Tracking preference as unusual trigger of pacemaker-mediated tachycardia in a resynchronization device

Area of Science:

• Electrophysiology
• Cardiology
• Medical Device Technology

Background:

• A 59-year-old female patient with a history of congestive heart failure (CHF) and a biventricular cardioverter-defibrillator presented with symptoms of worsening heart failure.
• Cardiac resynchronization therapy (CRT) devices are used to manage CHF by coordinating ventricular contractions.

Observation:

• Telemetry monitoring revealed multiple self-terminated episodes of rapid ventricular pacing.
• These episodes were consistent with pacemaker-mediated tachycardia (PMT).
• All PMT episodes were initiated by three consecutive ventricular extrasystoles.

Findings:

• The "tracking preference" algorithm, intended to optimize biventricular pacing, was found to be enabled in the patient's device.
• This algorithm setting inadvertently reduced the post-ventricular atrial refractory period (PVARP).
• The shortened PVARP created a condition conducive to the initiation of PMT by ventricular extrasystoles.

Implications:

• The "tracking preference" algorithm in CRT devices can be a potential trigger for PMT, especially in the presence of ventricular ectopy.
• Clinicians should carefully consider the programming of CRT devices, including the "tracking preference" setting and PVARP, to prevent PMT.
• Understanding device algorithms is crucial for managing complex pacemaker-related arrhythmias in patients with heart failure.