| ObjectiveThrough analysing the various characteristics of narrow QRS complex tachycardias in electrocardiograms to differentiate AV reciprocating tachycardia from AV node reentrant tachycardia and locate the accessory pathway in AV reciprocating tachycardia is thought to be helpful to guide the pharmacological therapy and has important value on preliminarily determining the process of radiofrequency catheter abation~ predicating the risk. Previous studies have evaluated the utility of 12-lead ECG for differentiating PSVT types including the mean rate of tachycardia .. converse P wave a pseudo r?deflection and a pseucdo S deflection~ QRS alternant. ST7segment depression and T wave conversion, but those studies have shown conflicting results on the usefulness of some ECG criteria.it usually focused on studing the ST segment depression T wave conversion, but have not evaluated the part of durative time of ST segment depression in differentiation of narrow QRS comp~ex tachycardia. the purpose of this study is to evaluate the value of ST segment depression and it抯 durative time in differentiating AV reciprocating tachycardia from AV node reentrant tachycardia and locating accessory pathway of narrow QRS complex tachycardia. Furthermore, ST segment depression and it抯 durative time are also used to differentiate AV reciprocating tachycardia from AV node reentrant tachycardia according to it抯 appearances in two or more leads.Methods141 patients with narrow QRS complex tachycardia were recorded their 12-lead ECGs in both sinus rhythm and paroxysmal supraventricular tachycardia. all patients received radiofrequency abation lately and were fit for the below standards.1: No branch blocks were found in ECGs of sinus rhythm, noSatrial or ventricular inflations was found in ultrasound examination.2: The time of QRS complex in tachycardias less than 0.11 s,and the atrial and ventricular conduction of tachycardias showed 1:1.3: All patients received electrophysiologic tests and got the successful radiofrequency abation.4: Noninvasive tests were used to exclude patients from ischemic ST segment changes.5: Sinus tachycardia and atrial tachycardia~. Atrial flutter~ atrial fibrillation were ruled out.6: Blood tests were used to rule out disturbances in the plasma sodium~ potasium concentrations.The 12-lead ECGs were recorded more than ten circles, all patients?ECGs were analysed for the following information.1: The cycle length.2: The magnitude of ST segment depression and the durative time of ST segment depression measured from J point to horizontal line, the of magnitude of ST segment depression was evaluated at 8Oms after the J point in downsloping ST segment depression, but it was measured at J point in upsloping ST segment depression, the9durative time of segment was got between two inner sides of J point and crucial point between ST segment and horizontal line.Criteria for locating accessory pathway: the accessory pathways of left side were located according to the distance between the coronal sinus hole to site of the accessory pathway around mitral annulus, beyond 5cm, the accessory pathways were located in AL. 3-5cm located in LL, the others were septal. for the right side, they were located in LAO projection around tricuspid annulus. the accessory pathways of 9:30-12:00 point were thought RA, 8:30-9:30 were RL, 8:30-6:00 were RP, the others were located in septa location.Statistical anaysis: the mean tachycardia cycle lengths in twogroups were showed as X 盨D, 憈?test was used to compare difference between two groups, other counting data were compared by x2 test and A 憄?value<0.05 was considered significant.ResutsAmong all patients with narrow QRS complex tachycardia, 54 patients were AVNRT, 87 patients were AVRT using concealed accessory pathway, the mean tachycardia cycle lengthes in two groups were 335+5 lms. 328+43ms(respectively). no significant10... |
