Anticoagulation

There have been detailed reviews of anticoagulation for AF and, since these, no new end-point guidelines or new therapeutic agents have been introduced in the US. As noted previously, however, what has become apparent is that many, if not most, patients have recurrent episodes of AF that go unrecognized.As such, there remains a risk of thromboembolism if anticoagulation is discontinued without thorough documentation of perfect (or near-perfect) control of sinus rhythm. It is the presence of AF, not its symptoms, that determines the existence of embolic risk.

Experts therefore currently recommend that anticoagulation, once initiated, be continued indefinitely in a patient with AF unless, or until it is certain that, recurrences are either absent or can reliably be recognized during the first day that they recur so that anticoagulation can be immediately reinstituted, and it is clear that episodes are infrequent and always too brief to be of clinical importance. Accordingly, warfarin should only be discontinued in patients whose prompt and correct recognition of episodes has been repeatedly documented and in whom self checking of the pulse twice a day has become a regular part of their health routine, wherein they contact their physician as soon as a persistently irregular pulse is noted.

Fortunately, in the near future,warfarin use is likely to be replaced in most patients with the exciting class of agents now under development known as oral thrombin inhibitors. Furthest along appears to be the drug known as ximelagatran (Exanta, AstraZeneca).

Ximelagatran is being studied in the therapy of venous thrombosis, the prevention of venous thrombosis and pulmonary embolism, and the therapy of AF; it is being compared with standard anticoagulant regimens in these situations.(8,9) Ximelagatran is an oral agent that is given in the same dose in all subjects, has a short half-life (allowing it to reach therapeutic levels in a day), has no drug or food interactions, and requires no anticoagulant blood test monitoring during its use. It appears likely (though not definite) that this agent will be added to the clinical armamentarium by the middle of this decade.

Sinus Rhythm Control

The fourth of the issues to consider during the approach to AF, as noted previously, is the issue of sinus rhythm control – whether or not to pursue the restoration and maintenance of sinus rhythm or leave the patient in AF and, if sinus rhythm is to be pursued, how best to help maintain it.

There are only two general reasons to treat patients with any disorder – to make them feel better and/or to make them live longer.As previously noted, for patients with AF who are symptomatic despite ventricular rate control, sinus rhythm should become the target of therapy, and the choice of which AAD(s) to select and which to avoid has clearly become defined by the algorithmic approach published in the American College of Cardiology (ACC), American Heart Association (AHA), European Society of Cardiology (ESC), Association of School Psychologists (NASPE) and other similar internationally developed guidelines.(3) In this arena, however, investigational antiarrhythmic drugs are under development that offer the promise of more convenient dosing, lower toxicity, fewer drug interactions, and/or better tolerance.