PVC Response ''Atrial Pace'' Inducing Atrial Tachycardias

Premature ventricular contractions (PVC) are common phenomenon and occasionally retrograde conduction from ventricle to atrium occurs and may cause pacemaker mediated tachycardia. In response certain Abbott (former St Jude Medical) pacemakers have a specific PVC response algorithm ''Atrial Pace''. In this algorithm the PVARP (Post Ventricular Atrial Refractory Period) is extended to 480ms but the initial 150ms of the PVARP is deemed absolute. If atrial sensed event occurs after absolute PVARP the PVARP terminates and atrial pace follows after 330ms alert period. Two case reports exists where patients atrial tachycardia were suspected to be induced by this algorithm. In Helsinki University Hospital an index patient with multiple atrial tachycardia episodes was recognized in late 2020 where the cause of the tachycardias was suspected to be the PVC response algorithm ''Atrial Pace''. After programming the algorithm from Atrial Pace to off mode the patient had none atrial tachycardias during 2021. After investigating all the patients with physiological ICD (Implantable Cardioverter Defibrillator) or CRT-D (Cardiac Resynchronization Therapy) device and analyzing remote monitoring transmissions from the year 2020 we found 25 patients with similar atrial tachycardia episodes possibly induced by the PVC response ''Atrial Pace''.