mode switching
Automatic pacemaker function that temporarily changes from dual-chamber to single-chamber pacing during episodes of atrial arrhythmias.
Full Definition
Mode switching is an automatic pacemaker algorithm that temporarily switches the device from a dual-chamber tracking mode (such as DDD or VDD) to a non-tracking mode (typically DDI or VVI) when it detects atrial arrhythmias, particularly atrial fibrillation or atrial flutter. This prevents the pacemaker from tracking rapid atrial rates and delivering inappropriately fast ventricular pacing, which could cause symptoms or hemodynamic compromise. The device continuously monitors atrial rate and rhythm, automatically switching modes when predefined criteria are met (such as atrial rate exceeding a programmed threshold). When the atrial arrhythmia terminates and normal sinus rhythm resumes, the pacemaker automatically returns to its original dual-chamber tracking mode. Modern devices use sophisticated algorithms to distinguish between true atrial arrhythmias and other causes of apparent rapid atrial activity, such as far-field sensing or electromagnetic interference.
Usage
Usage note: Often abbreviated as AMS in device reports and clinical documentation.
In Context
- "Mode switching episodes totaling 14.2 hours were recorded, indicating significant atrial fibrillation burden." — Device interrogation report
- "The pacemaker's mode switching algorithm prevented tracking of the patient's atrial flutter at 280 bpm." — Cardiac device clinic note