Pacemaker

Question 1

Hystereisis

Answer 1

Hysteresis promotes intrinsic activity below the programmed Lower Rate. It prevents the device from overriding slow, but appropriate, intrinsic rhythms that may develop from extended periods of inactivity such as sleep
Normal lower rate limit set at 60 but it will allow intrinsic rate to a lower limit that is set (at say 50) until it actually will pace…

Question 2

Permanent AF

Answer 2

VVI only - no need for Dual chamber pacing

Question 3

Permanent AF

Answer 3

do not DCCV - do rate control strategy

Question 4

Asynchronous pacing

Answer 4

No sensing

AOO, VOO, DOO - PPM dependent patients undergoing surgery with cautery

Question 5

SND and no AVB

Answer 5

AAI, AAIR, DDD, DDDR

mode switch between AAI and DDD (only DDD when V-pacing needed - otherwise lets AAI pacing and native V rhythm through

Question 6

SND with AVB

Answer 6

DDD/DDDR

Question 7

DDD/DDDR

Answer 7

provides AV synchrony in patients with AVB

Question 8

Rate responsiveness

Answer 8

inc’d pacing on demand in patients with chronotropic incompetence

Question 9

DDD

Answer 9

atrial pacing when intrinsic atrial rate

Question 10

PVARP=post ventricular atrial refractory period

Answer 10

any atrial event that occurs here counts for mode switching but isn’t tracked and v-paced

Question 11

PPM EP Testing

Answer 11

HV interval (normal 35-55)
WPW - short HV interval (<35)
long HV interval - distal conduction dz - needs PPM

AH interval (normal 40-140) - prolonged = vagal, BB, first deg AVB

Mobitz I - prolonging AH until A with no H then shorter AH again

Mobitz II - constant AH followed by QRS until AH with no QRS after.

2:1 - A and H with dropped ventricular signal every other beat

Question 12

Managed ventricular pacing

Answer 12

Allows for loss of AV conduction for one cycle to avoid excess v-pacing