The Dynamic Change Of Left Atrial Conduction Velocity With The Bipolar Electrogram Amplitude In Patients With Atrial Fibrillation

Objective:This study was meant to determine the relationship between left atrial bipolar potential amplitude and CV,whether triggers or arrhythmogenic substrate exist outside the low-voltage regions.Methods: Forty patients were involved in AF catheter ablation.Activation and voltage mapping were conducted during the procedure by pacing at the distal of the coronary vein sinus(pacing cycle length=550~650ms).Then the sochronal map and voltage map were constructed.Each LA was artificially divided into six structural regions and four voltage regions according to different regions and voltages.The CV of each regions was calculated respectively by calculating the specific value of the distance between two points along the direction of activation propagation to the difference of local activation time.The average CV of each voltage region and the mean value of the corresponding LA voltage were calculated respectively.Results: Within 40 patients,only 29 patients were included in the final analysis because the others have not meet the standard for calculating CV.A total of 2783 pairs of points were involved in CV calculation,the mean CV was(0.71±0.22)m/s(CV ranged from0.13 to 1.43m/s).CV of each structural regions(roof?anterior wall?posterior wall?inferior wall?spetal?mitral isthmus)were(0.75±0.23)m/s?(0.74±0.25)m/s?(0.66±0.21)m/s?(0.74±0.22)m/s?(0.68±0.21)m/s?(0.71±0.21)m/s.CV of each structural regions was not completely the same in different structural regions(P <0.05).CV in different voltage regions(<0.5m V?0.5~1.0m V?1.0~1.5m V?>1.5m V)were(0.44±0.14)m/s?(0.58±0.15)m/s?(0.82±0.17)m/s?(0.92±0.19)m/s respectively.CV in different voltage regions were different from each other(P < 0.05). CV can be divided into three stages with the increase of LA voltage.When the voltage was less than 0.8m V,the LA CV increased by 0.28 m/s for every 1.0m V increase of voltage(P < 0.05).When the voltage between 0.8~1.3m V,the CV increased by 0.53m/s for every 1.0m V increase of voltage(P < 0.05).When the voltage was >1.3m Vthe,CV increased by 0.05m/s(P < 0.05)for every 1.0m V increase of LA voltage.Conclusion:(1)left atrial CV presents a difference related to atrial regins,the septum and posterior wall showed slower CV.The areas with slower CV is similar to LVA.(2)The CV in different voltage regions was significantly different.The average CV increase faster at the begining then decelerate along with the the voltage variation.(3)The CV of LA shows more rapid growth at the beginning and slower growth later along with the increase of LA voltage,which can be roughly divided into three sections.The turning point was located where the LA voltage equal to 0.8m V and 1.3m VThere.may be triggers or arrhythmogenic substrate exist in the slow conduction areas outside the low-voltage zone where can be the novel targets for AF ablation.