and CHADS2 score ≥ 3 were 60.0% (6/10), 77.8% (21/27) and 100% (7/7), respectively; the median recurrence free time of patients with CHADS2 score = 0, CHADS2 score = 1-2 and CHADS2 score ≥ 3 were 30 months, 12 months and 6 months, respectively.</p><p><b>CONCLUSIONS</b>CHADS2 score is a predictor of AF recurrences after catheter ablation. Patients with high CHADS2 score is associated with higher risk of long-term ( ≥ 3 years) AF recurrences.</p>

Optimization of electrode location and size on simulation in electric field distribution of atrial defibrillation / 中国医疗器械杂志

A distributed simulation method of electric field based on the atrial defibrillation of the heart modeling and finite element solution is proposed in this study. In order to solve the problem that ordinary clinical trials could not measure the actual distribution of the defibrillation electric field in the heart accurately, this method provides a research tool for electrical defibrillation. A complete atrial anatomical structure in the heart model is used in the research, the finite element method is proceeded to solve; Three parameters: defibrillation threshold voltage, the high field strength rate and the defibrillation threshold energy are set to evaluate the effect of defibrillation. The heart electric field distributions of transvenous atrial defibrillation with different electrode locations or sizes are simulated. The simulation results and the reported results match fairly well, which initially verify the feasibility of this method.