Primary closed cooled tip ablation of typical atrial flutter in comparison to conventional radiofrequency ablation.

The purpose of this prospective, non-randomized study was to investigate the effectiveness of cooled radiofrequency ablation (cRFA) compared with conventional radio-frequency application (RFA) for ablation of typical atrial flutter (AF). Methods Isthmus ablation was carried out using a system with a circulating fluid path through the ablation tip to control tip temperature in 100 patients with AF. Thirty consecutive AF patients underwent conventional RFA. The number of applications for cRFA was 13.7 +/- 6.9 and for RFA 24.0 +/- 14-5 (P<0.0007) at powers between 35 and 50 W and a tip temperature range of 38-43 degrees C. Ablation duration and fluoroscopy time were 9-9 +/- 4.9 and 22-8 +/- 10.7 min for cRFA, respectively. In contrast, for RFA, ablation duration and fluoroscopy time were 20-6 +/- 14.2 (P<0.0001) and 27.4 +/- 12.7 min, respectively. In 93% of the cooled tip group and in 80% of the control group bi-directional block was confirmed. At 6-months follow-up, recurrence rates were 9 in the cooled-tip group and 7 in the control group, corresponding 10.4% and 25.9%. There were no significant complications. Compared with RFA, cRFA requires lower application numbers. Recurrence rates are low and the overall success rate is high.     

射频消融治疗早期肝癌的荟萃分析

目的 根据现有的临床研究资料评价射频消融(RFA)治疗早期肝癌的疗效与安全性.方法 检索Cochrane图书馆、EMBASE、PubMed、OVID等数据库和中国期刊网中的随机对照试验(RCT)文献,将Jadad评分≥3分的高质量论文纳入研究,并提取纳入研究的特征信息.采用STATA9.0软件进行数据分析,首先进行异质性检验,根据异质性检验结果选择相应的效应模型.然后进行敏感性分析,并以漏斗图和Egger回归方程评定有无发表偏倚.结果 共6篇RCT文献纳入本研究,共包含862例早期肝癌患者.研究表明与其他治疗方法相比,RFA治疗可明显增加早期肝癌患者的3年生存率,并减少了肝内局部复发率,OR值分别为2.06(95%CI为1.54～2.77,P=0.000)和0.40(95%CI为0.28～0.57,P=0.000);而在肝内转移、远处转移、严重副作用等方面差异无统计学意义.漏斗图基本呈现下宽上窄左右对称的图形,Egger线性回归显示3年生存率、肝内局部复发率、肝内转移、远处转移、严重副作用等方面的P值分别为0.670、0.160、0.884、0.087、0.317,提示无发表偏倚.结论 早期肝癌经RFA治疗可获得优于其他疗法的局部疗效和3年生存率.RFA具有微创、简便和经济的优点,有可能作为早期肝癌的首选治疗手段之一.     

Bipolar radiofrequency ablation of liver metastases during laparotomy. First clinical experiences with a new multipolar ablation concept

Background and objective Radiofrequency ablation (RFA) is a promising method for local treatment of liver malignancies. Currently available systems for radiofrequency ablation use monopolar current, which carries the risk of uncontrolled electrical current paths, collateral damages and limited effectiveness. To overcome this problem, we used a newly developed internally cooled bipolar application system in patients with irresectable liver metastases undergoing laparotomy. The aim of this study was to clinically evaluate the safety, feasibility and effectiveness of this new system with a novel multipolar application concept.Patients and methods Patients with a maximum of five liver metastases having a maximum diameter of 5 cm underwent laparotomy and abdominal exploration to control resectability. In cases of irresectability, RFA with the newly developed bipolar application system was performed. Treatment was carried out under ultrasound guidance. Depending on tumour size, shape and location, up to three applicators were simultaneously inserted in or closely around the tumour, never exceeding a maximum probe distance of 3 cm. In the multipolar ablation concept, the current runs alternating between all possible pairs of consecutively activated electrodes with up to 15 possible electrode combinations. Post-operative follow-up was evaluated by CT or MRI controls 24–48 h after RFA and every 3 months.Results In a total of six patients (four male, two female; 61–68 years), ten metastases (1.0–5.5 cm) were treated with a total of 14 RF applications. In four metastases three probes were used, and in another four and two metastases, two and one probes were used, respectively. During a mean ablation time of 18.8 min (10–31), a mean energy of 48.8 kJ (12–116) for each metastases was applied. No procedure-related complications occurred. The patients were released from the hospital between 7 and 12 days post-intervention (median 9 days). The post-interventional control showed complete tumour ablation in all cases.Conclusions Bipolar radiofrequency using the novel multipolar ablation concept permits a safe and effective therapy for the induction of large volumes of coagulation in the local treatment of liver metastases.     

