Risks of inappropriate use of an algorithm favouring intrinsic conduction

Abstract

An 80‐year‐old woman received a dual chamber pacemaker (Boston Scientific Accolade MRI DR) for pre‐syncopal episodes associated with transient II‐degree atrioventricular block type 1 and 2:1, recorded in 24‐h Holter monitoring. Due to residual AV conduction with I‐degree AV block, the pacemaker was set with the RYTHMIQ® algorithm, in order to reduce inappropriate ventricular pacing. A month later the patient started to complain of severe asthenia and bradycardia (46‐48 bpm). Telemetry‐supported pacemaker control revealed III‐degree AV block with junctional escape rhythm, unmasking missed switch of RYTHMIQ® algorithm.

Postatrial pacing ventricular refractory period, RYTHMIQTM and ventricular tachycardia response: “An Algorithmic Conflict”

“…It may be an option in patients with rare paroxysmal atrio-ventricular blocks, with caution for fast junctional rhythms that may prevent mode switching in DDD (R). 7 Furthermore, this case shows that it is not a good choice in patients with frequent PVCs. Knowing how algorithms for the avoidance of unnecessary ventricular pacing work is essential to tailor them to the patient's profile.…”

“…Like all algorithms for minimizing ventricular pacing, RYTHMIQ TM is most suitable for patients with an intact atrioventricular conduction, such as in isolated sinus node dysfunction, chronotropic insufficiency and brady‐tachycardia syndrome. It may be an option in patients with rare paroxysmal atrio‐ventricular blocks, with caution for fast junctional rhythms that may prevent mode switching in DDD(R) 7 . Furthermore, this case shows that it is not a good choice in patients with frequent PVCs.…”