Kakar et al patients undergoing non-cardiothoracic surgery, the treatment should be similar to that of acute AF. Failed medical treatment, pre-excitation syndromes, poorly controlled symptomatic are all indications for non- medical interventions in AF. Various treatments including PVI (Wazni et al 2005), pacemaker therapy (Levy et al 1999), arrhythmia surgery (Kawaguchi et al 1996), atrioventricular (AV) junction catheter ablation (Ueng et al 2001), and atrial deﬁbrillators (Ricci et al 2004) have variable beneﬁt in these patients. Of course, all interventions have inherent procedural risks. AV junction ablation mandates the implantation of a permanent pacing system. The complications of PVI are not insigniﬁcant and include pulmonary vein stenosis. Also, the incidence of recurrence of asymptomatic AF post procedures is unknown and raises the dilemma of adequate anticoagu- lation. The recent NICE guidelines have not given speciﬁc guidance regarding the use of these procedures. However, NICE acknowledges their increasing role in AF manage- ment. The reasons for referral for specialist intervention or continued drug use should be explained and discussed with the patient. Antithrombotic therapy in AF The principal aim of antithrombotic therapy in AF is the pre- vention of ischemic stroke and other thromboembolic events. In prevention of stroke, there is overwhelming evidence from randomized trials and systematic reviews to suggest beneﬁt of thromboprophylaxis in patients with AF (Lip et al 2005, Hart et al 1999). Compared with placebo, warfarin reduces the risk of ischemic stroke and systemic embolism by two-thirds (Hart et al 1999, Benavente et al 2003). When compared with antiplatelet therapy, adjusted-dose warfarin leads to a 36% relative risk reduction in ischemic stroke (Hart et al 1999). In contrast, aspirin results in a 22% risk reduction in prevent- ing ischemic stroke among patients with AF, compared with controls (Hart et al 1999). This result is largely driven by the Stroke Prevention in AF (SPAF-1) clinical trial, where aspirin was more effective in reducing non-disabling strokes but did not reduce severe or recurrent strokes in those aged 75 and over (SPAF study 1991). Anticoagulation for persistent AF depends on the adop- tion of either a rate-control or rhythm-control treatment strategy. Where a rhythm-control treatment strategy is chosen, antithrombotic therapy is needed to prevent acute stroke or other thromboembolic events occurring during or shortly after cardioversion. It is well accepted that patients should maintain therapeutic anticoagulation (INR 2.0–3.0) 112 with warfarin for a minimum of 3 weeks pre-cardioversion (Collins et al 1995; Klein et al 2001) and for a minimum of 4 weeks post cardioversion. In acute cases where cardiover- sion cannot be postponed, heparin should be administered, cardioversion performed, and warfarin be administered for at least four weeks post cardioversion. The use of trans- oesophageal echocardiography may help exclude a left atrial thrombus and thus facilitate acute cardioversion where adequate pre-procedure anticoagulation was not possible (Klein et al 2001). Data from the rate versus rhythm-control trials sug- gest that consideration should be given towards long-term anticoagulation in patients at high risk of stroke and AF recurrence. This is particularly important as there may be frequent asymptomatic AF recurrences that can lead to thromboembolism in the presence of risk factors (Wyse et al 2002; Corley et al 2004; Lim et al 2004). Among patients with permanent AF, adjusted-dose war- farin is again the most effective treatment aiming for a target international normalized ratio (INR) of 2.5 (range 2.0–3.0). Where warfarin is inappropriate, aspirin (EAFT 1993; Hart et al 1999; Lip et al 2005) should be administered at 75–300 mg/day. Aspirin should not be co-administered with warfarin as it provides no additional thromboprophylactic beneﬁt and may in fact be harmful (Lechat et al 2001). There is not enough evidence at the moment to recommend combination antiplatelet agents for AF. Of note, a recent large clinical trial found anticoagulation to be superior to aspirin-clopidogrel combination therapy for stroke prevention in AF (ACTIVE, Lancet 2005). The effectiveness of anticoagulation in reducing the rate of ischemic stroke is similar for patients with either parox- ysmal or permanent AF (Van walraven et al 2002). Patients with paroxysmal AF have an annual stroke rate similar to permanent AF (3.3%) (Lin et al 1996). Paroxysmal AF pa- tients also frequently have asymptomatic recurrences, and thus, they are exposed to the risk of recurrent AF without recognition. Anticoagulation for paroxysmal AF should not be based on the frequency or duration of paroxysms but on appropriate risk stratiﬁcation, as for permanent AF. The onset of AF is associated with a cluster of thrombo- embolic events (Wolf et al 1983), but the development of intra-atrial thrombi, and the immediate risk of thromboem- bolism, is perceived to be minimal within the ﬁrst 48 hours. Thus, in patients presenting with AF, a clear history of onset is necessary in order to guide appropriate antithrombotic therapy and cardioversion. Common clinical practice is that cardioversion may be safely performed without the need Vascular Health and Risk Management 2007:3(1)