Major complications after radiofrequency ablation for liver tumors： Analysis of 255 patients

AIM： To investigate the major complications after radiofrequency ablation （RFA） for the treatment of liver tumors and analyze possible risk factors that precipitate these complications.
METHODS： From March 2001 to April 2008, 255 patients with liver tumors （205 male, 50 female; age range, 18-89 years; mean age, 56.0 years） who received RFA were enrolled in this study. Of these patients, 212 had hepatocellular carcinoma, 39 had metastatic liver tumors and four had cholangiocellular carcinoma. One hundred and forty eight patients had a single tumor, and 107 had multiple tumors. Maximum diameter of the tumors ranged 1.3-20 cm （mean, 5.1 cm）. All patients were treated with a cooledtip perfusion electrode attached to a radiofrequency generator （Radionics, Burlington, MA, USA）. RFA was performed via the percutaneous approach （n = 257）, laparoscopy （n = 7）, or open surgical treatment （n = 86）. The major complications related to RFA were recorded. The resultant data were analyzed to determine risk factors associated these complications.
RESULTS： Among the 255 patients, 425 liver tumors were treated and 350 RFA sessions were performed. Thirty-seven （10%） major complications were observed which included 13 cases of liver failure, 10 cases of hydrothorax requiring drainage, three cases of tumor seeding, one case of upper gastrointestinal bleeding, one case of intrahepatic abscess, one case of bile duct injury, one case of cardiac arrest, and five cases of hyperglycemia. Seven patients had more than two complications. Liver failure was the most severe complication and was associated with the highest mortality. Eleven patients died due to worsening liver decompensation. Child-Pugh classification （P = 0.001） and choice of approach （P = 0.045） were related to post-treatment liver failure, whereas patient age, tumor size and number were not significant factors precipitating this complication.
CONCLUSION： RFA can be accepted as a relatively safe procedure for the treatment of liver tumors. However, attention should be paid to possible complications even though the incidences of these complications are rare. Careful patient selection and the best approach choice （percutaneous, laparoscopy, or laparotomy） will help to minimize the incidence and morbidity rate of complications which occur after RFA.     

Treatment efficacy of radiofrequency ablation of 338 patients with hepatic malignant tumor and the relevant complications

AIM: To investigate the treatment efficacy of radiofrequency ablation (RFA) of hepatic malignant tumor and the relevant complications. METHODS: A total of 338 patients with 763 hepatic tumors underwent ultrasound-guided RFA (565 procedures). There were 204 cases of hepatic cellular carcinoma (HCC) with 430 tumors, the mean largest diameter was 4.0 cm. Of them, 48 patients (23.5%) were in stages Ⅰ-Ⅱ (UICC Systems) and 156 (76.5%) in stages Ⅲ-Ⅳ There were 134 cases of metastatic liver carcinoma (MLC), with 333 metastases in the liver, the mean diameter was 4.1 cm, the liver metastases of 96 patients (71.6%) came from gastrointestinal tract. Ninety-three percent of the 338 patients were treated using the relatively standard protocol. Crucial attention must be paid to monitor the abnormal changes in ultrasound images as well as the vital signs of the patients to find the possible hemorrhage and peripheral structures injury in time. The tumors were considered as ablated completely, if no viability was found on enhanced CT within 24 h or at 1 mo after RFA. These patients were followed up for 3-57 mo. RESULTS: The ablation success rate was 93.3% (401/430 tumors) for HCC and was 96.7% (322/333 tumors) for MLC. The local recurrence rate for HCC and MLC was 7.9% (34/430 tumors) and 10.5% (35/333 tumors), respectively. A total of 137 patients (40.5%) underwent 2-11 times of repeated ablations because of tumor recurrence or metastasis. The 1st, 2nd, and 3rd year survival rate was 84.6%, 66.6%, and 63.1%, respectively; the survival rate from 48 patients of Ⅰ-Ⅱ stage HCC was 93.7%, 80.4%, and 80.4%, respectively. The major complication rate in this study was 2.5% (14 of 565 procedures), which consisted of 5 hemorrhages, 1 colon perforation, 5 injuries of adjacent structures, 2 bile leakages, and 1 skin burn. CONCLUSION: RFA, as a minimally invasive local treatment, has become an effective and relatively safe alternative for the patients of hepatic malignant tumor, even of advanced liver tumor, tumor recurrence, and liver metastases. Knowledge about possible complications and their control may increase the treatment efficacy and help to promote the use of RFA technique.     

