Symptomatic atrioventricular block during biventricular pacing: Facing a double trouble

Area of Science:

• Cardiology
• Biomedical Engineering

Background:

• A 63-year-old female patient received a dual-chamber pacemaker for infra-hisian complete heart block.
• The patient later underwent cardiac resynchronization therapy (CRT-P) for pacing-induced cardiomyopathy, which successfully improved left ventricular function.

Observation:

• The patient experienced Far-field R wave (FFRW) oversensing in the atrial channel.
• This oversensing falsely triggered atrial tachycardia, activating an "atrial flutter response".

Findings:

• The "atrial flutter response" led to symptomatic, inadvertent atrioventricular block.
• Troubleshooting FFRW oversensing was complicated by concurrent P wave undersensing.

Implications:

• This case underscores the diagnostic and management difficulties posed by combined FFRW oversensing and P wave undersensing.
• Strategies for managing FFRW oversensing, such as adjusting post-ventricular atrial blanking or atrial sensitivity, require careful consideration in complex pacing scenarios.