The Location Of Interatrial Conduction As Well As The Relationship Of P Wave In Patients With Paroxysmal Atrial Fibrillation

ObjectiveThis study was to identify the insertion points of Bachmann bundle(Bachmann’s Bundle, BB) which is one advantage pathway of heart room according to atrial activation mapping by building up three dimensional anatomical model of left and right atrium in CARTO3 system. The other aim was to investigate the activation time of the left, right and all atrium in the patients with paroxysmal atrial fibrillation and try to find out the relations between the atrium conduction and P wave duration(P wave Duration, PWD), PR segment and Ptf V1(P wave terminal force in V1) in the surface ECG.Methods1. 27 patients(19 males and 8 females) with paroxysmal atrial fibrillation who meet with the study criteria and agreed with the radiofrequency ablation were enrolled.2. All the patients received conventional transthoracic echocardiography(Transthoracic echocardiography TTE) and transesophageal echocardiography(Transesophageal echocardiography TEE) examination to evaluate the cardiac structure and the presence of atrial thrombus.3. Using navi-star catheter(NAVISTAR THERMOCOOL, Biosense Webster) to establish three-dimensional anatomical model of left and right atria in CARTO3 system,Electroanatomic mapping was performed using either a Circular mapping catheter(Lasso SAS), a 7F Navi-Star or Thermo Cool catheter. 10 diagnostic electrophysiological catheter was placed to the coronary sinus as a time reference. In sinus rhythm, the coronary sinus electrode as one time reference, activation time can be manually corrected when necessary. The left atrial insertion point of Bachmann bundle and Sinoatrial Node(SN)were measured Respectively; The earliest site of right atrium was right atrial insertion point of Bachmann bundle, when LAA was paced; Mapping the atrioventricular node(Atrioventricular Node, AVN)according to His potential, and taking the points from above parts, the right atrial appendage(Right Atrial Appendage, RAA) and left atrial appendage(Left Atrial Appendage, LAA) in sinus rhythm. Measuring the exciting time of each point when the coronary sinus as a reference4. According to the isochronal activation mapping, the earliest and latest activation points of the RA and LA were selected respectively and the atrial conduction time was measured.5. P wave duration, P-R section, in II lead and V1 lead terminal force Ptf V1 of the surface 12 lead ECG were measured before radiofrequency ablation.6. Analysing the relationship between the related indicators, atrial size and atrial conduction.Results1. The insertion point of Bachmann bundle in the LA and RA was located in a wide area. According to atrial mapping position in the three-dimensional anatomical model,the BB insertion point of the right atrium was the partial interval side which was on the top of the right atrium, and the BB insertion point of the left atrium was near the front right upper pulmonary vein, which were consistent with the description of the anatomical study before.2. The sequence of atrial activation is: the sinus impulse begins from the junction of vena cava and right atrium(mapping displayed insinus area) and then attracts the activation of the right atrial, which conducts to the right atrial and through atrium conduction(Bachmann bundle) stimulates the anterior wall of the left atrium. The activation is continuously conducted to the lower part of the right atrium and the front wall of the left atrium, which results in the activation of other parts of the left and right atrium ultimately.3. The right atrial activation time was 94.00 ± 14.95ms(68.00 ms ~ 125.00ms), left atrial activation time was 80.81 ± 11.317ms(56ms ~ 103ms), and all atrial activation time was 116.19 ± 20.63ms(81.00 ms ~ 152.00ms).4. The mean duration of Lead II P-wave was 122.00 ± 16.26ms(85.00 ms ~160.00ms), PR segment was 57.85 ± 20.69ms(18ms ~ 101ms) and Ptf V1 was-0.07 ±0.02 mm · s(-0.11 mm · s ~- 0.02 mm · s).Conclusions1. we can map out the left and right atrial insertion points of Bachmann bundle which was advantage channel of atrium conduction by using three-dimensional anatomical model mapping.2. The atria model reconstruction of the LA and RA can be completed by using three-dimensional electro-anatomical mapping, the whole activation processe can be observed throughout the atrium in the isochronal activation mapping.3. According to the activation mapping, The atrial conduction time in sinus rhythm can be computed in patients with atrial fibrillation.4. P wave duration was prolonged, Ptf V1 was reduced and P-R segment was shortening in patients with paroxysmal atrial fibrillation.5. Left atrium activation time was positively correlated with the P wave duration, and was negative correlation with Ptf V1.But there was no correlation between P-R segment time, left atrial size and left activation atrial time and there was no correlation between right atrial activation time and P wave duration, P-R segment time, Ptf V1 period and right atrial size.