far-field sensing
Detection of electrical activity from distant cardiac chambers by device leads not positioned in those chambers.
Full Definition
Far-field sensing occurs when pacemaker or ICD leads inappropriately detect electrical signals originating from cardiac chambers other than where the lead is positioned. Most commonly, this involves atrial leads sensing ventricular depolarization (far-field R-wave sensing) or ventricular leads detecting atrial activity. This phenomenon can result in inappropriate device responses such as pacing inhibition, mode switching, or false arrhythmia detection. Far-field sensing is influenced by lead positioning, sensitivity settings, cardiac anatomy, and signal amplitude. Management strategies include adjusting sensitivity parameters, modifying blanking periods, or lead repositioning in severe cases. Proper recognition of far-field signals on device electrograms is essential for optimal device programming and troubleshooting.
Usage
Usage note: Specify which chambers are involved; distinguish from true oversensing of non-cardiac signals.
In Context
- "Far-field sensing of ventricular activity by the atrial lead caused inappropriate mode switching." — Device interrogation analysis
- "Sensitivity adjustment resolved far-field R-wave sensing without compromising P-wave detection." — Device optimization report