Effective anticoagulation eliminates thromboembolism following direct current cardioversion

M. M. Gallagher, B. J. Hennessy, N. Edvardsson, C. M. Hart, M. S. Shannon, O. A. Obel, N. M. Al-Saady, A. J. Camm

Research output: Contribution to journalArticle

Abstract

Background: Direct current cardioversion (DCC) of atrial fibrillation (AF) is carries a risk of thromboembolism that is reduced but not eliminated by anticoagulation. The risk of embolism after DCC of atrial flutter or atrial tachycardia is believed to be lower. No series to date has included enough patients receiving anticoagulants or enough with atrial flutter to estimate the risk of complication in either group. Methods: Review of the case records of 1950 patients who underwent attempted DCC on a total of 2639 occasions between 1990 and 1997. Results: DCC was preceded by warfarin therapy for at least 3 weeks in 1932 cases. No embolic complication occurred in 780 attempts performed with an INR of ≥ 2.5. In 756 cases the INR was < 2.5 and in 396 it was not measured on the day of DCC. Of these, 9 were complicated by cerebral lower limb embolism. Embolism was significantly more common at an INR of 1.5-2.4 than at an INR ≥ 2.5 (0.93% vs. 0%, p = 0.012, Fischer's Exact Test). DCC was performed within 2 days of the apparent onset of the arrhythmia in 443 cases, 352 without prolonged anticoagulation with 1 embolic complication. The overall incidence of embolism after DCC of atrial flutter or tachycardia was higher than after DCC for AF (0.72% vs 0.46%, p = ns). Conclusion: INR should be ≥ 2.5 at the time of DCC if the duration of AF is uncertain or > 2 days. The risk of embolism after DCC of atrial flutter is similar to that after conversion of AF so the same anticoagulation practices should be observed.

Original languageEnglish (US)
Pages (from-to)P5
JournalHeart
Volume81
Issue numberSUPPL. 1
StatePublished - May 1 1999

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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    Gallagher, M. M., Hennessy, B. J., Edvardsson, N., Hart, C. M., Shannon, M. S., Obel, O. A., Al-Saady, N. M., & Camm, A. J. (1999). Effective anticoagulation eliminates thromboembolism following direct current cardioversion. Heart, 81(SUPPL. 1), P5.