{"doi":"10.1093/europace/euaf089","title":"An <i>in silico</i> guide for ventriculo-ventricular delay programming for left bundle branch-optimized cardiac resynchronization therapy","abstract":"AIMS: Left bundle branch pacing (LBBP)-optimized cardiac resynchronization therapy (LOT-CRT) can improve left ventricular (LV) activation when LBBP alone or conventional biventricular pacing are ineffective. However, the optimal programming settings for ventriculo-ventricular delay (VVD) for LOT-CRT are unknown. We aim to investigate how to optimally program VVD for LOT-CRT in the presence of various LV conduction substrates using computational modelling. METHODS AND RESULTS: We simulated ventricular activation on 24 anatomies and validated the model against clinical data. Diffuse LV conduction system and intra-myocardial delay were simulated by slowing the conduction velocity of the LV His-Purkinje system and myocardium, respectively, alone or in combination with proximal left bundle branch block (LBBB). We simulated LOT-CRT with selective or myocardial capture (LV septal pacing, LVSP) with VVD ranging between -100 ms (LBBP/LVSP ahead) and +100 ms [LV epicardial lead (LVepiP), ahead]. Response was quantified with 95% LV activation times (LVAT95). In the presence of diffuse LV conduction system delay, the optimal VVD for LOT-CRT was always negative (LBBB: -42.5 ± 6.6 ms; no LBBB: -36.2 ± 5.6 ms), as delivering LBBP ahead of LVepiP compensates for the slow LV His-Purkinje. In the presence of LV intra-myocardial disease, the shortest LVAT95 with LOT-CRT was achieved by pacing the coronary sinus LV first (optimal VVD for LBBB: 23.3 ± 8.5 ms; no LBBB: 79.2 ± 18.0 ms). The type of capture for LOT-CRT affected the optimal VVD, with myocardial capture favouring negative VVDs (LVSP ahead). CONCLUSION: The optimal VVD for LOT-CRT depends on the mechanism of delayed LV activation and type of capture achieved, highlighting the importance of VVD optimization.","journal":"EP Europace","year":2025,"id":523411,"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":4,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9553,"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":1395836,"name":"Jack Samways","orcid":"0000-0001-9090-9610","position":1,"is_corresponding":false},{"id":1395837,"name":"Akriti Naraen","orcid":"0000-0002-1681-2981","position":2,"is_corresponding":false},{"id":1395838,"name":"Nadine Ali","orcid":"0000-0002-3169-4776","position":3,"is_corresponding":false},{"id":1202373,"name":"Matthew Shun‐Shin","orcid":"0000-0002-1179-0867","position":4,"is_corresponding":false},{"id":572626,"name":"Karli Gillette","orcid":"0000-0002-0420-5375","position":5,"is_corresponding":false},{"id":715275,"name":"Christopher A. Rinaldi","orcid":"0000-0002-3930-1957","position":6,"is_corresponding":false},{"id":1395839,"name":"Ahran Arnold","orcid":"0000-0002-7597-0170","position":7,"is_corresponding":false},{"id":353925,"name":"Gernot Plank","orcid":"0000-0002-7380-6908","position":8,"is_corresponding":false},{"id":353926,"name":"Edward J. Vigmond","orcid":"0000-0003-1388-3589","position":9,"is_corresponding":false},{"id":748806,"name":"Zachary I. Whinnett","orcid":"0000-0002-2775-5126","position":10,"is_corresponding":false},{"id":328101,"name":"Steven Niederer","orcid":"0000-0002-4612-6982","position":11,"is_corresponding":false},{"id":638057,"name":"Marina Strocchi","orcid":"0000-0003-1312-251X","position":0,"is_corresponding":true}],"reference_count":38,"raw_metadata":null,"created_at":"2026-07-19T02:50:03.004175Z","pmid":"40394990","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":[]}