Objective To investigate the efficacy and safety of segmental electrical isolation of pulmonary veins (PVs) during atrial fibrillation (AF) Methods Nine patients were included, of whom 4 had recently persistent AF (3～4 months) and 5 suffored from paroxysmal AF occurred AF frequently We adopted one transseptal procedure Lasso mapping catheter and ablation catheter were positioned into target pulmonary vein ostium through the same site of atrial septum RF ablation was applied at the pulmonary vein potential (PVP) breakthrough using thermo control RF catheter during AF Results Twenty nine PVs were targeted for segmental RF ablation and isolated completely PVPs in target PVs were in higher spike and more frequent than left atrial potentials There were no complications associated with the procedure Seven patients were converted to sinus rhythm during the procedure Two patients restored sinus rhythm by cardioversion Conclusion It is suggested that the method of segmental PV isolation during AF is safe and has higher success rate It is not necessary to stop antiarrhymic drugs before RF ablation This study provides a reliable method for segmental electrical isolation of pulmonary veins in patients with persistent AF

Objective To analyze the electrophysiological characteristics of atrioventricular nodal reentrant tachycardia(AVNRT) requiring ablation at the mitral annulus.Methods Ablation was carried out at the mitral annulus by mapping the slow pathway with resetting method in order to acquire the electrophysiological parameters needed for successful ablation of AVNRT.Results Three cases with AVNRT who had prior failed ablation were successfully ablated by targeting the slow pathway located at the mitral annulus.The location of the left-sided slow pathway was selected by a positive resetting response and verified by junctional automaticity elicited by radiofrequency application and elimination of tachycardia.Conclusion AVNRT refractory to ablation of slow pathway at the posteroseptal area may require ablation at the mitral annulus.Resetting response may help to locate the slow pathway along the mitral annulus.

Objective To estimate whether a change in the polarity of low atrial electrograms recorded near the ablation line is an accurate indicator of complete isthmus block in the radiofrequency ablation of typical atrial flutter. Methods Radiofrequency ablation was performed in 10 patients with typical atrial flutter. Electrograms were recorded around the tricuspid annulus using a duodecapolar halo catheter and the distal electrode of halo catheter positioned just near the ablation line. The electrogram polarity of the distal electrode pair (H potential) was analyzed during atrial flutter and during coronary sinus pacing before and after ablation. Results Radiofrequency ablation was performed during coronary sinus pacing in 8 patients and performed during atrial flutter in 2 patients. Complete isthmus block was achieved in all patients. Before ablation, the initial polarity of H potential was predominantly positive during coronary sinus pacing and predominantly negative during atrial flutter. After complete isthmus block was achieved, the initial polarity of H potential was predominantly negative during coronary sinus pacing in all the patients. Conclusion The change of the electrogram polarity recorded just near the ablation line during coronary sinus pacing after ablation of typical atrial flutter is a simple, quick and accurate indicator of complete isthmus block.

Objective To investigate the efficacy and safety of the segmental electrical isolation of pulmonary veins (PVs) in patients with paroxysmal atrial fibrillation (PAF). Methods Thirty-nine patients (28 males, 11 females) with recurrent documented symptomatic PAF were included. In order to avoid the risk of cardiac tamponand, we adopted one transseptal procedure and obtained unselective angiography of all PVs and left atrial appendage using pigtail catheter. Lasso mapping catheter and ablation catheter were put into target pulmonary vein ostium through the same site of atrial septum. We routinely mapped the right inferior PV lest any pulmonary vein potential (PVP) that triggered PAF should be omitted. RF ablation was applied at the PVP breakthrough and slightly right and left by moving the RF catheter. Results Eighty-five PVs were targeted for segmental RF ablation. Eight-one were isolated completely. Immediate successful rate was 95%. There was not any complication associated with the procedure. Conclusion It is suggested that the method of segmental PV isolation has a higher cure rate and a shorter procedure time compared with other traditional methods. It can minimize the lesion of pulmonary veins and avoid PV stenosis.

0 05 There was 1 case of cardiac tamponand and 1 case of 60% stenosis of the left superior PV associated with the procedure Conclusion ERAF after segmental PV isolation is common, occurring in approximately 39% of patients with paroxysmal AF However, approximately 35% of ERAF patients without early repeat ablation have no further AF during long term follow up It is suggested that temporary antiarrhymic drug therapy may be more appropriate than early repeat ablation in patients with ERAF

Objective The aim of this study was to investigate the mechanisms and the possible treatment of early and frequent recurrence of atrial fibrillation after segmental pulmonary veins isolation (PVI) in patients with paroxysmal atrial fibrillation (AF). Methods and Results Guided by Lasso mapping catheter, segmental pulmonary veins isolation was performed using radiofrequency energy in 54 consecutive patients (mean age 53?15 years) with recurrent documented symptomatic paroxysmal AF. Early recurrence of AF and rapid atrial arrhythmia occurred in 10 out of 54 patients (18.5%) within two weeks after PVI. 4 out of 10 patients (7.4 %) experienced early and frequent recurrence of atrial fibrillation and atrial tachyarrhythmia, which we termed as “atrial arrhythmic storm". The 4 patients were treated with class Ⅰ and Ⅲ antiarrhythmic drugs for 3 months. The “atrial arrhythmic storm" subided apparently and disappeared within two weeks after antiarrhythmic drug therapy. Only 1 patient still suffered from paroxysmal AF after drug control at mean follow-up of 3 months. After repeat ablation, there was no occurrence of AF and atrial arrhythmia in this patient.Conclusion A few paroxysmal atrial fibrillation patients experienced “atrial arrhythmic storm" after segmental pulmonary veins isolation. It is suggested that “atrial arrhythmic storm" after PVI may due to a lot of factors and combined antiarrhythmic drug therapy may be feasible. Early repeat ablation in patients with “atrial arrhythmic storm" may not be necessary.

