September 1, 1995Open Access
Comparison of Atrial‐His Intervals During Tachycardia and Atrial Pacing in Patients with Long RP Tachycardia
Structured PICO
Does the difference in atrial-His (AH) interval between atrial pacing and tachycardia differentiate atypical AVNRT from other causes of long RP tachycardia?
P
Population
45 patients with long RP tachycardia (12 with atypical AV nodal reentrant tachycardia [AVNRT], 21 with orthodromic reciprocating tachycardia [ORT], and 12 with atrial tachycardia)
I
Intervention
Measurement of atrial-His (AH) interval during high right atrial pacing at the tachycardia cycle length in the setting of sinus rhythm
C
Comparator
Measurement of AH interval at the His-bundle position during the tachycardia
O
Outcome
Difference in AH interval between atrial pacing and tachycardiasurrogate
Comparing the AH interval during atrial pacing versus during tachycardia provides a simple and rapid diagnostic maneuver to differentiate atypical AVNRT from other long RP tachycardias.
Abstract
INTRODUCTION: The purpose of this study is to describe a simple and reliable diagnostic maneuver that allows for the rapid differentiation of atypical AV nodal reentrant tachycardia (AVNRT) from other causes of long RP tachycardia. Long RP tachycardias may be caused by atypical AVNRT, orthodromic reciprocating tachycardia (ORT) involving a slowly conducting retrograde accessory pathway, or atrial tachycardia. The differentiation of atypical AVNRT from ORT or atrial tachycardia may be difficult, especially when the differential diagnosis includes a posteroseptal accessory pathway or an atrial tachycardia arising in the posteroseptal right atrium. METHODS AND RESULTS: Twelve patients with atypical AVNRT, 21 with ORT, and 12 with an atrial tachycardia diagnosed using conventional criteria were enrolled in this study. The atrial-His (AH) interval was measured at the His-bundle position during the tachycardia and during atrial pacing from the high right atrium at the tachycardia cycle length in the setting of sinus rhythm. In patients with atypical AVNRT, the mean AH interval was 69 69 msec +/- 50 msec (+/- SD) longer during high right atrial pacing than during the tachycardia (P < 0.001). In 10 of 12 patients with atypical AVNRT, the AH interval during atrial pacing was more than 40 msec longer than the AH interval measured during the tachycardia. In contrast, in patients with ORT or atrial tachycardia, the differences in AH interval between atrial pacing and tachycardia were never more than 20 and 10 msec, respectively. CONCLUSION: The difference in the AH interval between atrial pacing and the tachycardia allows a simple and rapid means of differentiating atypical AVNRT from other types of long RP tachycardias.