Ventricular Safety Pacing (VSR)

Question 1

How does the Ventricular Safety Pacing (VSP) algorithm work?

Answer 1

— device starts a 110ms window following an AP where if a VS falls in the window, a VP will be delivered once the window ends

Question 2

Which algorithm will provide a backup VP if a VS occurs within 110ms following an AP?

Answer 2

Ventricular Safety Pacing

Question 3

Which algorithm is characterized by short (70-110ms) PAV intervals?

Answer 3

Ventricular Safety Pacing (VSP)
- key is the short interval (< 110ms) following an AP, and both a VS and VP seen in the marker channel

Question 4

What is the purpose of the VSP algorithm?

Answer 4

To prevent cross-talk or the inhibition of a VP due to ventricular oversensing of pacing activity in the atrium

Question 5

Why would atrial undersensing in a patient with intact AV conduction cause a Ventricular Safety Pace to occur?

Answer 5

• Device undersenses a p-wave, causing an AP and the start of the 110ms VSP window
• the conduction from the intrinsic p-wave causes a VS within the window, which triggers the inappropriate delivery of a VSP

Question 6

What are the 3 most common causes of Ventricular Safety Pacing?

Answer 6

• Atrial undersensing with intact AV conduction
• ventricular oversensing
• crosstalk

Question 7

Which algorithm/feature should be suspected if the PAV is 110ms or less?

Answer 7

Ventricular Safety Pacing (VSP)