User's Manual

Pacing and Sensing Functions

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— The incremental decrease of the pacing amplitude continues

until loss of capture is measured (meaning the pace is

ineffective). The last effective pacing amplitude that is measured

is accepted and saved.

— After the first ineffective pace is detected, either the AV delay

(for atrial-controlled pacing) or the basic rate (for ventricular-

controlled pacing) is changed with the subsequent pace.

If again no stimulus response is measured, the ineffectiveness of

the pacing is confirmed.

— A safety pulse with maximum pulse width is delivered after every

ineffective ventricular pace. This produces continuously effective

pacing.

Verification of the Stimulus Response

Purpose

This function allows the pacing amplitude to be continuously verified.

Verification of the stimulus response is possible for a ventricular rate of

up to 110 bpm.

Description

The pacing effectiveness is verified after each ventricular stimulus.

— When pacing is effective, any current settings are retained.

— When pacing is ineffective, a safety pace with a higher level of

energy is delivered after 130 ms at the latest. This is done at the

same amplitude but a greater pulse width.

— When a series of 3 consecutive ventricular paces – even after the

AV delay has been changed – does not produce effective pacing,

first the signal analysis function is started and a new threshold

search is executed.

— If pacing continues to be ineffective, the pacing amplitude is

increased in order to secure effective pacing. Due to this

automatic amplitude control, it is possible to select a smaller

safety margin, which can produce lower energy consumption

with safe pacing.

— After the monitoring interval has elapsed, the threshold search

function is automatically executed. The pacing amplitude is set

to the threshold value plus the safety margin.