The
pacing threshold and impedance at the time of implantation and follow-up was noted (Tables-1-2).
It measured atrial
pacing threshold automatically and regularly every 8 or 24 h for out-of-clinic use and immediately by user initiated threshold search for in-clinic use.
This study investigated the effect of severity, distribution of CAD and left ventricular ejection fraction (LVEF) on acute ventricular
pacing threshold and lead impedance at the time of either antibradycardic pacemaker (PM) or implantable cardiac defibrillator (ICD) implantations in our institution for various indications.
By gradually increasing the pacing current until stable capture of atrial pacing was confirmed by surface ECG, the
pacing threshold of all 9 electrode positions was found.
The three parameters used are lead impedance, sensing (R-wave amplitude), and capture (
pacing threshold).
*Acceptable
pacing threshold (acute): With 0.5 ms of the pulse width, the
pacing threshold of the right atrium was ≤1.5 V and the threshold of the right ventricle was ≤1.0 V.
When the
pacing threshold was >1.5 V, the lead was repositioned.
A change in the
pacing threshold can be a sign of RV perforation by the pacemaker lead.
Pacing threshold, R wave and impedance of ventricular lead during implant were 0.7 V at 0.5 msec, 7 mV and 350 ohms, respectively.
Key words: pacemakers, longevity, pulse amplitude, pulse width,
pacing thresholdPotential complications include device dislodgement, cardiac perforation, elevated
pacing thresholds requiring device retrieval and reimplanatation, and vascular complications.