Detecting Atrial Fibrillation in primary care

A paper published in the British Journal of General Practitioners (BJGP) on 22 May 2018 has identified that opportunistic pulse-checking by GPs in the over 65 year old age group increases detection of an abnormal heart rhythm called atrial fibrillation (AF).

The study, performed at Barts and the London School of Medicine, which involved GP practices in City and Hackney, Tower Hamlets and Newham, used computer prompts, templates and performance feedback to encourage and remind GPs to take pulses during routine consultations. The study was a retrospective analysis of electronic records in the above three Clinical Commissioning Groups (CCGs) over 10 years, with the pre-intervention period being from 2007-2011 and the post-intervention period from 2012-2017. It was noted that, across the three CCGs, rates of pulse regularity checks increased from a pre-intervention mean of 7.3% to a post-intervention mean of 66.4%, reaching a significant 93.1% in the final year (n=58,722). The prevalence of AF in the over 65 year olds increased from the pre-intervention level of 61.4/1000 to 64.5/1000 post-intervention, and 67.3/1000 in the final year, which was an improvement of 9.6%, with 790 new cases of AF identified.

This was a significant increase in detection of AF of almost 10% over 5 years, the equivalent of preventing 28 strokes. However, there is no evidence-based national screening programme for asymptomatic AF, or irregular heartbeat, in the over 65 year olds in the UK, which means that GPs are depended upon for detecting it opportunistically when patients attend for other reasons. However, this puts yet more pressure on GPs during what is often only a 5-10 minute consultation dealing with other matters, and a national screening programme with proper and robust protocols and procedures would likely be beneficial.

The detection and management of AF is a significant matter. AF is the commonest arrhythmia seen in medical practice, characterised by an ‘irregularly irregular’ pulse, and it is associated with an increase in morbidity and mortality. The prevalence of AF increases with age, from about 0.5% of those aged 50-59 to 8.8% of those aged 80-89. It is estimated that about 25% of patients with AF are undiagnosed. The risk of strokes from AF, in which it has been implicated in 15-30%, can be significantly reduced with anticoagulants (e.g. warfarin, although there are also more novel anticoagulants available), by about two-thirds. The management of AF is costly, as is the failure to prevent strokes caused by it.

However, it is necessary for AF, which is often asymptomatic, to be identified before an adverse event has occurred so as to avoid a catastrophic event resulting in long-term, and costly, disability. ECG is the gold-standard investigation, demonstrating a loss of ‘P’ waves, but it has been considered as too time-consuming and expensive to be used as a screening tool, so opportunistic ‘screening’ by GPs has been encouraged instead. Nevertheless, the paper in the BJGP shows that such an approach hitherto has not been overly successful without further measures being taken.

Notwithstanding that there is no national screening programme in place in the UK and accordingly that the NICE (National Institute for Health and Care Excellence) guidelines presently do not recommend manual pulse palpation routinely in asymptomatic patients[2], it is arguable that a failure by a GP at a routine appointment to detect, by simple manual palpation of the pulse, asymptomatic AF would now be considered to be unacceptable, and illogical, practice. GPs should, therefore, be pro-active in routinely taking their over-65 year old patients’ pulses, most importantly so as positively to identify, and if necessary treat, those patients with asymptomatic AF, but also so as to avoid any potential criticism in failing to do so.

With respect to management, NICE recommends that all patients at high risk of stroke should be offered anticoagulants. However, it seems that some GPs still believe that the antiplatelet, aspirin, is an effective alternative to warfarin and it is claimed that up to 25% of AF sufferers are still on antiplatelet monotherapy. This is unacceptable, as the BAFTA trial demonstrated that aspirin is half as effective at preventing strokes as warfarin whilst still increasing bleeding risk. The NICE guidance is (as from 2014) explicitly against the use of aspirin monotherapy in AF patients and, accordingly, its use is likely now to be considered unacceptable practice.

Further, even when anticoagulation is appropriately prescribed, the dose, and therefore the individual time in the therapeutic range (ITTR), is significantly reduced, reducing the clinical effectiveness. This is also an area of possible criticism and the aim is to make sure that the ITTR is >65% .

A very helpful guide can be found at stroke.org.uk, titled AF: How can we do better?, updated in 2018, and it is well worth reading. It is evident that there is still significant room for improvement in the primary care sector in the detection and management of asymptomatic AF, both so as to reduce the number of avoidable catastrophic strokes that occur on a regular basis and to prevent the associated costs of related long-term disability, and also to avoid subsequent criticism of the detection and management of AF and possible consequential legal action.

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