Evaluation Of Predictors Of Atrial Fibrillation Recurrence In Paroxysmal Atrial Fibrillation Patients After Cryoballoon Ablation By Echocardiography

Objective: Atrial fibrillation is one of the most common arrhythmias.Paroxysmal atrial fibrillation(PAF)is the early stage of atrial fibrillation progression.Effective treatment of PAF is of great significance to improve patients' life quality and reduce mortality.At present,the effectiveness and safety of cryoballoon catheter ablation(CBCA)in the treatment of PAF by pulmonary vein isolation has been confirmed,but there is still a certain recurrence rate of atrial fibrillation.This study aimed to evaluate the predictors of atrial fibrillation recurrence in PAF patients undergoing CBCA and to provide evidence for prognosis.Method:1.Subjects: 114 PAF patients were selected as the case group(PAF group)and 46 healthy patients with matching age and gender were selected as the control group(Con group).2.Echocardiography: Conventional echocardiography and two-dimensional speckle tracking echocardiography(2D-STE)were performed within 24 hours before CBCA to detect the atrial size,function and left atrial electromechanical conduction time.Echocardiographic parameters:Left atrial end-systolic dimension(LAD)at end-systolic stageLeft atrial maxium volume(LAVmax)at end-systolic stageLeft atrial presystolic volume(LAVp)at diastolic stage before left atrial contractionLeft atrial minimum volume(LAVmin)at end-diastolic stageLeft atrial volume index(LAVI)= LAVmax / BSALeft atrial ejection fraction(LAEF)=(LAVmax-LAVmin)/ LAVmax:reflecting left atrial reservoir functionLeft atrial passive ejection fraction(LAPEF)=(LAVmax-LAVp)/ LAVmax:reflecting left atrial conduit functionLeft atrial active ejection fraction(LAAEF)=(LAVp-LAVmin)/ LAVp:reflecting left atrial pump functionLeft atrial strain during reservoir phase(LASr): reflecting left atrial reservoir functionLeft atrial strain during conduit phase(LAScd): reflecting left atrial conduit functionLeft atrial strain during contraction phase(LASct): reflecting left atrial pump functionLeft atrial electromechanical conduction time by 2D-STE(STE-LAEMT):the time duration from P wave onset to left atrium contraction by 2D-STE,reflecting left atrial electric conduction timeThe parameters of the right atrium were measured as the same as the left atrium:Right atrial maxium volume(RAVmax)Right atrial presystolic volume(RAVp)Right atrial minimum volume(RAVmin)Right atrial ejection fraction(RAEF)=(RAVmax-RAVmin)/ RAVmaxRight atrial passive ejection fraction(RAPEF)=(RAVmax-RAVp)/ RAVmaxRight atrial active ejection fraction(RAAEF)=(RAVp-RAVmin)/ RAVpRight atrial volume index(RAVI)= RAVmax / BSARight atrial strain during reservoir phase(RASr)Right atrial strain during conduit phase(RAScd)Right atrial strain during contraction phase(RASct)3.Cryoballoon catheter ablation: Transesophageal echocardiography was performed within 2 days before ablation to exclude atrial and atrial appendage thrombosis,pulmonary vein CT was performed to determine the anatomical structure,and the second generation cryoballoon was used for pulmonary vein ablation until pulmonary vein electrical isolation was achieved.4.Follow-up: Patients were required to undergo 24 h dynamic electrocardiogram at 1,3 and 6 months after the ablation and every 6 months thereafter,and immediately undergo electrocardiogram if there were palpitations,chest tightness and other symptoms.Blank period was defined as within 3 months after ablation,during which atrial fibrillation,atrial flutter or atrial tachycardia lasting more than 30 seconds was defined as a blank period recurrence.Atrial fibrillation,atrial flutter or atrial tachycardia lasting more than 30 seconds 3 months after the ablation was defined as atrial fibrillation recurrence.Patients were divided into recurrence group and non-recurrence group.The predictors of recurrence after CBCA were determined by comparing the differences in baseline data and ultrasound parameters between the two groups.Results:1.PAF patients atrial function changes1)Left atrial function changesLAD,LAVmax,LAVp,LAVmin and LAVI were significantly inscreased in the PAF group compared with the Con group,while LAEF and LAAEF were significantly decreased(P < 0.001),LASr,LAScd and LASct were also significantly decreased(P < 0.05),suggesting that the left atrium was enlarged and the reservoir function,conduit function and pump function were decreased.STE-LAEMT of the PAF group was significantly longer than the CON group(P < 0.05),suggesting that the left atrial electrical conduction rate was decreased.LAVI was enlarged in only 43 patients(38%)in the PAF group,indicating that most patients have no significant changes in atrial size despite decreased atrial function.2)Right atrial function changesRAVmax,RAVp,RAVmin and RAVI were significantly inscreased in the PAF group compared with the Con group,while RAPEF,RASr,RAScd and RASct were significantly decreased(P < 0.05),suggesting that the right atrium was enlarged and the reservoir function,conduit function and pump function were decreased.2.Predictors of atrial fibrillation recurrence in PAF patients after CBCAPatients were followed up for 4-29 months,with an average follow-up time of 18±8 months.A total of 16 patients(16.8%)had blank period recurrence,and 30 patients(26.3%)had atrial fibrillation recurrence.Univariate analysis showed that the recurrence group had a smaller LAAEF(P < 0.05),a higher blank period recurrence rate(P < 0.05),and a longer STE-LAEMT(P < 0.05).Multivariate Cox proportional risk regression analysis showed that blank period recurrence and STE-LAEMT were independent predictors of atrial recurrence in PAF patients after CBCA.ROC analysis showed that STE-LAEMT ? 202 ms predicted atrial fibrillation recurrence with a sensitivity and specificity of 0.640 and 0.714 respectively.PAF patients were divided into two groups according to the STE-LAMET cut-off point value.Kaplan-meier survival analysis showed that the atrial fibrillation recurrence rate was higher in the STE-LAEMT ? 202 ms group(42.11%vs.14.06%,P = 0.001).Conclusion:1.In PAF patients,the left and right atria are enlarged with decreased reservoir,conduit and pump function,and the left atrial electrical conduction rate decrease.2.Blank period recurrence and STE-LAEMT were independent predictors of atrial fibrillation recurrence in PAF patients after CBCA.3.The recurrence rate after CBCA was higher in patients with STE-LAEMT ? 202 ms.