Impact of international normalized ratio and activated clotting time on unfractionated heparin dosing during ablation of atrial fibrillation

Ismail Hamam, Emile G. Daoud, Jianying Zhang, Steven J. Kalbfleisch, Ralph Augostini, Marshall Winner, Shane Tsai, Troy E. Rhodes, Mahmoud Houmsse, Zhenguo Liu, Charles J. Love, Jaret Tyler, Molly Sachdev, Raul Weiss, John D. Hummel

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

Background-For ablation of atrial fibrillation, it is unclear how baseline international normalized ratio (INR) affects the dosing of unfractionated heparin (UFH). Methods and Results-A retrospective review of 170 consecutive patients undergoing atrial fibrillation ablation with baseline activated clotting time (ACT) and INR values was performed. Patients were grouped according to INR <2.0 (G<2; n=129) and INR ≥2.0 (G≥2; n=41). Clinical variables, UFH doses, and ACT values were recorded. An equation was derived to calculate the first bolus of UFH required to achieve an ACT ≥300 seconds, and this was subsequently assessed in 168 patients. For the initial 170 patients, the baseline INR (2.47±0.31 versus 1.53±0.31) and ACT (185±26 versus 153±30 seconds) were significantly greater in G≥2 (P<0.001). The amount of UFH to achieve the first ACT ≥300 seconds was significantly higher for G<2 versus G≥2 (9701±2390 versus 8268±2366 U; P=0.0001). Baseline INR, ACT, and weight were predictors of the UFH dosage to achieve an ACT ≥300 seconds. An equation derived to achieve an ACT ≥300 seconds after a single bolus of UFH met this end point in 160 of 168 patients (95%). Conclusions-Baseline INR and ACT, in addition to weight, are the only predictors of UFH dosage needed to achieve an ACT ≥300 seconds. A derived equation predicted the UFH dosage to achieve an ACT ≥300 seconds.

Original languageEnglish (US)
Pages (from-to)491-496
Number of pages6
JournalCirculation: Arrhythmia and Electrophysiology
Volume6
Issue number3
DOIs
StatePublished - Jun 2013
Externally publishedYes

Keywords

  • Anticoagulants
  • Atrial fibrillation
  • Catheter ablation
  • Heparin
  • Warfarin

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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    Hamam, I., Daoud, E. G., Zhang, J., Kalbfleisch, S. J., Augostini, R., Winner, M., Tsai, S., Rhodes, T. E., Houmsse, M., Liu, Z., Love, C. J., Tyler, J., Sachdev, M., Weiss, R., & Hummel, J. D. (2013). Impact of international normalized ratio and activated clotting time on unfractionated heparin dosing during ablation of atrial fibrillation. Circulation: Arrhythmia and Electrophysiology, 6(3), 491-496. https://doi.org/10.1161/CIRCEP.113.979088