Unexplained liver laceration after metastasis radiofrequency ablation

Many studies have established the role of radiofrequency (RF) ablation as a minimally invasive treatment for liver metastases. Although relatively safe, several complications have been reported with the increased use of RF ablation. We describe here a case of unexplained liver laceration after a RF procedure. A woman who presented a solitary metachronous liver metastasis underwent RF ablation treatment for this lesion. Six hours later the patient displayed fatigue and pallor.Emergency blood tests showed a haemoglobin level of < 7 g/dL and markedly elevated transaminase levels.A computed tomography examination revealed two areas of liver laceration with haematoma, one of them following the path of the needle and the other leading away from the first. Following a blood transfusion, the patient was haemodynamically stable and completely recovered 24 h later. The patient remained in bed for 1 wk. No surgical intervention was required, and she was discharged 1 wk later.     

Cryoballoon ablation versus radiofrequency ablation for atrial fibrillation

Catheter ablation (CA) provides the most effective treatment option for patients suffering from symptomatic atrial fibrillation (AF). The procedural cornerstone of all ablation strategies and for all entities of AF is the electrical isolation of the pulmonary veins (PV). CA with the use of radiofrequency (RF) in conjunction with a 3-dimensional electroanatomical mapping system is the most established ablation approach, but it demands a long learning curve and recurrences of AF are commonly the result of recovered PV conduction. As a consequence, novel ablation systems such as the Cryoballoon (CB) have been evolved aiming at facilitation and increased efficacy of pulmonary vein isolation (PVI). CB ablation is characterized by a short learning curve as well as short procedure times and demonstrated non-inferiority with regard to safety and efficacy when being directly compared to RF ablation for treatment of paroxysmal AF. However, RF ablation is first choice for treatment of persistent AF, in particular when expanded ablation strategies beyond PVI are intended in order to improve clinical outcomes.     

心房颤动射频消融术后远程心电监测随访的意义

目的通过电话心电远程监测心房颤动（房颤）射频消融术后复发情况,探讨远程心电监测仪诊断心律失常的临床价值。方法自2009年10月至2010年4月在我院行房颤射频消融术患者72例,其中持续性房颤39例、阵发性房颤33例。患者在消融术后第1天及每3个月均接受24h动态心电图检查,同时术后每天定时及有症状时接受电话远程传输心电图（TTECG）监测。比较两种检测方法记录的房颤复发情况及房颤发生与症状的相关性。结果随访（11．0±2．3）个月,TTECG共检测到4403份无干扰心电图,3610份窦性心电图中有症状的1351份（37．43％）。793份异常心电图中无症状性发作的214份（26．99％）。术后3个月空白期中,24h动态心电图发现17例（23．61％）房颤复发,TrECG发现31例复发,差异有统计学意义（P=0．004）。随访期间,24h动态心电图发现9例房颤患者复发,TTECG发现18例复发,差异有统计学意义（P=0．033）。通过TTECG的监测,与空白期的复发率比较,1年后房颤复发率明显下降（P=0．022）,而24h动态心电图未发现复发率的差异（P=0．083）。通过24h动态心电图及TTECG监测,持续性房颤消融成功率分别为84．62％,71．79％（P=0．000）,阵发性房颤消融成功率分别为90．91％,78．79％（P=0．006）。结论对于心律失常尤其是射频消融术后房颤的监测,电话远程心电监测优于常规24h动态心电监测,能及时发现术后房性心律失常复发,尤其是无症状性房颤。术后有症状患者也不一定是真正的房颤复发,实际为窦性心律。     