Objective To investigate the prognostic implications of the size of left atrium with catheter ablation of atrial fibrillation.Methods Forty-two consecutive patients with symptomatic and drug-refractory paroxysmal or persistent AF admitted from 2005 May to 2006 November were included in the present study.The mean age was 60?12 years and 25 patients(58%)were male.Paroxysmal AF was present in 37 patients(88%)and persistent AF in 5 patients(12%).A 3D electroanatomic map of the LA including the pulmonary vein(PV)ostia was constructed with a nonfluoroscopic navigation system(Carto,Biosense Webster).The left and right PVs were encircled by continuous radiofrequency ablation lines.The left atrial diameter(LAD)was measured by 2D-guided M-mode echocardiography,in terms of anteroposterior diameter,left-right diameter and superior-inferior diameter by ”Simpson” method.Left atrial volume(LAV)was calculated by ”Pumbo” method.Body surface area(BSA)(m2)was used for indexing body size variables.The respective formulae are:left atrial volume index(LAVI)=LAV/BSA(mL/m2);left atrial diameter index(LADI)=LAD/BSA.Results Fifteen patients(34%)suffered from recurrent AF after 3 months of follow up.The LAVI of the recurrent group of patients was(68.19?23.68)mL/m2 compared with that of the non-recurrent group of(52.07?17.34)ml/m2(P=0.019).Logistic regression analysis revealed LAVI was the only independent risk factor of recurrence(OR=1.04,95% CI 0.99-1.09,P=0.04).Age(P=0.806),sex(P=0.338),AF history(P=0.46),hypertension(P=0.963),LAD(P=0.41),LADI(P=0.093),LAV(P=0.471),LVEF(P=0.91)between the 2 groups had no statistic differences.Conclusion Left atrial volume index(LAVI)is a better parameter compared with LAD,LADI and LAV in reflecting the left atrial size.LAVI is an independent predictor of recurrence of AF after catheter ablation.We found that LAVI≥55 mL/m2 was the strongest predictor,independent of age and other clinical parameters.

Objective To investigate the influence of cervical vagosympathetic trunk or ganglionated plexi stimulation to the inducibility of atrial fibrillation(AF) in dogs.Methods In 16 anesthetized dogs,right cervical vagosympathetic trunk(VST) were dissected.A right thoracotomy was used to expose fat pad(FP) containing the ganglionated plexi(GP) at the caudal end of the sinus node.An electrode catheter was attached along the right superior pulmonary vein to allow programmed atrial pacing.At 2?,4? and 10? threshold atrial refractory periods(ARPs) were determined with and without VST or GP stimulation.At each pacing threshold AF inducibility was measured from the window of vulnerability(WOV).A cumulative WOV sum made of all WOVs was calculated in each group.Results In the baseline state the heart rate(HR) averaged 153?22 beats/min.Slowing of the HR by VST stimulation(79?44 beats/min) was not significantly different than with GP induced slowing(87?99 beats/min,P=NS).Furthermore,there were no significant differences between the lowest ARPs with VST stimulation and GP stimulation,accounting to 90?17 ms and 91?13 ms respectively(P=NS),but both are shorter than that in the baseline state,which was 101?20 ms(P

Objective To investigate electrophysiologic characteristics,the original site of atrial tachycardia(AT)and the results of radiofrequency catheter ablation(RFCA)in children without structural heart disease.Methods Electrophysiologic study and RFCA were performed in 46 children with AT.The site of origin of AT was mapped by using activation mapping during tachycardia.Magnetic electroanatomical mapping(CARTO system)for ablation of atrial tachycardia was performed in 4 patients.Preselecting a temperature of 50~60 ℃ was selected for ablation.Results Electrophysiologic study verified that the mechanism of all the tachycardias in 46 children was focal AT,which might be short paroxysmal,paroxysmal or persistent.1 child also had atrioventricular nodal reentrant tachycardia.ATs were successfully ablated in 41 children(89%),in which 39 had one original site(27 foci in right atrium and 12 foci in left atrium),2 had at least two original sites.Conclusion The success rate of RFCA in ATs of children without structural heart disease was relatively high.Atrial taclycardia could be eliminated by radiofrequency current with safety and efficacy.

Objective To identify the role of protein kinase C(PKC) activation in ischemic myocardium proctection and its effect after inhibition by polymyxin B sulfate.Methods We randomly divided 30 rabbits into ischemic(IS) group,ischemic preconditioning(IPC) group and polymyxin B sulfate(PMB) group.According to the method reported in previous literature,we simultaneously recorded ECG,pressure curve and monophasic action potential(MAP) throughout the ischemia and reperfusion perocess.Results The rabbit heart rates were not changed significantly during the ischemic or reperfusion period.The products of heart rate multiplying systolic pressure were significantly higher in IPC group compared with the other two groups(P