Interpretation of Cardioversion Guidelines

Guidelines on oral anticoagulation (warfarin) – cardioversion

In the UK, it is common practice tomeasure a patient’s INR on the day of cardioversion and postpone the procedureif it is less than 2.0. The cancellation rate of cardioversion procedures canbe as high as 25% as a result. This causes a particular problem for patientsmanaged in the community if, on the day of the procedure, they are tested bythe laboratory using a different method to that used in the community.

The BCSH ‘Guidelines onoral anticoagulation (warfarin): third edition – 2005 update’ recognise thisproblem.  The guidelines recommend ‘a target INR of 2.5 for three weeks before andfour weeks after cardioversion’, but go on to say that a higher target INR(2.5 - 3.0) can be used prior to the procedure to minimise cardioversioncancellations due to low INRs on the day of the procedure. ‘Increasing the INR to 3.0 might reduce thestroke rate slightly and it is unlikely that this benefit would be offset by anincreased incidence of bleeding over a short period of time’.

Reference:Guidelines on oral anticoagulation (warfarin): third edition – 2005update.  T. P. Baglin, D. M. Keeling andH. G. Watson for the British Committee for Standards in Haematology.  British Society for Haematology, 132,277-285.