Extrastimulus pacing from the HRA catheter is used to determine which parameters?

Extrastimulus pacing from the HRA catheter is used to determine which parameters?

• A. AERP and AVNERP
• B. PR interval and QRS duration
• C. QT interval and heart rate
• D. AV nodal effective refractory period only

Answer: (A)

Extrastimulus pacing from the high right atrium tests how-ready the atrial tissue and the AV node are to conduct a premature impulse. By delivering a drive train of beats and then a premature atrial stimulus at progressively shorter coupling intervals, you map the recovery properties of the pathway. The atrial effective refractory period is the interval below which the atrial tissue cannot be re-excited with propagation, while the AV nodal effective refractory period is the interval below which a premature atrial impulse cannot conduct through the AV node to the ventricles. Measuring both gives you the AERP and the AV nodal ERP, which is exactly what this pacing method assesses. Other parameters like PR interval and QRS duration reflect baseline conduction times rather than refractory properties, and QT interval with heart rate are not determined by this extrastimulus testing.

Extrastimulus pacing from the high right atrium tests how-ready the atrial tissue and the AV node are to conduct a premature impulse. By delivering a drive train of beats and then a premature atrial stimulus at progressively shorter coupling intervals, you map the recovery properties of the pathway. The atrial effective refractory period is the interval below which the atrial tissue cannot be re-excited with propagation, while the AV nodal effective refractory period is the interval below which a premature atrial impulse cannot conduct through the AV node to the ventricles. Measuring both gives you the AERP and the AV nodal ERP, which is exactly what this pacing method assesses.

Other parameters like PR interval and QRS duration reflect baseline conduction times rather than refractory properties, and QT interval with heart rate are not determined by this extrastimulus testing.