Ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation

Objective: to evaluate the efficacy and safety of ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation. Methods: The study population consisted of 9 patients with 5 males and 4 females enrolled consecutively who had idiopathic paroxysmal atrial fibrillation(AF). The ultrasound balloon was positioned through a special sheath to the orifice of the target vein by a transseptal procedure. The balloon was inflated with contrast-mixed saline (contrast: saline = 1:4) whose volume was decided by the diameter of the target pulmonary vein. The ablation energy was usually set up at 35 to 40 watts with temperature controlled at 60℃. The duration of each ablation was about 120 seconds which was repeated not over 10 times. Results: The average duration of the total procedure was 132±68 min for our patients. The average fluoroscopy time was 33±17 min. With a mean follow-up of 16±8 months after the procedure, AF was completely eliminated in 4 patients without antiarrhythmic drugs. The episodes of atrial fibrillation were eliminated in 2 patients with low dosage of oral amiodarone (0.1, once daily) which was ineffective before the procedure. The frequency of episodes was similar to that before the procedure in 3 patients. There were no complications such as hemopericardium, air embolism and stenosis of the pulmonary veins by angiography, related to the procedure. Conclusion: Ultrasound ablation of the pulmonary veins is a new approach to treat paroxysmal atrial fibrillation. Before we determined its value, we need to do more researches with bigger sample, randomization and comparison design.     

Segmental radiofrequency ablation of pulmonary vein ostia for patients with refractory paroxysmal atrial fibrillation using multi-slice spiral computed tomography guidance

INTRODUCTION Pulmonary veins(PV)may play an importantrole in both the initiation and maintenance of parox-ysmal atrial fibrillation(AF)(Fynn and Kalman,2004).Curative treatment of patients with paroxys-mal AF is possible by radiofrequency ablation,mak-ing segmental or linear lesions around the ostia ofPVs using a3-dimentional mapping system(Carto)(Pappone et al.,2000;2001;Oral et al.,2003).Multi-slice spiral computed tomography(MSCT)could generate a3-dimentional image of left atrium…     

Non-pulmonary vein foci induced before and after pulmonary vein isolation in patients undergoing ablation therapy for paroxysmal atrial fibrillation: incidence and clinical outcome

Objective

To evaluate the incidence and clinical outcome of adenosine triphosphate (ATP) plus isoproterenol (ISP)-induced non-pulmonary vein (PV) foci before and after circumferential PV isolation (CPVI) during index ablation in patients with paroxysmal atrial fibrillation (PAF).

Methods

In 80 consecutive patients undergoing catheter ablation for drug-refractory, symptomatic PAF at our hospital from April 2010 to January 2011, atrial fibrillation (AF) was provoked with ATP (20 mg) and ISP (20 μg/min) administration before and after CPVI. The spontaneous initiation of AF was mapped and recorded.

Results

Before ablation, AF mostly originating from PVs (PV vs. non-PV, 36/70 vs. 3/70; P<0.01) was induced in 39 patients with sinus rhythm. CPVI significantly suppressed AF inducibility; however, more non-PV foci were provoked (post-CPVI vs. pre-CPVI, 13/76 vs. 3/70; P=0.016). Patients with pre- and post-CPVI induced AF (n=49) were divided according to non-PV foci being induced (group N, n=17) or not (group P, n=32). After mean (19.2±8.2) months follow-up, 88.2% (15/17) and 65.6% (21/32) of patients in groups N and P, respectively, were free from AF recurrence (P=0.088).

Conclusions

ATP+ISP administration effectively provokes non-PV foci, especially after CPVI in PAF patients. Although in this study difference did not achieve statistical significance, supplementary ablation targeting non-PV foci might benefit clinical outcome.     

Clinical considerations of anticoagulation therapy for patients with atrial fibrillation

Atrial fibrillation (AF) increases the risk of stroke. New anticoagulation agents have recently provided alternative and promising approaches. This paper reviews the current state of anticoagulation therapy in AF patients, focusing on various clinical scenarios and on comparisons, where possible, between western and eastern populations.     

Current progress of computational modeling for guiding clinical atrial fibrillation ablation

Journal of Zhejiang University-SCIENCE B - Atrial fibrillation (AF) is one of the most common arrhythmias, associated with high morbidity, mortality, and healthcare costs, and it places a...     

