Inappropriate mode switching clarified by using a chest radiograph.

Area of Science:

• Cardiology
• Biomedical Engineering
• Electrophysiology

Background:

• Dual-chamber pacemakers are used for bradyarrhythmias like atrioventricular node disease.
• Paroxysmal atrial fibrillation can complicate pacemaker management.
• Percutaneous coronary interventions (PCI) require careful monitoring of implanted devices.

Purpose of the Study:

• To investigate the cause of abnormal pacing episodes and inappropriate mode switching during PCI.
• To identify the source of nonphysiologic recordings in a pacemaker patient.
• To evaluate potential lead-related issues causing pacemaker malfunction.

Main Methods:

• Pacemaker interrogation to assess device function and pacing parameters.
• Analysis of representative electrograms to identify signal characteristics.
• Chest radiography to evaluate lead positioning and integrity.
• Exclusion of intrinsic pacemaker malfunction through diagnostic testing.

Main Results:

• Frequent short-duration mode switching episodes were detected.
• High-frequency, nonphysiologic recordings were predominantly observed in the atrial lead.
• Excessive atrial and ventricular lead slack was identified in the right ventricular inflow.
• Intrinsic pacemaker malfunction was ruled out as the cause.

Conclusions:

• Lead-lead interaction is suspected as the cause of artifacts and oversensing.
• This interaction led to frequent, inappropriate mode switching episodes.
• Lead management and positioning are critical for preventing pacemaker malfunction, especially during invasive procedures.