ST Segment Depression and T-wave Inversion during Superaventricular Tachycardia

Abstract

Background：Paroxysmal supraventricular tachycardia(PSVT is frequently associated with ST segment depression or T-wave inversion. However, the mechanism of ST-T changes in the context of various mechanisms of PSVT is not clear. The purpose of this study was to evaluate the prevalence of ST depression or T-wave inversion during PSVT and determine whether these changes are related to the mechanism of PSVT or the rate of the tachycardia. Method：Twelve-lead electrocardiograms were recorded during sinus rhythm and during PSVT in 163 patients who underwent an electrophysiologic study for ablation. Tachycardia cycle length, presence of ST depression or T-wave inversion during PSVT and the mechanism of tachycardia were evaluated. Significant ST depression was defined as at least 1mm horizontal or downsloping depression, measured 80ms after the J point and T-wave inversion as inversion of T-wave which was positive in the same lead during sinus rhythm. Results：1 The mechanism of PSVT analysed for ST segment depression was atrioven-tricular nodal reentry tachycardia in 60 cases and atrioventricular reentry tachycardia in 111 cases. The mean tachycardia cycle length was 373.8±68.0 msec. 2 ST depression and T-wave inversion was observed during PSVT in 56%(96/171 and 45%(77/171 of cases, respectively. 3 Tachycardia cycle length, degree of ST depression and number of leads with ST depressison are not different according to the mechanism of PSVT. 4 ST depression and tachycardia cycle length had significant correlation, especially in atrioventricular reentry tachycardia. 5 Leads with T-wave inversion during tachycardia was observed more frequently in atrioventricular reentry tachycardia than atrioventricular nodal reentry tachycardia(p<0.05, but no difference between manifest and concealed bypass tract. Conclusion：ST segment depression is rate-related phenomenon and not different according to