Radiation exposure to patient and operator during radiofrequency ablation for supraventricular tachycardia

Abstract Background: Radiofrequency (RF) ablation has become the primary method of treatment for supraventricular tachycardia and often requires prolonged fluoroscopy times. Aim: To quantitate radiation exposure to patient and operator during RF ablation for supraventricular tachycardia. Methods: Thermoluminescent dosemeters were used to monitor radiation at seven sites. Positions were: patient's thyroid, left scapula, T9 vertebra, right scapula and L4-L5 vertebra and the operator's thyroid and left hand. Monitoring was performed during 22 procedures. Of the patients studied 10 (45%) had atrioventricular junctional re-entry tachycardia (AVJRT) and 12 (55%) had accessory pathway tachycardia. Results: The median fluoroscopy times (minutes) and inter-quartile ranges were 46 (39–65) for AVJRT, 55 (52–60) for left free wall accessory pathway (LFW), 107 (89–140) for septal and 166 (128–176) for RFW pathways. The mean radiation doses (mGy) to the chest wall were 50 for AVJRT, 47 for LFW, 87 for septal and 151 for RFW pathways. The mean radiation to the chest wall of the patient per case was found to be 3.9 times that reported for diagnostic cardiac catheter-isation and 1.5 times that reported for angioplasty. Conclusions: Radiofrequency ablation is associated with significant irradiation of the patient and operator. All precautions should be taken to decrease this exposure. If eye irradiation is assumed to be equal to that to the thyroid, more than 45 procedures per month by a single operator (using ceiling-suspended lead glass shielding) may result in exceeding the recommended dose limit to the eye. (Aust NZ J Med 1995; 25; 490–495.)     

射频消融治疗儿童快速心律失常的并发症分析

目的　总结射频消融治疗儿童快速心律失常出现并发症的防治经验和教训。方法　射频消融(RFCA)治疗160例患儿中发生并发症9例,发生率为5.6%,其中股动脉血栓5例(3.1%),血气胸并失血性休克、心包积液、中度主动脉瓣反流(AR)和三度房室传导阻滞各1例(0.62%)。及时分别通过动脉溶栓、输血、胸腔闭式引流、埋置永久起搏器等方法进行处理。结果　AR经药物治疗,反流程度减轻,其余经治疗后痊愈。结论　射频消融治疗儿童快速心律失常并发症比成人发生率高,与儿童心血管的解剖结构、使用成人的射频导管和电极、操作经验不足有关,严格操作规程,使用儿童的射频导管和电极,丰富的射频导管操作经验、心电生理学和影像学知识、能使并发症减少到最低限度。     

Endoscopic management of an esophagopericardial fistula after radiofrequency ablation for atrial fibrillation

A case is reported of a 76-year-old man with a past history of atrial fibrillation. A radiofrequency ablation procedure was suggested following several failed cardioversion attempts. However, an esophagopericardial fistula complicated the procedure. This life-threatening complication was successfully managed using both the placement of a covered esophageal stent and surgical pericardial and mediastinal drainage. In fact, no persisting fistula could be detected when the esophageal stent was removed seven weeks later. Atrioesophageal and esophagopericardial fistulas are two of the most severe complications associated with cardiological radiofrequency ablation procedures. They are responsible for majority of the deaths associated with this procedure. Despite the extremely high morbimortality associated with cardiothoracic surgery in such conditions, this treatment is the gold-standard for the management of such complications. This case report emphasizes the importance and efficacy of the endoscopic approach as part of a multidisciplinary management approach to this serious adverse event following radiofrequency ablation for atrial fibrillation.     

