Comparison Of Four Electrocardiographic Algorithms Of Location Diagnosis For Outflow Tract Ventricular Arrhythmias

(Background]Ventricular arrhythmia, including ventricular premature beat and ventricular tachycardia, is an arrhythmia which is Originated in Ventricular and whose electrocardiograms show wide QRS complex..There are two kinds of ventricular arrhythmia including Pathology and idiopathic,depending on who is with organic heart disease or not. The catheter radiofrequency ablation has become an important means for the treatment of ventricular arrhythmia.Being dirrerent from ventricular arrhythmia due to organic heart disease, The success rate of definite diagnosis of idiopathic ventricular arrhythmias of catheter radiofrequency ablation is higher.,which is up to 85%-95%. Idiopathic ventricular arrhythmias in theory can be originated from any part of the ventricle,who is common at outflow tract and has a higher safety and the success rate.The electrocardiogram of outflow tract ventricular arrhythmia shows The main wave upward of Ⅱ Ⅲ avF and high amplitude of R wave. According to the QRS wave of chest lead QRS wave form, usually the form of right bundle branch block most originated in the left, with the high opportunity of the left side of the ablation. Insteadthe left bundle branch block form most originated in the right with the high chance of success at right side ablation. In outflow tract of left ventricular arrhythmias, ablation of supravalvular aortic is more common than the subarotic. The right ventricular outflow tract is Conic shape,which goes through the left upper sider of aortic sinus cusps,who borders on the septum of the right ventricular outflow tract and whose Left and right coronary sinus isin front of the septum of the right ventricular outflow. In the outflow tract ventricular arrhythmias, generally ventricular arrhythmias originated from right ventricular outflow tract has their body surface electrocardiogram chest lead characterized by left bundle branch block, ventricular arrhythmias originated in the left ventricular outflow tract has its body surface electrocardiogram of chest lead right bundle branch block, AS the right ventricular outflow tract and the aortic sinus of the left ventricular outflow tract close to anatomical position, the ventricular arrhythmia originated from the two parts have very similar body surface ecg expression sometimes,which are characterized by left bundle branch block.and the main wave upward of QRS complex on II III avF, the identification is difficult. At this time the chest lead QRS wave forms can not accurately reflect the origin from the left or the right. Due to different origin of outflow tract ventricular arrhythmias, its operation method is not the same. Uaually, if the electrocardiogram (ecg) shows the outflow tract origin,the clinicist often map on right ventricular outflow tract first,.If the right cannot obtain the ideal target, they need artery puncture and try again. Then can cause the repeated puncture at different positions of the patients, extend the X-ray exposure time and operation process, which increases the risk of surgical complications and improve the patient’s relevant expenses. The interpretation of electrocardiogram, therefore, not only help determine origin of ventricular arrhythmia, but also help in operation to determine the ablation target, which can reduce the repeat vascular puncture, the radiation exposure time and operation process, the risk of surgical complications, and the cost of surgery for the patient. Thereforce preoperative judgement of the origin of ventricular arrhythmia through electrocardiogram has important clinical significance and value.Judgment method of electrocardiogram of ventricular arrhythmia origin, especially for right ventricular outflow tract and aortic sinus, the two adjacent anatomic site,was first put forward by Ouyang F et al, who put forward R/S-wave amplitude indices. This method contains V1 and V2 lead time limit of R wave and the ratio of the QRS duration the ventricular premature beat (ventricular tachycardia) as index, R wave time of lead VI and V2 R wave amplitude and S wave amplitude ratio as the R wave amplitude index, if the R wave index is more than 30%and R wave amplitude index is more than 50% which indicates origin in ASC, otherwise it originated in RVOT conversely.In 2011, Yoshida, N et al scholars proposed a new index, the transitional zone index. The method defines the R wave and S wave ratio of 0.9-1.1 of the chest lead as transition zone lead.If a transition zone interface between two lead, the transitional zone is the previous number of transition area integral plus 0.5, the sinus rhythm lead number of the transition zone is the transition zone index of sinus rhythm,while the ventricular arrhythmia lead number of the transition zone is the transition zone index of ventricular arrhythmia. The transitional zone index comes from the transition zone index of ventricular arrhythmia minus the sinus rhythm of the transition zone.If the transition zone