Impact of sampling site on Activated Clotting Time (ACT) during cryoballoon ablation: Left atrium vs femoral sheath
- 1Technion Israel Institute of Technology, The Ruth and Bruce Rappaport Faculty of Medicine, Technion City, Haifa, Israel
- 2Division of Cardiovascular Medicine, Hillel Yaffe Medical Center, Hadera, Israel
- 3Clinical Laboratory Division, Hillel Yaffe Medical Center, Hadera, Israel
Abstract
Background: Activated clotting time (ACT) is used to monitor unfractionated heparin (UFH) during left atrial (LA) ablation procedures. Inadequate anticoagulation increases thromboembolic risk, while excessive UFH may increase bleeding. ACT can be sampled from a femoral venous sheath (ACTFV) or from oxygenated blood within the LA (ACTLA). The influence of sampling site on ACT values during atrial fibrillation ablation is unknown.
Methods: In this prospective observational study, consecutive patients undergoing cryoballoon pulmonary vein isolation received intravenous UFH. ACT was sampled sequentially from the LA and from a femoral venous sheath. All samples were analyzed on the same point-of-care ACT machine. Non-inferiority of LA relative to femoral venous sampling was tested against a 30-s margin, with agreement assessed by Cohen's kappa at 300 s and Bland-Altman analysis.
Results: Sixty-two patients were recruited (42% female; CHA2DS2-VASc 3.1 ± 1.8); 61 had paired samples. Mean ACTLA was 365 ± 83 and ACTFV was 359 ± 65 s (p = 0.455). The mean paired difference (ACTLA − ACTFV) was +6.1 s (upper one-sided 97.5% confidence limit +22.4 s), below the 30-s non-inferiority margin (p = 0.002). Bland-Altman limits of agreement were − 119 to +131 s, with significant proportional bias (β = 0.288, p = 0.017). Dichotomized at 300 s, Cohen's kappa was 0.586 (moderate concordance).
Conclusions: ACT sampling from the LA was non-inferior to femoral venous sampling within a 30-s margin, supporting the use of either sampling site during LA ablation. Despite notable variability between paired measurements, unexpected ACT values should prompt repeat testing rather than be attributed to the sampling site.
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BibTeX
@article{margolis2026impact,
title = {{Impact of sampling site on Activated Clotting Time (ACT) during cryoballoon ablation: Left atrium vs femoral sheath}},
author = {Gilad Margolis and Kirill Berezhnoi and Ofir Goldhaber and Ofer Kobo and Mark Kazatsker and Ma'anit Shapira and Rami Abu-Fanne and Ariel Roguin and Eran Leshem},
journal = {American Heart Journal Plus: Cardiology Research and Practice},
year = {2026},
month = oct,
doi = {10.1016/j.ahjo.2026.100995},
url = {https://doi.org/10.1016/j.ahjo.2026.100995},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Impact of sampling site on Activated Clotting Time (ACT) during cryoballoon ablation: Left atrium vs femoral sheath
AU - Gilad Margolis
AU - Kirill Berezhnoi
AU - Ofir Goldhaber
AU - Ofer Kobo
AU - Mark Kazatsker
AU - Ma'anit Shapira
AU - Rami Abu-Fanne
AU - Ariel Roguin
AU - Eran Leshem
PY - 2026
DA - 2026/10/24
JO - American Heart Journal Plus: Cardiology Research and Practice
DO - 10.1016/j.ahjo.2026.100995
UR - https://doi.org/10.1016/j.ahjo.2026.100995
AB - Background: Activated clotting time (ACT) is used to monitor unfractionated heparin (UFH) during left atrial (LA) ablation procedures. Inadequate anticoagulation increases thromboembolic risk, while excessive UFH may increase bleeding. ACT can be sampled from a femoral venous sheath (ACTFV) or from oxygenated blood within the LA (ACTLA). The influence of sampling site on ACT values during atrial fibrillation ablation is unknown. Methods: In this prospective observational study, consecutive patients undergoing cryoballoon pulmonary vein isolation received intravenous UFH. ACT was sampled sequentially from the LA and from a femoral venous sheath. All samples were analyzed on the same point-of-care ACT machine. Non-inferiority of LA relative to femoral venous sampling was tested against a 30-s margin, with agreement assessed by Cohen's kappa at 300 s and Bland-Altman analysis. Results: Sixty-two patients were recruited (42% female; CHA2DS2-VASc 3.1 ± 1.8); 61 had paired samples. Mean ACTLA was 365 ± 83 and ACTFV was 359 ± 65 s (p = 0.455). The mean paired difference (ACTLA − ACTFV) was +6.1 s (upper one-sided 97.5% confidence limit +22.4 s), below the 30-s non-inferiority margin (p = 0.002). Bland-Altman limits of agreement were − 119 to +131 s, with significant proportional bias (β = 0.288, p = 0.017). Dichotomized at 300 s, Cohen's kappa was 0.586 (moderate concordance). Conclusions: ACT sampling from the LA was non-inferior to femoral venous sampling within a 30-s margin, supporting the use of either sampling site during LA ablation. Despite notable variability between paired measurements, unexpected ACT values should prompt repeat testing rather than be attributed to the sampling site.
SN - 2666-6022
ER -