The Relationship Between Electrocardiogram P Wave Parameters And Recurrence After Radio Frequency Catheter Ablation In Paroxysmal Atrial Fibrillation Patients

Objective: Radiofrequency catheter ablation(RFCA) is the first-line therapeutic method for symptomatic drugrefractory paroxysmal atrial fibrillation(PAF) patients, the main ablation procedure is circumferential pulmonary vein isolation(CPVI). However, patients are suffered with high rate of recurrence of AF after ablation procedure no matter which ablation strategy. There are many factors can predict AF recurrence after ablation in clinical. Our research mainly measured the P wave parameters in surface electrocardiogram(ECG), and compared their changes before and after RFCA, to explore the predictive value of P wave parameters and their changes about AF recurrence within 1 year after RFCA.Methods: The study enrolled 130 consecutive symptomatic drugrefractory PAF patients who underwent first RFCA in our department from August 2009 to April 2014. Their clinical history, laboratory examinations and thoracic echocardiography indexes were recorded, and then underwent trans-esophageal echocardiography(TEE) to exclude thrombosis in left atrial or left atrial appendage.For every patient, a 12-lead ECG examination were operated before and after RFCA procedure during sinus rhythm, and then measured the P wave duration(PWD), P wave amplitude(PWA) of 12 leads in the same beat and P wave terminal force(Ptf) in lead V1, calculated P wave dispersion(Pd) and P wave index(P-index) according the 12 leads PWD, and counted the inetratrial block(IAB) and P wave notch(PWN) numbers. And we selected the results of leadⅡto analysis PWD and PWA.The changes of PWD、PWA、Ptf、Pd、P-index、PWN proportion and lead numbers and IAB after RFCA were compared respectively. Every patients was followed up within 1 year after RFCA, and analysis the relationship between P wave parameters and AF recurrence. Left atrial diameter(LAD) more than 38.6 mm is defined as LA enlargement, and analysis the relationship between P wave parameters and AF recurrence in different LAD subgroup. the predictive value of P wave parameters about AF recurrence was analyzed by ROC curve, and whether P wave parameters were clinicprognostic factors of AF recurrence were investigated by Kaplan-Meier analysis of survival curves and multivariate logistic regression analysis.Results: 1. During a mean follow-up of 10.2±2.7 months, 44 patients had AF recurrence, the recurrence rate for all patients after RFCA within 1 year was 33.8%;2. Compared with patients in non-recurrence group, patients in recurrence group had larger LAD, CHADS2 and CHA2DS2- VASc score(P< 0.01 or 0.05);3. Patients in recurrence group had greater PWD, Pd, P-index and larger a IAB proportion than those of patients in non-recurrence group before RFCA(P< 0.05 or 0.01), and patients in recurrence group had greater PWD and the absolute of Ptf, larger IAB and PWN proportion, more PWN lead numbers than those of patients in non-recurrence group after RFCA(P< 0.05 or 0.01);4. The PWD, PWA, absolute of Ptf, p IAB and a IAB proportion, PWN proportion and lead numbers were decreased(P< 0.05 or 0.01), and heart rate was increased than baseline(P< 0.001) in all patients. Further, the smaller reduction of PWD was correlated with AF recurrence(P= 0.002);5. Pearson correlation analysis showed that LAD were positive correlated with Pd(r=0.182, P=0.038), P-index(r=0.182, P=0.038) and the absolute of Ptf(r=0.357,P<0.001). In normal LAD group, patients in recurrence group had greater Pd and P-index than those of patients without recurrence(P<0.05); In LAD enlargement group, there were no statistical difference of PWD, Pd, P-index of patients between recurrence and non-recurrence groups(P>0.05);6. Multivariate logistic regression analysis showed that LAD(HR=1.099,95%CI: 1.001~1.207, P=0.046), △PWD(HR=0.943,95%CI: 0.904~0.984, P=0.006), Pd(HR=1.098,95%CI: 1.024~1.176, P=0.008) and a IAB(HR=5.426,95%CI: 1.706~17.259,P=0.004)are independent predictive factors of AF recurrence after RFCA within 1 year in PAF patients;7. ROC curve shows the predictive value of P wave parameters about AF recurrence after RFCA are moderate, the largest area under the curve(AUC)is Pd before RFCA, which is 0.705, the optimal cut-off point is 37 ms with a sensitivity of 56.8% andspecificity of 80.2%, and the successful rate between Pd more than 37 ms and less than 37 ms had remarkable statistical difference(45.0% vs. 75.6%, P = 0.001).And the optimal cutoff point value for PWD before RFCA is 133 ms with a sensitivity of 47.7% and specificity of 79.1%, and the successful rate between PWD more than 133 ms and less than 133 ms had remarkable statistical difference(47.2% vs. 73.4%, P=0.001);8. Kapla-Meier survival analysis shows that the rate of freedom of AF recurrence among patients with PWD≥133ms is significantly lower than patients with PWD<133 ms(Log-rank=9.630,P=0.002).Similar results were also seen patients with Pd≥37 ms and Pd<37ms(Log-rank=10.054,P=0.001), and with a IAB and without a IAB(Log-rank=27.970,P<0.001).Conclusions: 1.The PWD, PWA, absolute of Ptf, p IAB and a IAB proportion, PWN leads were reduced and heart rate was increased after RFCA, and the PWD reduction was closely associated with AF recurrence within 1 year after RFCA in PAF patients;2. LAD, CHADS2 and CHA2DS2-VASc score,and some P wave parameters both before and after RFCA were closely associated with AF recurrence within 1 year after RFCA in PAF patients;3. Atrial electrical remodeling may prior to structure remodeling in PAF patients, and even left atrial diameter is normal or slightly enlargement, Pd、P-index are also closely associated with AF recurrence within 1 year after RFCA in PAF patients;4. The predictive value of P wave parameters about AF recurrence after RFCA are moderate, the biggest is Pd before RFCA.On the basis of critical line of Pd 37 ms and PWD 133 ms could well predict AF recurrence within 1 year after RFCA;5. LAD,△PWD, Pd and a IAB are independent predictive factors of AF recurrence within 1 year after RFCA in PAF patients.