[Anticoagulation in patients with atrial fibrillation].
Nonvalvular atrial fibrillation is a frequent finding in elderly patients; the risk of thromboembolic complications is comparable to that reported in patients with rheumatic atrial fibrillation. Recently, 6 multicenter clinical trials (5 primary prevention, 1 secondary prevention trail) have been published which demonstrate equivocally that oral anticoagulation therapy significantly reduces the embolic risk in patients with nonvalvular atrial fibrillation by about 67% to 87%. The target INR of anticoagulation with warfarin in 2 of these trials was 1.4 to 2.8 ("low-dose" warfarin); interestingly, the magnitude of risk reduction was similar to these 2 studies with "low-dose" warfarin as it has been reported by the others using full-dose warfarin with an INR target between 2.0 and 4.5. Side effects of oral anticoagulation (severe bleeding complications) were low in these trials. Thus, the benefit-risk ratio in these 6 clinical trials encourage the use of oral anticoagulation in patients with nonvalvular atrial fibrillation. It will be a challenge to transfer these results to clinical practice, and to define in more detail the risk-benefit ratios for subgroups of patients with atrial fibrillation, e.g. patients > 75 years of age, or patients with "lone" or paroxysmal atrial fibrillation. It is well established that patients with chronic atrial fibrillation undergoing medical or DC-cardioversion are at risk for thromboembolic complications. In previous studies, this risk appears to be in the range of 2% without concomitant anticoagulation, but only 0.33% in those patients with concomitant anticoagulation. Thus, it is widely accepted that patients should be anticoagulated for at least 2 weeks prior and after planned cardioversion. Recently, an alternative concept has been proposed omitting anticoagulation before cardioversion; instead, transesophageal echocardiography is used to exclude intracardiac thrombi. Because it is known that mechanical function of the left atrium and appendage is still impaired after cardioversion, this concept of echocardiographic-guided cardioversion does not assign the necessity of anticoagulation at the day of cardioversion, and 2 weeks afterwards. The safety aspects of this concept of echocardiographic-guided cardioversion is under current investigation.
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Abteilung für Kardiologie, Medizinische Hochschule Hannover.
D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000097:blood / Q000150:complications* / Q000209:etiology; D017147:Defibrillators, Implantable; D004305:Dose-Response Relationship, Drug; D006801:Humans; D015337:Multicenter Studies as Topic; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D013923:Thromboembolism / Q000097:blood / Q000188:drug therapy*; D014859:Warfarin / Q000009:adverse effects / Q000627:therapeutic use
D000925:Anticoagulants; D014859:Warfarin
Antikoagulation bei Patienten mit Vorhofflimmern.