Objective To investigate the clinical and electrophysiological characters of atrial fibrillation(AF) originated from superior vena cava(SVC).Methods Patients with SVC-originated AF admitted into our centre during the past 2 years were retrospectively investigated,and their clinical and electrophysiological characters were systematically analyzed.Results The AF in 16 patients(M/F=12/4 cases,mean age of 53.4?10.6 years old,paroxysmal/persistent AF=11/5 cases) were confirmed to be originated from SVC,who contributed to 2.9%(16/545) of total cases underwent AF ablation during the same period.Among the 16 cases,2 patients were diagnosed as SVC-originated AF by surface ECG,and isolation of SVC terminated AF in these 2 patients.In the remaining 14 patients with non-classic surface ECG,AF or organized atrial tachycardia(Ata) still sustained after initial left atrial(LA) ablation.The sustainable AF and Ata were found to be driven by fast activations within SVC,and were terminated by isolation of SVC.The average applications and procedure time for isolating SVC were 6?2 times and 10?3 minutes respectively.The average muscle connections between SVC and LA were 3?1.After a mean period of 6-month-follow-up,only one patient recurred with organized Ata.Except femoral hematoma in one patient,no other complications were found.Conclusion In addition to pulmonary vein and LA,SVC could be the orgin of AF.Therefore,for patient with sustainable AF or organized Ata after initial LA ablation,SVC origin should be put under consideration.

BACKGROUND:Circumferential pulmonary vein antrum ablations guided by CARTO system or integration of a computed tomographic or magnetic resonance imaging scan (CARTO-Merge) are two main locating methods.Theoretically,CARTO-Merge provides a detailed appreciation of the pulmonary vein anatomy,however,whether it can improve the safety and success of catheter ablation of atrial fibrillation remains uncertainly.OBJECTIVE:To explore the effect of CT image integration into three-dimensional (3D) electroanatomical mapping system on clinical outcomes of catheter ablation of atrial fibrillation.DESIGN,TIME AND SETTING:The randomized contrast observation was performed at Department of Cardiology of Beijing Anzhen Hospital from October 2005 to May 2007.PARTICIPANTS:A total of 93 patients with drugs refractory,paroxysmal atrial fibrillation who underwent circumferential pulmonary vein antrum ablation.METHODS:All patients underwent circumferential pulmonary vein antrum ablation using irdgated radiofreguency ablation with the endpoint of electrical isolation.Ablation was guided by 3D mapping alone in 50 patients (CARTO group) or by CT image integration in 43 patients (CARTO-Merge group).MAIN OUTCOME MEASURES:Procedure-related parameters,such as procedure duration,fluoroscopy duration,cumulative success rate and complication,were compared between the two groups.RESULTS:Pulmonary veins were isolated in all patients.After (12.6±2.9) months follow-up,73 (78.5%) patients did not have recurrence of atrial fibrillation at 3 month after the procedure.The fluoroscopy time in CARTO group was significant longer than that in CARTO-Merge group (P<0.05).The mean procedure duration,radiofrequency ablation duration,procedure-related complication and cumulative success rate were comparable between the 2 groups.CONCLUSION:Circumferential pulmonary vein antrum ablation guided by 3D mapping alone or by CT integration had similar safety and success rate in paroxysmal atrial fibrillation patients.But CT integration,which facilitated to a detailed representation of the anatomy of left atrium,is associated with reduced fluoroscopy duration.

Objective To evaluate the feasibility and effect of three-points ablation approach in in treatment of typical atrial flutter guided by CARTO. Methods Twenty-six patients with typical atrial flutter diagnosed by ECG and electrophysiological study (EPS) were enrolled in this study. Activation sequence mapping and linear ablation were performed in 11 patients (conventional group) . Three-points guided linear ablation with CARTO system was performed in another15 patients (three-points group) . Results There was no significant difference in the success rate between the two groups. Both the procedure and fluoroscopic time in three-points group were significantly shorter than that in conventional group [(72.66±29.82) vs (102.52±32.61) min;(4.26±2.76) vs (7.32±3.16) min] . Conclusions The three-points ablations approach is as safe and effective as conventional ablation approach in treatment of typical atrial flutter;however,the former can significantly shorten the procedure time and fluoroscopy time.

