Risks of inappropriate use of an algorithm favouring intrinsic conduction

Area of Science:

• Cardiology
• Biomedical Engineering

Background:

• An 80-year-old woman presented with pre-syncopal episodes due to transient atrioventricular (AV) block.
• A dual-chamber pacemaker (Boston Scientific Accolade MRI DR) was implanted to manage the condition.

Observation:

• The pacemaker was programmed with the RYTHMIQ® algorithm to minimize inappropriate ventricular pacing, given residual AV conduction.
• A month post-implantation, the patient developed severe asthenia and bradycardia (46-48 bpm).

Findings:

• Telemetry revealed a complete heart block (III-degree AV block) with a junctional escape rhythm.
• This indicated a failure of the RYTHMIQ® algorithm to appropriately adapt, leading to the adverse event.

Implications:

• This case underscores the critical need for vigilant monitoring of pacemaker algorithm status, including RYTHMIQ®, post-implantation.
• Ensuring proper algorithm function is crucial for preventing potentially life-threatening bradycardia and optimizing patient outcomes in cardiac device management.