Proarrhythmic effect of automatic threshold testing algorithm in dual chamber devices.

Area of Science:

• Cardiology
• Biomedical Engineering
• Electrophysiology

Background:

• Auto-threshold testing (ATT) in dual chamber cardiac devices necessitates AV delay shortening, potentially causing atrial pressure increases and arrhythmias.
• Near simultaneous atrioventricular pacing during ATT may trigger atrial arrhythmias.

Purpose of the Study:

• To determine the prevalence of atrial arrhythmias, specifically atrial fibrillation (AF), induced by ATT in Abbott dual chamber pacemakers.
• To investigate the association between ATT and the occurrence of AF in patients with cardiac devices.

Main Methods:

• A retrospective review of device clinic records for patients with dual chamber Abbott pacemakers/ICDs was conducted.
• ATT-induced AF was identified by new appropriate mode switch episodes during ATT operation.
• Unstable auto-capture trends were defined by significant capture threshold deviations (>1V) unrelated to routine testing.

Main Results:

• Of 118 patients with active ventricular ATT, 78 experienced mode switch episodes, and 6 developed AF.
• Patients with unstable auto-capture trends showed a significantly higher incidence of ATT-induced AF (18%) compared to those with stable trends (P=.0001).
• Atrial arrhythmias were more frequently associated with ATT in patients with unstable trends.

Conclusions:

• Ventricular ATT in dual chamber Abbott devices is linked to AF induction, with an observed prevalence exceeding 5%.
• Patients exhibiting erratic ventricular ATT trend results have a higher likelihood of developing AF.
• The findings suggest a need for careful monitoring during ATT to mitigate the risk of induced atrial arrhythmias.