When a decision to interrupt warfarin therapy for an invasive procedure has been made for a patient with AF/AFL, we suggest that bridging therapy with LMWH or UFH be instituted when the INR is below that patient's therapeutic INR target in a patient at high risk of thromboembolic events (CHADS₂ ≥3, mechanical heart valve, stroke or TIA within three months, rheumatic heart disease) (Conditional Recommendation, Low Quality Evidence)