VAERP measurement is defined as the longest premature coupling interval that fails to conduct retrogradely to the atrium.

VAERP measurement is defined as the longest premature coupling interval that fails to conduct retrogradely to the atrium.

• A. Shortest VA conduction time
• B. Longest VA conduction time
• C. Longest premature coupling interval that fails to conduct retrogradely to the atrium
• D. Atrial refractory period

Answer: (C)

VAERP measures how far back in time you can space a ventricular premature beat before it fails to conduct retrogradely to the atrium. In an EP study, you pace the ventricle and deliver premature stimuli at progressively longer coupling intervals. If the interval is too short, the ventriculoatrial pathway is refractory and no atrial activation occurs; as you lengthen the interval, retrograde conduction may begin, producing an atrial response. The longest coupling interval that still fails to cause atrial activation is the VAERP, reflecting the refractory properties of the ventriculoatrial conduction pathway. This is different from the atrial refractory period or from simply measuring retrograde conduction time once conduction is established—the latter are not what VAERP quantifies.

VAERP measures how far back in time you can space a ventricular premature beat before it fails to conduct retrogradely to the atrium. In an EP study, you pace the ventricle and deliver premature stimuli at progressively longer coupling intervals. If the interval is too short, the ventriculoatrial pathway is refractory and no atrial activation occurs; as you lengthen the interval, retrograde conduction may begin, producing an atrial response. The longest coupling interval that still fails to cause atrial activation is the VAERP, reflecting the refractory properties of the ventriculoatrial conduction pathway. This is different from the atrial refractory period or from simply measuring retrograde conduction time once conduction is established—the latter are not what VAERP quantifies.