index< 0, it indicates the origin in ASC.If the transition zone index> 0, it shows the origine in RVOT.That same year, Betensky, b. P et al also puts forward V2 transition ratio as an index identificating ROVT with ASC of the origin of ventricular arrhythmia.It uses V2 lead R and Swave amplitude of ventricular arrhythmia and sinus rhythm. Its calculation formula isV2 transition ratio=(R/R+S)OTVA/(R/R+S)SRStudy found that ventricular arrhythmias originated from the left ventricular outflow tract has a higher V2 transition ratio than that orginated from the right ventricular outflow tract.The judgment standard is V2 transition ratio> 0.5, indicated the origine in ASC within; while V2 transition ratio< 0.5, indicated the origine in RVOT, whose accuracy is 91%.As electrocardiogram is being paid more and more attention, Recently Yoshida, N et al proposed Sv2/Rv3 index as a new judge index.it uses S wave amplitude of V2and R wave amplitude of V3 ratio in ventricular arrhythmias as the judgment standard, Sv2/Rv3 index which is less than 1.5 tips originated in ASC, if it is more than 1.5,it tips originated in RVOT; Yoshida,N observed 207 cases of outflow tract ventricular arrhythmias who successfully went through catheter radiofrequency ablation.The cardiac arrhythmias contain the 154 cases of patients with right ventricular outflow tract, and 53 patients with left ventricular outflow tract,.The sensitivity of Sv2/Rv3 index is 89%,and the specificity is 94%, which has a good clinical value.The above four methods have different characteristics, but there is no comparison on advantages and disadvantages among them, and the systemically comparison is lack,which makes the choice of electrocardiogram method of outflow tract ventricular arrhythmias confuse,and there is no unified conclusion.We collected patients with premature ventricular beat or ventricular tachycardia in NanFang hospital, southern medical university who have gone througu radiofrequency ablation surgery successfully according to their electrocardiogram and operation records. The successful ablation area in the operation is seen as the goldden standard,According to the index of four types of electrocardiogram methods, and the baseline smooth, clear graphics of the cardiac cycle in sinus rhythm and ventricular arrhythmias, we measure index and calculate,the judgment results of each method, and compare with the result of the gold standard for every patient one by one. By comparing four methods systemically.We want to compare the quality between different methods, and the complex degree, in order to provide the reference value of methodological choice of outflow tract ventricular arrhythmias patients undergoing atheter ablation in the b future.[Object and Methods 1We collect medical records, and extract the patient medical record data, the results of electrocardiogram, discharge diagnosis of patients in department of cardiovascular internal medicine (including CCU ward) in NanFang,, hospital, southern medical university on January 1,2010 to December 31,2013, who went througj successful radiofrequency ablation surgery of ventricular arrhythmia (including ventricular premature and ventricular tachycardia) patients,and analyze the operation records and other relevant information.Inclusion criteria for this research contain:1) patients with radiofrequency ablation surgery successfully, and operation record shows targets in the outflow; 2) patients with ventricular premature beat has 24 hours dynamic electrocardiogram examination, and results showing that 10% or greater uniform premature ventricular load or more than 10000/24 hours.3) patients with standard 12-lead electrocardiogram data of sinus rhythm and ventricular arrhythmia which is characterized by left bundle branch block shape, QRS upward of Ⅱ, Ⅲ, avF waves; 4) patients with anti-arrhythmic drugs withdraw at least five half-life who preoperative ever take anti-arrhythmic drugs; 5) no abnormalit of cardiac physical examination, echocardiography and X-ray chest radiography.Exclusion criteria of this research include:1) echocardiography showing a heart atrioventricular enlargement, hypertrophy and other physical changes; 2) coronary atherosclerosis heart disease found by coronary angiography or coronary CT angiography 3) patients with success, ablation in other areas except the outflow tract.The success criteria of radiofrequency ablation of ventricular arrhythmia are defined as disappearance of ventricular tachycardia or ventricular permature beat after radiofrequency ablation in patients or appearance of accidental ventricular premature beat (1/min or less), or the number of ventricular premature beat< 10 similar to preoperative after drops of isopropylepinephrine (ISO) observing 30 minutes.According to the ablation target, patients were divided into right ventricular outflow tract (RVOT) and aortic sinus (ASC) groups.Patient with different method obtained different judgments,according to each approach steps. The judgments of the each method are compared with the the gold standard, surgery successful ablation target. The sensitivity, specificity, positive predictive value, negative predictive value of each method are get and the ROC curves are drawn..