Pacing Modes – Advantages and Disadvantages

15/11/10

AAI

- atrial pacing and sensing

- - if no electrical impulse sensed then pacemaker will pace @ a pre-programmed rate

- if electrical impulse sensed then pacing inhibited

VVI

- ventricular pacing and sensing

- if no electrical impulse sensed then pacemaker will pace @ a pre-programmed rate

- if electrical impulse sensed then pacing inhibited

- asynchronous pacing

DDD

- both atrium and ventricle both sensed and paced

- if both SA and AV node functioning then pacemaker will just sense

- if either atrium or ventricle not conveyed -> pacemaker will take over

Advantages Disadvantages

AAI - single lead - unable to use in AF

- AV synchrony maintained - ventricular bradycardia may occur

- able to assess ST changes in presence of a high grade AV

block

- instability of single atrial lead

- higher risk of thin atrial wall

VVI - requires a single lead - AV synchronicity lost

- useful in presence of AF and high grade - unable to assess ST changes

AV block - loss of atrial kick

- risk of pacemaker syndrome

DDD - AV synchronicity maintained - pacemaker mediated endless-loop

- use in AF and high grade AV block tachycardia possible

- heart rate responsive - pacemaker syndrome if incorrectly

setup

- may not be able to assess ST’s

Jeremy Fernando (2010)