User Manual

Lumax Technical Manual 75
For CRT to be effective, ventricular pacing must occur. Therefore,
AV delays must be programmed short enough to override intrinsic
ventricular contractions. Additional information to further optimize
AV delays can be obtained with echocardiography.
CRT can be programmed ON or OFF via the programmer using
the [Ventricular Pacing] parameter. Ventricular Pacing
Configuration allows standard right ventricular [RV] (CRT = OFF)
pacing or Cardiac Resynchronization Therapy [BiV] (CRT = ON).
The Lumax HF CRT-D can provide triggered biventricular pacing.
This is a functional expansion of the basic ventricular modes
(DDD(R); DDI(R); VDI(R); VDD(R); VVI(R)) used for biventricular
pacing. The “RVs triggering” was designed to ensure CRT is
delivered even when rapid intrinsic activation interferes with
pacing, such as in the case of conducted atrial fibrillation. This
function triggers LV pacing (Vp) after intrinsic sensing (RVs) in
the right ventricle. Triggered pacing can be programmed to react
to only normal RV sensed events or to right ventricular
extrasystoles as well as normal RV sensed events. The maximum
trigger rate is normally limited by the programmed UTR
(+20bpm), but can also be programmed to function up to a
separate and higher maximum trigger rate.
V-V Delay Programming
V-V delays should be programmed based on optimization of the
echocardiographic parameter Aortic Valve Velocity Time Integral,
evaluating the full range of available delays, as was performed in
the clinical study demonstrating the safety and effectiveness of
this feature. RV pre-excitation may cause a decline of LV
function.
The V-V delay features for the Lumax HF-T devices include the
ability to program the following parameters “first chamber paced,”
which allows either the right or the left ventricle to be paced first,
and “VV delay” for setting a delay between the left and right
ventricular pacing pulses (programmable range: 0 ms … (5ms) …
100 ms).
Suggested optimization procedure:
During the V-V clinical study assessment was performed by
determining the V-V delay setting associated with the largest VTI
value. The VTI of the aortic flow is measured in the apical 5
chamber view.