| BackgroundParoxysmal atrial fibrillation (AF) could be initiated by spontaneous discharges stemming from the pulmonary veins (PVs), which led to the development of segmental ostial ablation to isolate PVs, and continuous circular lesions around PVs. Pulmonary vein isolation at the junction between the PVs and the left atrium (LA) could cure AF. An encircling isolation of the ipsilateral PVs (EIPVsl) may be more effective to isolate the PV carina than individual PV isolation.Bidirectional block of the PV-LA junction can reduce the PV reconnection and may reduce the recurrence in AF patients undergoing circumferential PV isolation. It was relatively easy to determine the entrance conduction block, that was the PVPs disappeared or escaped beats appeared in the sinus or atrial fibrillation rhythm. Whether the pace-making rhythm captured relevant PVs was crucial. Even if the PV was captured, and it had nothing to do with the atrial activation sequence, it could belong to a successful exit block. The ideal endpoint was all four PV potentials disappeared, as absolute success; then, any PVP still appeared but delayed in more than30ms could be regarded as relative success. It ended up in failure as long as one of the four PVPs delayed in less than30ms.ObjectiveTo study the effect of different endpoints of ablation on the medical prognosis of AF patients.MethodsStudy population The population of the retrospective cohort study came from137patients of symptomatic AF between June2008and August2012, including113paroxysmal ones and24persistent ones. They had been informed of the surgical risk and signed consent forms.GroupingThe113paroxysmal AF patients were divided into two groups with recurrence and non-recurrence according to whether ones with recurrence post-operation or not. In accordance with the different endpoints after ablation, the92paroxysmal AF were divided into two groups: one group with all PVPs disappeared in36patients, another group with any time of PVPs delayed more than30ms in56ones.Encircling isolation of ipsilateral pulmonary veinsThe procedure was performed under local anesthesia and with Seldinger vascular puncture. During left subclavian venous puncture, a multielectrode catheter was placed in the coronary sinus (CS). After twice interatrial septum puncturing by X-ray fluoroscopy, two SWARTZ sheath tubes were placed in the LA. All PVs were marked on the3D map based on venography, and the LA reconstruction was obtained by the3D electroanatomic mapping system (CARTO, Biosense-Webster. Diamond Bar, CA, USA). Beyond the PV from the entrance for5mm, encircling isolation of ipsilateral pulmonary veins was performed, the ten-electrode bipolar-type circle catheter (Lasso, Biosense-Webster) was placed at each ostia of the PVs. By temperature control mode, the ablation catheter was applied with the power of30-35W and around43℃; The speed of cold saline irrigation was17-20ml/min.After treatment and follow-upAll patients should take anticoagulant therapy for three months, and metoprolol could be taken to control heart rhythm as needed, excluding relative contraindications. All of them were informed to avoid the predispositions of tachycardia such as fatigue, emotional experience, overeating, etc.The follow-up of each group was performed in two years, the first three months after the operation with taking amiodarone was defined as a blanking period, the first time of AF attack post operation was important to record, especially after the blanking period. A Holter ECG was required conveniently or the occurrence of any uncomfortable symptoms in the heart was reported faithfully. The endpoint was any type of AF was documented by ECG or24-Holter.Statistical analysisAll analyses were performed with the statistical software SPSS16.0. All continuous data were expressed as mean±standard deviation (SD), the same to frequencies and percentages for categorical variables. One-way analysis of variance (ANOVA) was used for the analysis of continuous variables between the group with PVPs disappeared and the group with any PVP delayed more than30ms. A P<0.05was considered statistically significant. The Kaplan Meier method was used for survival analysis, and the difference of recurrence between three groups was evaluated by Log-rank method.ResultsBaseline informationThirty-five (25.55%) patients had structural heart disease including28(20.44%) coronary heart disease,1(0.73%) congenital heart disease,3(2.19%) valvular heart disease,3(2.19%) sick sinus syndrome. The high metabolic diseases such as hypertension, diabetes and hyperlipidemia existed in57(41.61%),19(13.87%) and53(38.69%) patients separately. Thereinto,9(6.57%) patients concurrently suffered from paroxysmal supraventricular tachycardia which had been cured in the same operation.Complications in the operationDuring the procedure, two patients had to suspend the ablation for the sudden occurrence of cardiac tamponade, and one patient occurred pneumothorax.Recurrence and non-recurrence among paroxysmal AF patientsAmong all137patients,113ones suffered from paroxysmal AF, and the attack frequency, lasting time and syndromes varied with each individual. The operation time, each echocardiography results (LA diameter, LV end-diastolic dimension, LV ejection fraction), structural heart diseases and high metabolic diseases data were tested by t-test. It showed no statistically significant between them (P>0.05). Survival analysisAs the above,92PAF patients were divided into two groups:the group with PVPs disappeared and the group with any PVP delayed more than30ms. The recurrence situation in each group was followed up during continuous two years from the very day of radiofrequency ablation. Based on the every dictation of the start time with feeling obvious syndrome or ECG evidence conditionally, the recurrence time was roughly recorded as at least several days post-operation. By applying the Kaplan-Meier survival analysis and Log-Rank test, the result indicated that the rate of recurrence had no statistically significant difference between them in two years (P=0.140). Next, the recurrence rate separately in three months, six months and one year were tested by the same analysis method, and it showed no statistically significance (P=0.222,0.794,0.959separately).ConclusionCompared with PVPs disappeared, bidirectional block had no obvious effect on the living quality and recurrence of paroxysmal atrial fibrillation patients. |
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