Objective To evaluate the feasibility of catheter ablation of Para-Hisian Atrial Tachycardia guide by CARTO. Method Catheter ablation guided by CARTO was performed after activation map in three patients with Para-Hisian Atrial Tachycardia. Result Successful ablation was got at right atrial in two patients and at non-coronary in one patient. Conclusion Catheter ablation guided by CARTO is safe and efficient for Para-Hisian Atrial Tachycardia.

Objective To study different effects of control heart rhythm by radiofrequency catheter ablation and control heart beat by drugs on quality of life in patients with paroxysmal atrial fibrillation. Methods Sixty patients with paroxysmal atrial fibrillation were divided into two groups,radiofrequency catheter ablation group and heart beat control group. Quality of life grades were calculated in each group according to SF - 36. Results Quality of life grades were significantly higher in radiofrequency catheter ablation group than heart beat control group. Conclusions Radiofrequency catheter ablation can improve quality of life than heart beat control therapy in patients with paroxysmal atrial fibrillation.

Objective To investigate the effect of thyroxine replacement therapy with residual subclinical hypothyroidism on the success rate of catheter ablation in elderly patients with atrial fibrillation(AF).Methods Among the consecutive patients with AF who underwent a first AF ablation in our center between 2009 and 2012,we identified 56 patients(41 paroxysmal AF,15 persistent AF)with subclinical clinical hypothyroidism after receiving thyroid hormone replacement therapy as study group.The control group consisted of 56 patients with euthyroidism and no history of thyroid dysfunction.All patients underwent catheter ablation.Results At the end of follow up,37.5%(21/56)patients were AF free after the first procedure in the study group,in comparison to 64.3%(36/56)in control group(χ2=8.655,P=0.003).Last procedure was performed in 27 patients of study group and in 15 patients of control group.After the last performed ablation,62.5%(35/56)study group patients and 80.4%(45/56)controls group patients had no recurrence(χ2=4.653,P=0.031).The major complications rate did not differ between two groups(P=0.642).Conclusions Thyroid hormone replacement therapy with residual subclinical hypothyroidism reduces catheter ablation success rate in elderly patients with atrial fibrillation.

Objective To evaluate the clinical efficacy and safety of catheter ablation for atrial fibrillation in elderly patients.Methods From September 2008 to October 2011,a total of 420 consecutive patients undergoing catheter ablation of atrial fibrillation (AF) were selected.The patients were divided into 3 age groups:30 59 yr group (n=279),60-74 yr group (n=100),and 75-87 yr group (n =41).The effect of operation and complications during operative and postoperative periods were evaluated.Patients were followed up for at least 6 months,and the rate of atrial fibrillation reocurrence and life quality were recorded.Results Among 480 catheter ablation procedures,in 7 (1.5％) patients occurred main complications,while in 5 (1.0％) patients appeared other complications.The incidence of main complications in 3 groups were 1.1％ (3 patients),2.0％ (2 patients) and 4.9％ (2 patients) respectively,other complication rates in 3 groups were 0.7％ (2 patients),1.0％ (1 patient) and 4.9％ (2 patients) respectively and there were no differences between groups (all P＞0.05).During follow-up,the cases without AF relapse were 68.5％ (191 patients),66.0％ (66 patients) and 57.1％ (23 patients) respectively,and the patients with AF paroxysm were 21.1％ (59 patients),21.0％ (21 patients),29.3％ (12 patients) respectively,and there was no significant difference between groups (all P＞0.05).And no difference was found in improvement degree of life quality among three groups (P＞0.05).Conclusions Catheter ablation is safe and effective in elderly patients.For patients over 75 years with many types of cardiovascular diseases,catheter ablation is effective to control the relapse of AF,can significantly improve the quality of life,and has no increased risk of complications.

