Patient

• 72-year-old man
• Ingenio pacemaker (Boston Scientific)
• ATR episodes recorded in the device memory

Tracing

• oversensing of a very fast signal in the atrial channel (viewable at the ventricular channel level but not sensed) saturating the baseline
• entry counter filled (programmed at 8); duration begins; acceleration of the ventricular pacing rate
• switch to an asynchronous mode

Comments

• this tracing corresponds to the recording of a 50 Hz source and not to a real atrial arrhythmia
• it is essential to systematically verify all episodes recorded in the device memory
• analysis of the EGMs can sometimes correct an erroneous diagnosis concluded by the device
• the solution in this patient is to identify and eliminate the source of the interference