User Manual Part 2

5-8
PACING THERAPIES
BASIC PARAMETERS
The maximal CRT benefit can be achieved when biventricular stimulation
is delivered. Atrial pacing and adaptive-rate modes may be appropriate for
patients who also ex pe rience bradycardia.
WARNING: Do not use atrial-only modes in patients with heart failure
because such modes do not provide CRT.
NOTE: The safety and effectiveness of CRT was evaluated in clinical studies
using the VDD mode. Use medical discretion when programming the pulse
generator to pacing modes other than VDD.
NOTE: Atrial pacing may prolong interatrial conduction, desynchronizing
right and left atrial contractions. The effect of atrial pacing on CRT has not
been studied.
DDD and DDDR
• Could be appropriate for heart failure patients with sinus bradycardia
since DDD(R) can provide atrial-synchronous biventricular pacing at rates
above the LRL and AV-sequential biventricular pacing at the LRL or
sensor-indicated rate—DDDR
• DDD mode may be preferred over VDD mode for patients with sinus
bradycardia or atrial rates below the LRL to preserve AV synchrony with
CRT delivery
DDI and DDIR
• May not be appropriate for heart failure patients with normal sinus activity
• Could be appropriate for heart failure patients who have no underlying
intrinsic sinus rhythm but might experience episodes of atrial
tachyarrhythmias such as brady-tachy syndrome
• Provide AV-sequential biventricular pacing only at the LRL or
sensor-indicated rate, DDIR, in the absence of sinus activity
• During periods of intrinsic atria l activity abo ve the LRL,
non-atrial-synchronous biventricular pacing is delivered at the LRL or
sensor-indica ted rat e
- DRAFT -