RV Sense Polarity Feature
RV Sense Polarity is a feature available to program the RV sensing vector between true bipolar and integrated bipolar. It offers a noninvasive option to troubleshoot T wave oversensing and/or a reduction in R wave amplitudes. It is only available in ICDs and requires that a true bipolar lead be implanted.
This feature can be found in some Medtronic ICD and CRT-D devices. Please go to manuals.medtronic.com or consult with your local Medtronic representative regarding device models available in your geography.
The RV sensing vector is programmable via the RV Sense Polarity parameter. RV Sense Polarity can be programmed to either Bipolar (tip-to-ring) or Tip to Coil (integrated bipolar).
To program this feature go to Params -> Pacing…
The RV Sense Polarity feature determines which electrodes the RV lead uses to sense. It can be programmed to either true bipolar, sensing between the tip and ring electrodes, or integrated bipolar, sensing between the tip and RV coil electrodes. Changing the RV Sense Polarity between these two configurations may change the amplitude of the RV sensed EGM. This change may result in an increase or decrease in the R wave and T wave amplitude measurement depending on lead position. This feature can offer a noninvasive option for troubleshooting T wave oversensing.
Caution should be taken in changing the RV Sense Polarity because the ability of the device to detect and sense fine VF is changed. Reevaluation of the ability of the device to sense VF should be considered through defibrillation testing.
- This feature does not work for dedicated integrated bipolar defibrillation leads, since there is no RV ring electrode.
- Note that changing the RV sense vector will not affect the RV pace polarity.
- The ventricular sensing electrodes included in Sensing Test measurements depend on the programmed RV Sense Polarity value.
In the R wave trend graph below, the Bipolar R wave measurement trends at approximately 4mV. The sensing vector was then reprogrammed from Bipolar to Tip to Coil sensing, resulting in the increase in measured R wave amplitude. The R wave was then measured to be approximately 12mV in the Tip to Coil sensing configuration.
Sources: Medtronic Protecta™ XT DR Clinician Manual; Medtronic Protecta™ XT CRT-D Clinician Manual.