Timing Intervals

Question 1

Which interval prevents double counting of atrial events?

Answer 1

Atrial Blanking

Question 2

What is the nominal setting for the PAV and SAV?

Answer 2

• PAV = 150ms

- SAV = 120ms

Question 3

The Atrial Blanking period begins with an atrial or ventricular event?

Answer 3

atrial event

Question 4

What is the purpose of the Post Atrial Ventricular Blanking (PAVB) period?

Answer 4

• to prevent crosstalk from AP to ventricular channel

- is part of the ventricular EGM

Question 5

What event triggers the Post Atrial Ventricular Blanking (PAVB) period?

Answer 5

an Atrial Pace (AP)

Question 6

What is the term for when a lead in one chamber senses an intrinsic cardiac event of a different chamber?

Answer 6

far-field

Question 7

What is the term for when a lead in one chamber senses a Paced event of a different chamber?

Answer 7

cross-talk

Question 8

What is the definition of Far-Field?

Answer 8

when a lead in one chamber senses an intrinsic cardiac event of a different chamber

Question 9

What is the definition of Cross-Talk?

Answer 9

when a lead in one chamber senses a Paced event of a different chamber and may inhibit a needed pace

Question 10

What is the purpose of the Post Ventricular Atrial Blanking (PVAB) period?

Answer 10

• prevents Atrial sensing of vent events

- prevents far-field R-wave sensing

Question 11

What is the purpose of the Post Ventricular Atrial Refractory Period (PVARP)?

Answer 11

• to prevent rapid pacing of the ventricles in response to atrial tachyarrhythmias
• prevents PMT

Question 12

What components make up the Total Atrial Refractory Period (TARP)?

Answer 12

SAV and PVARP

Question 13

How does PVARP prevent PMT?

Answer 13

• atrial events occurring in this period are sensed but not tracked so they don’t reset the SAV/PAV timer
• no tracking = no high rate pacing of the ventricles

Question 14

What are the causes of Pacemaker Mediated Tachycardia?

Answer 14

• PVC cause retrograde P-wave that is tracked
• loss of atrial capture
• atrial undersensing
• atrial oversensing

Question 15

What is the purpose of the Ventricular Refractory Period (VRP)?

Answer 15

• prevents T-wave oversensing

Question 16

What is the purpose of the Ventricular Blanking (VB) period?

Answer 16

• prevents double counting of ventricular events

Question 17

What is the purpose of the Total Atrial Blanking (TAB) period?

Answer 17

atrial events in this period are ignored and not counted for arrhythmia detection purposes

Question 18

What is the Total Atrial Refractory Period (TARP)?

Answer 18

• the highest rate device will track atrial events in the ventricles before 2:1 block occurs

Question 19

What will happen if the below occurs:

- upper tracking rate < atrial rate < TARP rate

Answer 19

• Pacemaker Wenchebach will occur
• the PAV will get longer until an atrial event falls into the refractory period (AR) and is not tracked and paced by the ventricles

Question 20

What will happen if the below occurs:

upper tracking interval < TARP interval

Answer 20

• Pacemaker Wenchebach will occur

- the PAV will get longer until an atrial event falls into the refractory period (AR) and is not tracked (no VS/VP)

Question 21

What will happen if the below occurs:

TARP < upper tracking interval

Answer 21

• 2:1 block will occur

- every other atrial event will fall into refractory (AR) and not be tracked by the ventricles (no VS/VP)

Question 22

What will happen if the below occurs:

TARP rate < atrial rate

Answer 22

• 2:1 block will occur

- every other atrial event will fall into refractory (AR) and not be tracked by the ventricles (no VS/VP)

Question 23

What will happen if the below occurs:

atrial rate < TARP rate and upper tracking rate

Answer 23

1:1 tracking (this is the goal)

Question 24

The Upper Tracking Rate should be programmed _______ than the TARP rate by __________?

Answer 24

• lower

- by at least 30bpm

Question 25

What happens to the HR when 2:1 block occurs?

Answer 25

the ventricular HR drops to half of the atrial rate, causing possible negative symptoms