Ventricular Safety Pacing (VSP) Feature

In a dual chamber device with atrial and ventricular pacing and ventricular sensing, the device may sense an atrial pacing pulse on the ventricular channel and inhibit ventricular pacing (crosstalk). When inhibition of ventricular pacing occurs, the device may not provide full ventricular support. Ventricular Safety Pacing (VSP) detects crosstalk by monitoring for nonphysiologic ventricular sensed events and responds by pacing the ventricle.

This feature can be found in some Medtronic Pacemaker, ICD, CRT-P, and CRT-D devices. Please go to or consult with your local Medtronic representative regarding device models available in your geography.

VSP is available when the device is operating in the DDDR, DDD, DDIR, DDI, DVIR, and DVI modes. It is nominally programmed On.

To program this feature in pacemakers, go to Params -> Additional Features.

To program this feature in ICDs, go to Pacing -> Params -> Additional Features.

Warning: Always program Ventricular Safety Pacing (VSP) to On for pacemaker-dependent patients. Ventricular Safety Pacing prevents ventricular asystole due to inappropriate inhibition of ventricular pacing caused by oversensing in the ventricle.

Ventricular Safety Pacing functions to prevent ventricular asystole due to inappropriate inhibition of ventricular pacing. Such inhibition may be caused by crosstalk or ventricular oversensing.

By triggering ventricular pacing after an oversensed ventricular event, the device maintains its ability to provide full ventricular support.

After an atrial paced event, the device begins a 110 ms safety pacing interval. Any ventricular sensed event that occurs within the 110 millisecond window will result in a ventricular pace at the end of the 110 millisecond window. Atrial sensed (AS) events do not initiate a Ventricular Safety Pacing interval. The following diagram provides an overview for Ventricular Safety Pacing.

The example EKG below demonstrates VSP in the 1st and 5th EKG complexes.


Sources: Medtronic Adapta/Versa/Sensia Reference Guide; Medtronic Consulta CRT-P Clinician Manual;Medtronic Protecta XT DR Clinician Manual; Medtronic Protecta XT CRT-D Clinician Manual.

Last updated: 
27 Mar 2013