Differential Diagnosis of Slow/Slow Atrioventricular Nodal Reentrant Tachycardia from Atrioventricular Reentrant Tachycardia Using Concealed Posteroseptal Accessory Pathway by 12-Lead Electrocardiography.

OH, S., et al.: Differential Diagnosis of Slow/Slow Atrioventricular Nodal Reentrant Tachycardia from Atrioventricular Reentrant Tachycardia Using Concealed Posteroseptal Accessory Pathway by 12-Lead Electrocardiography. Slow pathways are used as both antegrade and retrograde conduction pathway in slow/slow atrioventricular nodal reentrant tachycardia (SS-AVNRT), and patients with SS-AVNRT have tachycardia ECGs mimicking atrioventricular reentrant tachycardia using concealed posteroseptal accessory pathway (PS-AVRT). Therefore, SS-AVNRT can be misdiagnosed as PS-AVRT, and the differential diagnosis is clinically important. Standard 12-lead ECGs during tachycardia were analyzed in patients with SS-AVNRT (n = 10) and PS-AVRT (n = 10). All these patients were diagnosed by electrophysiological study and underwent successful catheter ablation. Differences of the RP' intervals (dRP') between V1 and the inferior leads were evaluated. SS-AVNRT had significantly longer RP' intervals measured in V1 (167 ± 25.2 vs 137 ± 26.8 ms, SS-AVNRT vs PS-AVRT, respectively, P = 0.02), longer dRP' between V1 and II (dRP'[V1-II], 37 ± 14 vs 17 ± 6.7 ms, P = 0.0007), longer dRP'[V1-III] (39 ± 14 vs 17 ± 9.9 ms, P = 0.0011), and longer dRP'[V1-aVF] (39 ± 13 vs 20 ± 9.5 ms, P = 0.0008). The following criteria were suggested for differential diagnosis of SS-AVNRT from PS-AVRT: dRP'[V1-II] >25 ms (sensitivity and specificity: 80% and 100%, respectively), dRP'[V1-III] >23 ms (90% and 90%), dRP'[V1-aVF] >30 ms (90% and 90%). Differences of the RP' intervals between V1 and the inferior leads in the tachycardia ECGs were useful for differential diagnosis of SS-AVNRT from PS-AVRT. (PACE 2003; 26:2296–2300) [ABSTRACT FROM AUTHOR]