What is AVERP?

What is AVERP?

• A. The longest S1 S2 interval that fails to result in ventricular depolarization
• B. The longest S1 S2 interval that captures the ventricle
• C. The shortest S1 S2 interval that fails to result in ventricular depolarization
• D. The longest S1 S2 interval that conducts to the ventricle

Answer: (A)

AVERP is the ventricle’s effective refractory period measured with an atrial Premature Stimulus. In practice, you pace the atrium (S1) and deliver a premature ventricle stimulus (S2) at progressively longer S1–S2 intervals. When S2 is very premature, the ventricle is still refractory and no depolarization occurs. As the interval lengthens, the ventricle recovers and a response may appear. The AVERP is the longest S1–S2 interval that fails to produce a ventricular depolarization. Longer intervals beyond this point will elicit capture. So the correct description is the longest interval that fails to evoke a QRS, not the longest interval that captures or the shortest that fails.

AVERP is the ventricle’s effective refractory period measured with an atrial Premature Stimulus. In practice, you pace the atrium (S1) and deliver a premature ventricle stimulus (S2) at progressively longer S1–S2 intervals. When S2 is very premature, the ventricle is still refractory and no depolarization occurs. As the interval lengthens, the ventricle recovers and a response may appear. The AVERP is the longest S1–S2 interval that fails to produce a ventricular depolarization. Longer intervals beyond this point will elicit capture. So the correct description is the longest interval that fails to evoke a QRS, not the longest interval that captures or the shortest that fails.