Prediction Of The Outcome Of Radiofrequency Catheter Ablation For Paroxysmal Atrial Fibrillation By The Signal-averaged P-wave Duration

Objective: Radiofrequency catheter ablation (RFCA) is widely accepted as aneffective treatment for the paroxysmal atrial fibrillation (PAF), the main procedure ispulmonary veins isolation (PVI). But there are many questions over the efficacy ofRFCA with higher recurrence rates and over the frequent requirement for repeatprocedures. We used the signal-averaged electrocardiogram (SAECG) to study theinfluence of RFCA on P-wave duration (PWD) and studied whether P-wave duration isassociated with successful outcome after initial PVI.Methods: From November2011to July2012, fifty-three consecutive patientsunderwent first RFCA in our hospital for paroxysmal atrial fibrillation (AF). Thepatients were evaluated to determine their clinical history and then underwent physicalexamination and transthoracic and trans-esophageal echocardiography (TEE) to excludethrombosis in left atrial. The patients also underwent pulmonary veins CT to clearpulmonary veins’ anatomy relationship and diameter. Heparin was used after atrialseptal puncture. The radiofrequency ablation was performed guiding by Carto3system.The individually ablation strategy is circumferential pulmonary vein isolation, theendpoint of the procedure was complete bidirectional conduction block between thePVs and LA, and the Lasso was used to confirmed it. Cardioversion would beperformed to restore sinus rhythm if AF was not terminated after the procedures weredone. The patients were treated with the anticoagulant warfarin for at least4weeks witha targeted international normalized ratio (INR) of2.0–3.0. For each patient, an ECG recording was taken by the CardioSoft Software Program at the start and end of theablation procedure. The patients were divided into two groups: Successful Group andRecurrence Group according to whether the atrial fibrillation recurrence during the atleast6months’ post-procedure follow-up. Statistics analysis was performed with SPSS17.0to compare the PWD between the two groups and the changes after the PVI foreach patient.Results: Average PWD decreased from141.1±13.5ms to139.4±15.2ms，(P=0.058) after the PVI，but there were no significant statistically differences betweenthem. PWD before（137.0±9.5ms vs153.9±16,2ms，P<0.01）or after the procedure（135.6±10.8ms vs151.1±20.7ms，P<0.01）was significantly shorter in successfulgroup. The Logistic regression analysis revealed that the prolonged P-wave duration inpatients with paroxysmal atrial fibrillation is the independent predictor of recurrence.PWD before PVI=151.1ms have69.2%sensitivity and90.5%specificity and thepositive predictive value is75%.Conclusion：The prolonged P-wave duration in patients with paroxysmal atrialfibrillation is the independent predictor of recurrence. PWD is significantly longer incases of recurrence outcome after PVI, but PVI results in a poor shortening in PWD.