From Ask Dr Wiki
How to Perform
- Overdrive HRA during tachycardia at a cycle length below the tachycardia cycle length.
- If the tachycardia terminates, reinduce
- If the tachycardia continues upon cessation of pacing, then you must categorize the VA interval (measured from the onset of the surface QRS on the first postpacing ventricular beat to the onset of the atrial electrogram on the His catheter of the return cycle as
- Fixed, meaning it is within 10 ms of the VA interval during tachycardia which is seen in ORT or AVNRT. This occurs because the timing of the atrial activation is dependent on ventricular activation
- Variable, which is seen in Atrial Tachycardia
- Pacing maneuver is not helpful differentiating AVNRT from AVRT. Only in differentiation of Atrial Tachycardia from reentrant tachycardia.
- Kadish AH, Morady F. The Response of Paroxysmal Supraventricular Tachycardia to Overdrive Atrial and Ventricular Pacing can help determine the tachycardia mechanism? JCE 1993:4:239-52