Analysis Of Influence Factors Of The X-ray Guidance For The Right Ventricular Outlfow Tract Sepal Pacing

Objective: Long-term right ventricular apex pacing may lead to decreased thefunction of left ventricular, increased the incidence of atrial fibrillation and therisk of death. The main reason that may be delayed left ventricular activation, longQRS interval, and dyssynchronous RV-LV activation. Compared with rightventricular apex(RVA) pacing, right ventricular sepal pacing may be morephysiological. Because the sepal is on the normal physiological activationsequence point of heart, so the pacing can accurately transfer the activation tobundle branch first, and then to the Kemp wild fibers, which makes the heart workat the normal physiological activation sequence. These can improve cardiacfunction greatly and get more narrow interval of QRS. Owing to the complicatedstructure of the right ventricular outflow tract(RVOT), electrode implantation sitesexist variability. Now pacemaker implantation mostly be conducted under theguidance of X-ray. By the two-dimensional echocardiography on chest as a goldstandard to evaluate the accuracy of sites which X-ray guidance electrodeimplantation, and to analyse the influence factors. To sum up the characteristics ofthe ECG of right ventricular outflow tract and free wall pacing, which in order tobetter guide the right ventricular outflow tract spetal pacing.Methods: There were102patients (62males and40females) with dual chamberpacemaker in General Hospital of PLA from Januray2010to October2012, agefrom54to78, average age45.5+22.27. Preoperative observation of ECG, index ofechocardiography (electrocardiogram, TZI, left ventricular lateral diameter, rightventricular lateral diameter, left-right ventricular lateral diameter ratio), X-raystandad posture into spiral electrode in RVOT. Observe the position of electrodetip by echocardiogaphy after operation and the characterisitics of ECG of ventricular pacing after operation.Results: There were62patients accounted for60.78%(41males and21females)after operation electrocardiogram on the position of electrode tip located on sepal;the last were on free wall. According to the results of echocardiography, patientswere divided into sepal groups and free wall groups. There were significantdifferences in electrocardiogram TZI between the two groups: the differences inleft ventricular lateral diameter (p=0.03). There was no signaificant difference inright ventricular lateral diameter (p=0.29) and in left-right ventricular lateraldiameter ratio (p=0.65). QRS main waves’ directions of avF lead of sepal groups,free wall groups Ⅱ and free wall groups Ⅲ are all upward after operationventricular pacing ECG. The QRS shape of sepal groups’ avL lead was mainly QStype, accounted for74.2%of all sepal pacing; howerer, the QRS shape of freewall groups Ⅰ’ avL lead was R type and Rs type, accounted for72.5%of freewall pacing.Conclusions: Affected by many factors such as patients’s rotation of heart, size ofleft ventricular, the accuracy of process of the X-ray guidance for the rightventricular outflow tract sepal pacing was not high,which need other auxiliarymeans as UCG and ECG. UCG could clearly in different interface and differentangles observe the position of electrode and relationshio between electrode and allanatomic landmarks. And it was easy to operate and to applicate. After operationventricular pacing ECG had distinct characteristics in different pacing position,which could be auxiliary mean to help to locate the electrode in the process ofimplantation.