High accuracy in automatic detection of atrial fibrillation for Holter monitoring

Atrial fibrillation (AF) has been considered as a growing epidemiological problem in the world, with a substantial impact on morbidity and mortality. Ambulatory electrocardiography (e.g., Holter) monitoring is commonly used for AF diagnosis and therapy and the automated detection of AF is of great significance due to the vast amount of information provided. This study presents a combined method to achieve high accuracy in AF detection. Firstly, we detected the suspected transitions between AF and sinus rhythm using the delta RR interval distribution difference curve, which were then classified by a combination analysis of P wave and RR interval. The MIT-BIH AF database was used for algorithm validation and a high sensitivity and a high specificity (98.2% and 97.5%, respectively) were achieved. Further, we developed a dataset of 24-h paroxysmal AF Holter recordings (n=45) to evaluate the performance in clinical practice, which yielded satisfactory accuracy (sensitivity=96.3%, specificity=96.8%).     

血脂对老年慢性心房颤动患者缺血性中风的影响

目的探讨血脂对老年慢性心房颤动(chronic atrial fibrillation,CAF)患者发生缺血性中风的影响.方法对资料完整的182例老年(＞60岁)CAF患者进行前瞻性研究,分析血脂与缺血性中风的关系.结果老年CAF患者血清胆固醇和甘油三酯增高、高密度脂蛋白降低与缺血性中风有明显关系(P＜0.05),其中胆固醇增高与缺血性中风关系最显著(P＜0.001).结论血脂异常是老年CAF患者发生缺血性中风的重要危险因素.     

Investigation of a spherical-section ultrasound phased array for hepatic ablation

A 3D ultrasound thermal model with a 3D finite element representation for modeling the thermal diffusion effects for hepatic ablation induced by spherical-section ultrasound phased array was developed. The model was first validated against available published measured data in rat liver. Using the validated model,effects of blood perfusion and heating schemes on lesion formation were studied for both single focus and split-focus intensity patterns. It was shown that for single focus sonication pattern the short-duration(～2 s) and high-intensity(～1250 W/cm2) heating scheme can completely reduce the cooling effect of the blood perfusion. The lesion shape and size were significantly altered by perfusion for split-focus pattern even with a rapid heating scheme when the focus spacing was larger than 2.4 mm. Underdosed areas might be present between two foci. Prolonging ex-posure time or shortening focus spacing can reduce the cool region between two foci. In addition,the influences of thermal and acoustic parameters were also studied. When the therapy depth is short(<5 cm) ,the lesion size monotonically increases with increasing attenuation coefficient that ranges from 5.4 to 11 Np/(m?MHz) .     

Comparison of laparoscopic hepatectomy,percutaneous radiofrequency ablation and open hepatectomy in the treatment of small hepatocellular carcinoma

Objective

Three mainstream techniques—laparoscopic hepatectomy (LH), percutaneous radiofrequency ablation (pRFA), and open hepatectomy (OH)—were compared in this study, in terms of their efficacies in the treatment of small hepatocellular carcinoma (HCC).

Methods

A comparative study was performed within a total of 94 patients diagnosed with small HCC in our hospital from 2005 to 2010, who underwent LH (28), RFA (33), or OH (33). They had either a single tumor lesion of less than 5 cm or up to three nodules with diameters of less than 3 cm each. Outcomes were carefully evaluated throughout a 3-year follow-up interval and statistically interpreted.

Results

The pRFA group had a significantly lower disease-free survival rate compared with the two surgical groups (P=0.001) and significantly shorter overall survival (P=0.005), while the LH group and the OH group had no difference in survival results. For patients younger than 60 years old, surgical approaches offered a better long-term overall survival prognosis (P=0.008). There were no statistically significant differences among the three groups in overall survival for elderly patients (P=0.104).

Conclusions

Among patients with small HCC, LH may provide better curative effects than pRFA without increasing complication rates. pRFA leads to faster recurrence than surgical resections. LH has similar therapeutic effects to OH and causes less trauma. For patients younger than 60 years old, LH may be the best curative treatment. Elderly patients may choose either surgery or pRFA.

     

High-intensity focused ultrasound with large scale spherical phased array for the ablation of deep tumors

et tissue by either moving single focal point or generating multiple loci simultaneously.