4
Diagnosis
Figure 1. Differential Diagnosis for Adult Narrow
QRS Tachycardia
Narrow QRS tachycardia
(QRS duration <120 ms)
a
RP refers to the interval from the onset of surface QRS to the onset of visible P wave
(note that the 90-ms interval is defined from the surface ECG as opposed to the 70-ms
ventriculoatrial interval that is used for intracardiac diagnosis).
Modified with permission from Blomstrom-Lundqvist et al. J Am Coll Cardiol.
2003;42(8):1493-1531.
AF, AT/atrial flutter with
variable AV conduction, MAT
Regular
tachycardia
YES
NO
Visible P
waves
YES
NO
Atrial
rate greater
than ventricular
rate
AVNRT or other
mechanism with P waves
not identified
RP interval short
(RPPR)
RP <90
a
ms
AVRT, atypical AVNRT,
or AT
YES
NO
AVNRT
