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SummaryThe effect of concomitantly administered clopidogrel on anticoagulation status was investigated in patients receiving long-term warfarin therapy. Forty-three patients with non-valvular atrial fibrillation who were receiving long-term warfarin and had a stable international normalized ratio (INR) between 2 and 3 were randomly assigned to clopidogrel 75 mg daily or placebo for 8 days (Days 1–8). INR (primary endpoint) and plasma levels of warfarin enantiomers (secondary endpoint) were evaluated at Days 3, 6, 9, 13 and 22. Mean INR remained extremely stable in the clopidogrel group, the maximum percentage change from baseline being 0.6% at Day 6. Plasma levels of R- and S-warfarin also remained very stable in those receiving clopidogrel. No serious adverse events, premature discontinuations of study drug or bleeding occurred with clopidogrel. In conclusion, the stable anticoagulation status of patients receiving long-term warfarin therapy is unaffected by concomitant administration of clopidogrel 75 mg daily.

Tal Horer, MD; Marten Vidlund, MD; Peter Lindell, MD; Kjell Jansson, MD, PhD Orebro University Hospital, Department of General Surgery (Horer, Jansson), Sweden; Orebro University Hospital, Department of Thorax Surgery (Vidlund), Sweden; Orebro University Hospital, Department of Cardiology (Lindell), Sweden Address for correspondence: Tal Horer, MD Department of general surgery Orebro University Hospital Sweden talherer@yahoo.com

Background The appropriate evaluation of atrial electrical function is only possible by means of invasive electrophysiology techniques, which are expensive and therefore not suitable for widespread use. Mechanical atrial function is mainly determined from atrial volumes and volume-derived indices that are load-dependent, time-consuming and difficult to reproduce because they are observer-dependent. Aims To assess the feasibility of tissue velocity echocardiography (TVE) to evaluate atrial electromechanical function in young, healthy volunteers. Subjects and methods We studied 37 healthy individuals: 28 men and nine women with a mean age of 29 years (range 20–47). Standard two-dimensional (2-D) and Doppler echocardiograms with superimposed TVE images were performed. Standard echocardiographic images were digitized during three consecutive cardiac cycles in cine-loop format for off-line analysis. Several indices of regional atrial electrical and mechanical function were derived from both 2-D and TVE modalities. Results Some TVE-derived variables indirectly reflected the atrial electrical activation that follows the known activation process as revealed by invasive electrophysiology. Regionally, the atrium shows an upward movement of its walls at the region near the atrio-ventricular ring with a reduction of this movement towards the upper levels of the atrial walls. The atrial mechanical function as assessed by several TVE-derived indices was quite similar in all left atrium (LA) walls. However, all such indices were higher in the right (RA) than the LA. There were no correlations between the 2-D- and TVE-derived variables expressing atrial mechanical function. Values of measurement error and repeatability were good for atrial mechanical function, but only acceptable for atrial electrical function. Conclusion TVE may provide a simple, easy to obtain, reproducible, repeatable and potentially clinically useful tool for quantifying atrial electromechanical function.