Therapeutic effectiveness of echo-guided percutaneous radiofrequency ablation therapy with a LeVeen needle electrode in hepatocellular carcinoma

AIM:To investigate the results of radiofrequencyablation(RFA)in obtaining the necrosis of hepatocellularcarcinoma(HCC)in cirrhotic patients and to assessthe results of RFA in relation to recurrence of HCC andsurvival of the treated patients.METHODS:Fifty-six consecutive cirrhotic patients with63 HCCs were treated with RFA between May 2000 andMay 2004.The diameter of the HCCs ranged from 1 cmto 5 cm(mean 2.8 cm).In all cases RFA was performedwith percutaneous approach under ultrasound guidanceusing expandable needle electrode(LeVeen needle).Treatment efficacy and recurrence were evaluated withdual-phase spiral computed tomography(CT).RESULTS:Complete necrosis after single or multipletreatment was achieved in 96.8%(61/63)tumors.We observed recurrence after complete necrosis in 23patients(41%)during a mean follow-up of 32.3 months.The recurrences were local in 2 patients(8.6%)and indifferent segments in 21(91.4%).Major complicationsoccurred in 3 patients(4%).During follow-up period,32(57.1%)patients died;15 due to progression of HCC,11 from liver failure,3 from esophageal varices bleedingand 3 from the causes not related to liver disease.CONCLUSION:RFA with LeVeen needle is an effectiveand safe treatment for HCC<5 cm in cirrhotic patients.It has yet to be established how far this treatmentinfluences the survival rate of patients.It becomesimportant to establish treatments to prevent recurrencesin different segments,such as interferon therapy.     

腹腔镜射频消融治疗乙型肝炎肝硬化并发小肝癌

目的探讨腹腔镜射频消融（LRFA）治疗小肝癌的可行性、安全性及疗效。方法采用LRFA法治疗8例乙型肝炎肝硬化并发小肝癌患者,共9个瘤体,肿瘤均位于肝脏表面、肝左外叶、近膈顶或邻近胆囊等空腔脏器。肝功能均为ChildA或ChildB级。结果所有患者均顺利完成手术,均未中转开腹,未出现大出血、胆道、膈肌及胃肠道灼伤等并发症;术后一月行影像学检查发现肿瘤坏死率为88．9％（8／9）,平均随访13．5个月,均未出现复发及转移。结论LRFA治疗小肝癌安全、有效,并发症少。     

Life-threatening hemorrhage after liver radiofrequency ablation successfully controlled by transarterial embolization

A 59-year-old man underwent liver radiofrequency ablation under laparotomy for recurrent hepatic carcinoma located in the caudate lobe,however,near-fatal bleeding occurred 1 wk after the operation.The intraoperative ultrasound study during laparotomy revealed left hepatic artery pseudoaneurysm.Suture and packing with ribbon gauze was used to obtain hemostasis.A secondary hemorrhage followed 11 h later and hepatic angiography was performed immediately.Bleeding from the pseudoaneurysm in a branch of the left hepatic artery was found and the artery branch was embolized with coils.Other than slight bile leakage,post-embolization continued satisfactorily.Bleeding did not reoccur.The follow up visit 1 mo later found the pseudoaneurysm disappearing and no tumor recurrence.     

Radiologic-pathologic correlation of three-dimensional shear-wave elastographic findings in assessing the liver ablation volume after radiofrequency ablation

AIM: To evaluate the usefulness of three-dimensional (3D) shear-wave elastography (SWE) in assessing the liver ablation volume after radiofrequency (RF) ablation.METHODS: RF ablation was performed in vivo in 10 rat livers using a 15-gauge expandable RF needle. 3D SWE as well as B-mode ultrasound (US) were performed 15 min after ablation. The acquired 3D volume data were rendered as multislice images (interslice distance: 1.10 mm), and the estimated ablation volumes were calculated. The 3D SWE findings were compared against digitized photographs of gross pathological and histopathological specimens of the livers obtained in the same sectional planes as the 3D SWE multislice images. The ablation volumes were also estimated by gross pathological examination of the livers, and the results were then compared with those obtained by 3D SWE.RESULTS: In B-mode US images, the ablation zone appeared as a hypoechoic area with a peripheral hyperechoic rim; however, the findings were too indistinct to be useful for estimating the ablation area. 3D SWE depicted the ablation area and volume more clearly. In the images showing the largest ablation area, the mean kPa values of the peripheral rim, central zone, and non-ablated zone were 13.1 ± 1.5 kPa, 59.1 ± 21.9 kPa, and 4.3 ± 0.8 kPa, respectively. The ablation volumes depicted by 3D SWE correlated well with those estimated from gross pathological examination (r² = 0.9305, P = 0.00001). The congestion and diapedesis of red blood cells observed in histopathological examination were greater in the peripheral rim of the ablation zone than in the central zone.CONCLUSION: 3D SWE outperforms B-mode US in delineating ablated areas in the liver and is therefore more reliable for spatially delineating thermal lesions created by RF ablation.     

