{"doi":"10.1016/j.hroo.2025.05.022","title":"A “drop” in the atrioventricular conduction curve and dual-pathway electrophysiology","abstract":"Background: Atrioventricular (AV) conduction time is rate-dependent. As the atrial coupling interval (A1A2) shortens, AV conduction time (A2H2) prolongs. Thus, the AV conduction curve, plotted using A1A2 vs A2H2, is usually \"smooth\" and \"monotonic\". A \"jump\" in the curve is the current clinical criterion of dual-pathway electrophysiology, whereas a \"gap\" in the curve has also been described. Objective: This study described a new phenomenon, a \"drop\" in the AV conduction curve. The potential relationship between a drop in the AV conduction curve and the dual-pathway electrophysiology was also examined. Methods: Overall, 81 experimental records from rabbit AV nodal preparations containing the following data were analyzed: (1) had at least 1 AV conduction curve and (2) had a recording of His electrogram alternans (a validated new index of dual-pathway conduction). Most cases had intracellular action potential recordings from the AV nodal fibers. Results: Of the 81 preparations, 3 (3.7%) showed a drop in the AV conduction curve. The drops (at A1A2 = 115 ± 35 ms) always occurred after fast pathway to slow pathway (SP) transition (at 148 ± 7 ms). The drops showed an SP-fast pathway pattern in 2 of the 3 preparations and an SP-SP pattern in the remaining 1 preparation. The drops were associated with and most likely caused by the formation of intranodal/nodal-atrial reentry and its subsequent conduction. Conclusion: A new phenomenon, a drop in the AV conduction curve, has been demonstrated in this study. A drop is likely caused by the formation of intranodal/nodal-atrial reentry and its subsequent conduction.","journal":"Heart Rhythm O2","year":2025,"id":566596,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9579,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1470651,"name":"Youhua Zhang","orcid":"0000-0002-9003-2705","position":0,"is_corresponding":true}],"reference_count":22,"raw_metadata":null,"created_at":"2026-07-19T02:56:40.491968Z","pmid":"40917183","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}