[Results](1) After screening the patients of the department of cardiovascular internal medicine (including CCU ward) in Nanfang hospital, southern medical university on January 1,2010 to December 31,2013,and omiting the duplication in hospital patients according to the inclusion criteria and exclusion criteria,202 cases of patients are collected. There are 94 men,108 women. Age ranges from 40.3±15.2 in ROVT group and 42.6±16.6 in the ASC group, In the 202 patients, there are 144 cases whose ablation target is located in right ventricular outflow tract, with intervals of 124 cases,20 free wall; There are 58 cases targets in of aortic sinus,.51 cases is located in the left coronary sinus, right coronary sinus in 3,4 cases between left and right coronary sinus. There are 42 patients with transposition of the heart, judged by the chest lead of electrocardiogram,31 cases of the RVOT group,11 cases of ASC group. Each clinical characteristics index of patients in two groups including gender, age, preoperative ventricular premature beat of 24 hour number, preoperative ventricular premature beat load and left ventricular ejection fraction, the existence of heart transfer in sinus rhythm, ventricular premature beat number 24 hours after radiofrequency ablation have no statistical difference (P> 0.05).(2) Indicators in addition to the four indicators has no statistically significant difference of the two groups (P> 0.05), the rest of the indicators between the two groups were statistically significant (P< 0.05).(3) Despite the transposition og heart in sinus rhythm, overall analysis was carried out on the patients, four ways can be concluded that the overall patients, in the comparison of the sensitivity of the V2 transposition index> Sv2/Rv3 index> R wave duration and amplitude index> transition zone index (V2 migration.index up to 93.5%, followed by Sv2/Rv3 index 89.2%, R wave duration and amplitude index was 80.5%, the transition zone index, lowest of 62.3%). Specifity Sv2/Rv3 index> R wave duration and amplitude index> transitional zone> V2 migration index (Sv2/ Rv3 index up to 93.8%. The second is the R wave duration and amplitude index 92.1%, transitional zone index was 91.3%, the iowest for V2 migration index. Positive predictive value is Sv2/Rv3 index> R wave duration and amplitude index> V2 migration index> transition zone index (Sv2/Rv3 index up to 85.3%, followed by R wave duration and amplitude index 81.7%, V2 migration index by 76.7%, the lowest for transition zone index (78.5%); Negative predictive value is V2 migration index> Sv2/RV3 index> R wave duration and amplitude index> transition zone index (V2 migration index up to 95.2%,88.1%, followed by Sv2/Rv3 index R wave duration and amplitude index by 83.6%, the lowest for transition zone index (81.2%). Four methods area under the ROC curve, transition zone index 0.943, V2 migration index 0.903 R wave duration and amplitude index 0.877. P values of comparing the Four methods were less than 0.1, four methods,which shows that there was no statistically significant difference of the area under the ROC curve.[Conclusion](1) Dispute the presence of heart transfer in the sinus rhythm, overall analysis was carried out on the patient, which can be concluded that in the overall patients, V2 migration index has the highest sensitivity, whlie highest specificity for Sv2/Rv3 index, positive predictive value for Sv2/Rv3 index, negative predictive value for Sv2/Rv3 index. As to the area under the ROC curve of four methods, the smallest is the transition zone index, difference is statistically significant compared with the rest of the way.And the rest of the three methods were found no statistically significant difference. Alone to In consideration of patients with heart inversion in sinus rhythm, the highest sensitivity is V2 migration index, the highest specificity is Sv2/Rv3 index, positive predictive value is Sv2/Rv3 index, negative predictive value is V2 migration index. There was no statistically significant difference for the area under the ROC curve.(2) Dispute the heart transposition, Sv2/Rv3 index and V2 migration index, and R Wave duration and amplitude index have the same the diagnostic value.The diagnostic value of transition zone index is less than the others under the condition of no heart transfer, while when heart transposition is present value remains the same. AS the Sv2/Rv3 index needs only measure the index of ventricular arrhythmia onset, and the measurement and calculation method of electrocardiogram data are easier than others. When there is no heart transposition,the diagnosis value of Sv2/Rv3 index is higher than the transition zone index, In conclusion,no matter the heart have transposition,Sv2/Rv3 index can be used as the preferred electrocardiogram judgment method of outflow tract ventricular arrhythmias. The other methods have very good supplementary function.