Left main coronary thrombosis: unusual complication after radiofrequency ablation of left accessory atrioventricular pathway

Radiofrequency ablation (RFA) has established itself as a first-line therapy for the curative treatment of many patients with supraventricular or atrioventricular tachycardias and has exhibited a generally low incidence of serious sequelae (N Engl J Med. 1991;324:1612; Lancet. 1991;337:1557). Coronary artery injury is a rare complication. We present a patient with an acute thrombotic total occlusion of the left main coronary artery immediately after the end of RFA who was successfully treated with emergency percutaneous transluminal coronary angioplasty. This case illustrates an unusual coronary complication of RFA and serves as an exceptional example of survival with a good short-term prognosis after this unusual etiology of myocardial infarction.     

射频联合亚砷酸治疗兔肝VX2肿瘤的疗效观察

射频（RFA）是肝癌治疗的一种新手段，疗效确切。临床研究发现，对于直径大于5cm的恶性肿瘤治疗不彻底是RFA所面临的一大难题。我们采用射频联合亚砷酸局部治疗兔肝VX2肿瘤，通过观察肿瘤体积、转移和荷瘤兔存活时间的影响探讨联合治疗的安全性及高效性。     

Contrast-enhanced 3D ultrasound in the radiofrequency ablation of liver tumors

Liver metastases and hepatocellular carcinomas are two of the most common causes of cancer deaths in the world. Radiofrequency ablation （RFA） is a well recognized, effective and minimally invasive means of treating malignant hepatic tumors. This article describes the use of contrast-enhanced 3D ultrasound （CE-3DUS） in the staging, targeting and followup of patients with liver tumors undergoing RFA. In particular, its value in the management of large hepatic lesions will be illustrated. Current limitations of CE-3DUS and future developments in the technique will also be discussed. In summary, CE-3DUS is useful in the RFA of liver tumors with improved detection and display of occult lesions and recurrence, in the assessment of lesional geometry and orientation for a more accurate planning and guidance of multiple RFA needle electrodes in large tumors and in the evaluation of residual or recurrent disease within the immediate and/or subsequent follow-up periods.     

Catheter ablation of the atrioventricular node using radiofrequency energy

Background: Catheter ablation of the atrioventricular (AV) junction using stored direct current (DC) energy from a standard DC Cardioverter defibrillator was first reported in 1982. Since then many patients have been treated using this procedure for refractory supraventricular arrhythmias, usually atrial fibrillation and flutter. Undesirable thermal effects such as barotrauma and arcing are largely responsible for complications associated with the use of DC energy. This report details our experience of catheter ablation of the AV junction using radiofrequency (RF) energy in a series of 30 consecutive patients. Methods: RF ablations were performed using steerable Mansfield (Webster Laboratories) 4 mm tipped electrodes and locally assembled RF energy delivery system. Results: The procedure was successful in 27/30 (90%) patients using RF energy, while three patients required DC energy to achieve successful AV junction ablation. General anaesthesia was required in nine patients, six of whom required this for cardioversion to sinus rhythm so that an adequate His Bundle spike could be recorded and three for DC ablation. Dual chamber permanent pacemakers with automatic mode switching were implanted in four patients who had paroxysmal atrial fibrillation or flutter and the remainder had ventricular rate responsive pacemakers. Conclusions: In patients with drug refractory paroxysmal atrial fibrillation and flutter and in patients with established atrial fibrillation where control of the ventricular rate is difficult, catheter ablation of the AV junction using RF energy is a safe and effective procedure with a high success rate.