20.500.12556/DiRROS-30011 AV-optimized conduction system pacing for treatment of AV dromotropathy a randomized, cross-over study Background: Severe first-degree atrioventricular (AV) block may produce symptoms similar to heart failure due to AV dyssynchrony, a syndrome termed AV dromotropathy. According to guidelines, it should be considered for permanent pacemaker implantation, yet evidence supporting this treatment is scarce. Objectives: This study aimed to determine the impact of AV-optimized conduction system pacing (CSP) in patients with symptomatic severe first-degree AV block and echocardiographic signs of AV dyssynchrony. Methods: Patients with symptomatic first-degree AV block (PR > 250 ms), preserved left ventricular ejection fraction, narrow QRS, and AV dyssynchrony were included in the study. In a single-blind cross-over design, patients were randomized to AV sequential CSP or backup VVI pacing with a base rate of 40 bpm. We compared exercise capacity, echocardiographic parameters, and symptom occurrence at the end of 3 months of each period. Results: Fourteen patients completed the study. During the AV-optimized CSP compared to the backup pacing period, patients achieved a higher workload on exercise test (147.2 ± 50.9 vs. 140.7 ± 55.8 W; p = .032), with a trend towards higher peak VO2 (23.3 ± 7.1 vs. 22.8 ± 7.1 mL/min/kg; p = .224), and higher left ventricular stroke volume (LVSV 74.5 ± 13.8 vs. 66.4 ± 12.5 mL; p < .001). Symptomatic improvement was recorded, with fewer patients reporting general tiredness and 71% of patients preferring the AV-optimized CSP (p = .008). Conclusions: AV-optimized CSP could improve symptoms, exercise capacity and LVSV in patients with severe first-degree AV block AV coupling AV dromotropathy AV dyssynchrony conduction system pacing first‐degree AV block true false true Angleški jezik Ni določen Neznano 2026-06-11 13:08:16 2026-06-11 13:08:17 2026-06-12 03:54:45 0000-00-00 00:00:00 2024 0 0 str. 1340-1350 iss. 7 Vol. 35 2024 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 616.1:602.621 1045-3873 10.1111/jce.16268 203663107 RAZ_Zupan_Meznar_Anja_2024.pdf RAZ_Zupan_Meznar_Anja_2024.pdf 1 0A360DEC8BBF0C5F9C7A441A9CE71C27 d5d75b5653c54812fc161a3146138c7b5eb6a25afe48aea6dfed1c2355048057 05984ae3-6586-11f1-9215-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=45229 https://onlinelibrary.wiley.com/doi/10.1111/jce.16268 1 d9aa2410-6585-11f1-9215-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=45228 Univerzitetni klinični center Ljubljana 0 0 0