OBJECTIVES: Accurate differential diagnosis of paroxysmal supraventricular tachycardia (PSVT) has become more important after introduction of curative catheter ablation technique into clinical practice. It has been reported that ST-T changes during supraventricular tachycardia are frequent, but its association is different according to the type of PSVT and the location of the AV bypass tracts. Therefore, this study was performed to evaluate the significance of ST-T changes in addition to classic ECG parameters in differentiating AV nodal reentrant tachycardia (AVNRT) and AV reentrant tachycardia (AVRT), and predicting the location of the AV bypass tracts. METHODS: One hundred thirty patients presenting with narrow-QRS complex (<120 msec) regular tachycardia in whom the mechanism of the tachycardia was later confirmed as AVNRT or AVRT by electrophysiologic study (EPS) with successful catheter ablation were included in this study. Tachycardia cycle length, visible P wave, pseudo r' wave in V1, pseudo s wave in the inferior leads, QRS alternation, ST segments depression, and T wave inversion were evaluated in the ECGs recorded during spontaneous episodes of the PSVT and compared between patients with AVNRT (n=54) and AVRT (n=76). RESULTS: Tachycardia cycle lengths were not different between AVNRT and AVRT (355.8 +/- 50.6 msec vs. 341.9 +/- 51.4 msec). P wave during the tachycardia was significantly more frequently seen in AVRT than AVNRT, (72.4% vs. 9.3%, p<0.0001). However, pseudo r' wave and pseudo s wave were significantly more frequent in AVNRT than AVRT (59.3% vs. 7.9%, 33.3% vs. 1.3%, respectively, p<0.0001). QRS alternation was significantly more frequent in AVRT than AVNRT (34.2% vs. 11.1%, p<0.05). ST segment depression > or =1 mm was observed in 27.8% of AVNRT and 79.9% of AVRT (p<0.001). T wave inversion was more frequent in AVRT than AVNRT (30.3% vs. 7.4%, p<0.01). ST depression > or =2 mm was observed in 76.9% of the left posterior pathways, 28.1% of the left anterolateral pathways, 66.7% of the right posterior pathways, and 1.1% of the right anterior pathways. Sensitivity, specificity, and positive predictive value in differentiating AVRT from AVNRT with visible p wave were 72%, 91%, and 92%, respectively : 78%, 72%, and 80%, respectively with ST segment depression > or =1 mm, and 30%, 93%, and 85%, respectively with T wave inversion. In differentiating AVNRT from AVRT, Sensitivity, Specificity, and positive predictive value of pseudo r' wave and pseudo s wave were 59%, 92%, 84%, respectively and 33%, 99%, 94%, respectively. Sensitivity, specificity, and positive predictive value in distinguishing posterior location from anterior location of the pathways were 74%, 76%, and 72%, respectively with ST segment depression (> or =2 mm) and 46%, 83%, and 70%, respectively with T wave inversion. CONCULSIONS: ST Segment depression during PSVT can be used complementally to the classic ECG parameters in the differential diagnosis of PSVT and predicting the location of the AV bypass tracts.
Catheter Ablation ; Complement System Proteins ; Depression ; Diagnosis, Differential* ; Electrocardiography* ; Humans ; Sensitivity and Specificity ; Tachycardia ; Tachycardia, Atrioventricular Nodal Reentry ; Tachycardia, Supraventricular*