Objective To identify the electrophysiological charateristics and cause of ridge gap related reentry after MI ablation in atrial ifbrillation patients. Methods Activation and entrainment mapping was performed in 82 redo cases for OAT recurrence in whom MI was ablated during the index produre. Once ridge gap related reentry was conifrmed, detailed mapping was performed in MI and ridge region. In addition, in 36 cases undergoing MI ablation and fulfilling criterion for bidirectional block, differential pacing was repeated at the ridge to identify a ridge gap. Results Out of 82 redo cases for OAT recurrence in whom MI was ablated during the index produre, 7 (8.5%) was found to be ridge gap related reentry. TCL was (247.9±19.2) ms, and the left atrial endocardial activation time was (145.4±17.7) ms, accounting for (58.5±3.2)%of TCL. However, wide double potential was recorded along the previous ablated MI line where PPI was (34.3±6.6) ms longer than TCL, while PPI was signiifcantly shorter at the ridge[PPI-TCL (11.4±3.9) ms, P<0.001]. Tachycardia was terminated at the ridge in 6 cases and at the corresponding site in coronary sinus in 1 case. No recurrence was found during follow-up for (11.1±4.5) months. In addition, in 36 patients undergoing MI ablation in whom criterion of bi-directional block was fuliflled, conduction gap located at the ridge was found in 5 (13.9%) cases. Conclusions MI ridge gap related reentry is a distinctive OAT, in which the ridge was used as the critical isthmus, whereas the previous ablated MI line is not part of the reentry. MI pseudo-block due to the ridge gap may lead to this type of recurrent tachycardia.

Objective To observe the management and outcome of the cardiac tamponade patients during the ablation procedure using two different anticoagulation strategies. Methods All the patients developed tamponade during the ablation procedure were enrolled from January 2007 to December 2013 in our center. In group 1, warfarin was discontinued 3 to 5 days before the procedure and low molecular weight heparin (LMWH) was administered subcutaneously until ablation procedure day. In group 2, warfarin was not discontinued and the international normalized ratio INR was to maintained between 2 and 3. Results There were 27 patients (0.6%) developed cardiac tamponade out of a total 4487 patients received ablation in our center. The baseline clinical characteristics including age, left atrium, the heparin dose and ACT during the procedure had no signiifcant difference between the groups, except that the INR was higher in the group 2 (0.9±0.1 vs. 2.3±0.5, P<0.001). There was no signiifcant difference in the amount of pericardiac drainage between the two groups (365±222 ml vs. 506±300 ml, P=0.137). Two patients in group 1 patient (11.1%) and 1 in group 2 (11.1%) needed emergency surgical repair (P>0.999). The median hospital day was similar in the 2 groups [(9.6±3.3) d vs. (12.1±4.5) d, P=0.167]. There were no other serious complications and no hospital death. Conclusions Non-discontinuation of warfarin during peri-procedural catheter ablation of AF is not signiifcantly different to bridging with LMWH in the management and outcome of acute cardiac tamponade.

Objective Identify the mechanism of induced atrial arrhythmias after pulmonary vein isolation (PVI) in patients with paroxysmal atrial ifbrillation(PAF), and investigate its long-term prognosis. Methods All patients with PAF undergoing PVI and induction test afterwards between Feburary 2010 and October 2010 were included. The induction protocol was rapid pacing initiated at cycle length of 250 ms with progressive shortening in a decrement of 10 ms down to 180 ms or refractoriness. Isoproterenol of 2-4μg/min was administrated as well. Inducibility was deifned as induction of atrial arrhythmia lasting >1 min. The mechanism of induced tachycardia was identiifed by activation mapping and entrainment mapping under the guidance of CARTO system. All patients were followed up by 36 months. Results Forty-nine atrial tachycardia were induced in 39 (19.7%) patients, including 35 organized atrial tachycardia (OAT) and 14 atrial ifbrillation (AF). The LA diameter was signiifcantly larger in inducible group than non-inducible group (39.5±6.6 mm vs. 36.7±5.2 mm, P=0.004). Macroreentry was the most common mechanism in induced OATs (28, 80.0%), and mitral isthmus was the most common critical site (20, 40.8%), followed by cavo-tricuspid isthmus (12, 24.5%), PV (6, 12.2%), LA septum (4, 8.2%), superior vena cava (3, 6.1%) and LA roof (1, 2.0%). Conclusions The most common mechanism of induced tachycardia by IV isoproterenol and rapid pacing is MI and CTI dependent after PVI in PAF patients, which can be succssefully eliminated by liner ablation, not increasing long-term recurrence rate.