Evidence map›Paper›PMID 41982983›Full record

ArticleEuropean heart journal. Case reports2026

Exercise-induced atrioventricular block in a patient with a pacemaker: a functional consequence of AV search algorithms-a case report.

Clara Nuevo-Gallardo, José Miguel Rojo-Pérez, Luis Javier Doncel-Vecino, Lorenzo Muñoz-Santos, Antonio Chacón-Piñero

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In one paragraph

Article in European heart journal. Case reports, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

5 authors.

Clara Nuevo-GallardoCardiology Department, University Hospital of Badajoz, Avenida de Elvas s/n, Badajoz 06006, Spain.ORCID https://orcid.org/0009-0005-9594-6417
José Miguel Rojo-PérezCardiology Department, University Hospital of Badajoz, Avenida de Elvas s/n, Badajoz 06006, Spain.
Luis Javier Doncel-VecinoCardiology Department, University Hospital of Badajoz, Avenida de Elvas s/n, Badajoz 06006, Spain.
Lorenzo Muñoz-SantosArrythmia Unit, Cardiology Department, University Hospital of Badajoz, Avenida de Elvas s/n, Badajoz 06006, Spain.
Antonio Chacón-PiñeroArrythmia Unit, Cardiology Department, University Hospital of Badajoz, Avenida de Elvas s/n, Badajoz 06006, Spain.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Background: Algorithms designed to promote intrinsic atrioventricular (AV) conduction in dual-chamber pacemakers aim to reduce unnecessary right ventricular pacing and its long-term adverse effects. The AV Search+ algorithm periodically prolongs the AV delay to facilitate native conduction and is particularly useful in non-pacemaker-dependent patients. However, under certain conditions, such algorithms may lead to unexpected disturbances in AV synchrony, especially during exercise. Case summary: A 65-year-old woman with symptomatic second-degree AV block (Mobitz II) underwent dual-chamber pacemaker implantation. During follow-up, she developed progressive exertional dyspnoea. Exercise stress testing revealed a paradoxical decrease in heart rate during increasing workload with reproduction of symptoms. Programmer-monitored exercise testing demonstrated a functional 2:1 AV block caused by atrial undersensing, as atrial depolarizations occurred within the post-ventricular atrial refractory period during AV Search+-mediated AV delay prolongation. Deactivation of the AV Search+ algorithm restored stable 1:1 AV conduction during exercise and resulted in complete symptom resolution. Conclusion: This case highlights a rare but clinically relevant complication of AV conduction search algorithms in dual-chamber pacemakers. Although these algorithms effectively reduce ventricular pacing, inappropriate interactions between prolonged AV delays and atrial refractory periods may result in symptomatic functional AV block, particularly during exercise and in patients with advanced AV conduction disease. Exercise testing with device interrogation is a key diagnostic tool in pacemaker patients with exertion-related symptoms, and individualized device programming is essential to ensure optimal clinical outcomes.

Indexed as

Atrioventricular blockAtrioventricular search algorithmCase reportDDD pacemakerExercise testingPost-ventricular atrial refractory period

Identifiers

PMID41982983
PMCPMC13075946

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