Lead Monitor Feature
Lead Monitor measures the impedance of the connected lead(s) to see if it falls within the programmed range for a stable lead. Should the lead impedance fall outside of the acceptable impedance range, a Lead Warning will appear in the observations window of the Quick Look™ screen the next time the device is interrogated.
This feature can be found in some Medtronic Pacemaker and CRT-P devices. Please go to manuals.medtronic.com or consult with your local Medtronic representative regarding device models available in your geography.
Lead Monitor is shipped to Configure or Monitor Only (applies to unipolar only models).
Programmable parameters include:
- Atrial/Ventricular Lead Monitor – Monitors lead impedance in the atrium or right ventricle; option to provide unipolar pacing for an out-of-range lead; provides automatic configuration of polarity at implant. Note: Ventricular Lead Monitor only is available is Advisa SR MRI™.
- Lead Monitor settings
- Configure: Provides automatic configuration of polarity at implant.
- Adaptive: Out-of-range lead impedance measurements result in a Quick Look Screen Lead Warning message, and a change from bipolar to unipolar lead configuration.
- Monitor Only (nominal setting): Out-of-range lead impedance measurements result in a Quick Look Screen Lead Warning message.
- Off (only in Adapta pacemakers): Out-of-range lead impedance measurements do not result in either a Lead Warning message or a polarity switch.
- Lead Monitor settings
- Notify If < (Less Than) – Minimum boundary for acceptable atrial and ventricular lead impedance. Programmable in Advisa and Consulta devices and fixed at 200 ohms in Adapta pacemakers.
- Notify If > (Greater Than) – Maximum programmable boundary for acceptable atrial and ventricular bipolar lead impedance.
- Monitor Sensitivity – Number of high or low out-of-range impedance paces needed to define a lead warning.
To program this feature, go to Params -> Pace/Sense Polarity under the Atrial or Right Ventricular Lead.
Lead Monitor should not be programmed to Adaptive for patients with 2 concomitant devices (a pacemaker and an implantable defibrillator). When a prevalence of out-of-range lead impedance paces is detected, the monitor automatically reprograms the selected lead(s) to unipolar polarity. Pacing in the unipolar configuration may cause the defibrillator either to provoke inappropriate therapy or to withhold appropriate therapy.
The Lead Monitor feature monitors lead impedance to see if it falls within the programmed impedance range for a stable lead. The three programmable values under Atrial or Ventricular Lead Monitor are as follows:
- Configure – Designed to provide automatic configuration of polarity during implant.
- Adaptive –
- Switches pacing and sensing polarity from bipolar to unipolar when the pacemaker detects a specific number of high or low impedance paces on a bipolar lead. The Lead Monitor setting changes to Monitor Only when a polarity switch to unipolar occurs on a bipolar lead.
- Provides automatic polarity configuration when selected prior to implant.
- Monitor Only – Monitors either unipolar or bipolar paces to determine if they are out of range but does not switch polarity when an out-of-range lead is indicated.
Lead Monitor is activated at lead connection, and it is automatically set to its operating value of Monitor Only or Adaptive at the end of Implant Detection. When Lead Monitor is set to Adaptive or Monitor Only and a lead is determined to be out of range, the pacemaker issues a lead warning that appears on the programmer screen at the next interrogation.
Sources: Medtronic Adapta™/Versa™/Sensia™ Reference Guide; Medtronic Consulta™ CRT-P Clinician Manual.