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tissue , perhaps mediating part of the increased risk of AF in obese individuals . 38 There is RCT evidence that weight loss programs in patients with AF reduce both the amount of AF experienced as well as AF symptom burden . 14

Obesity not only independently predicts the incidence of AF , it also has a complex interplay with OSA , which is also independently associated with an increased incidence and burden of AF . OSA is thought to damage the atria by a host of mechanisms , including intermittent nocturnal hypoxia and hypercapnia , oxidative stress and neurohumoral activation . 39 Untreated OSA reduces the success rates of pharmacological and invasive rhythm control , with CPAP improving the rate of successful rhythm control in these patients . 40 For this reason , it is reasonable to screen for OSA when pursuing rhythm control , or in those with symptomatic AF .

ALCOHOL INTAKE Alcohol intake , even at moderate levels ( for example , 7-14 drinks per week ) increases the risk of AF , with greater intake corresponding to a still higher risk . 41 Excessive alcohol intake also increases the risk of bleeding in those on anticoagulant therapy for AF . 42 A recent Australian RCT has shown that alcohol abstinence in those with known AF who regularly drink more than 10 standard drinks per week almost halves the rate of recurrence of AF . 21 Conversely , there is no evidence of a negative association

1 . Which THREE cardiovascular conditions are most commonly linked to the increased risk of death in patients with AF ? a Stroke . b CAD . c Aortic dissection . d Congestive cardiac failure .

2 . Which TWO statements regarding the epidemiology of AF are correct ? a About half of those with a first presentation of AF have an identifiable precipitant . b AF is more common in the younger population , declining after the age of 65 . c AF is more prevalent among Aboriginal and Torres Strait Islander peoples . d The prevalence of AF is expected to double over the next 20 years because of an ageing population , increased prevalence of contributory disease and better detection .

3 . Which THREE statements regarding AF are correct ? a AF results in regular , and often very frequent , electrical conduction to the ventricles . b AF is self-perpetuating . c The stagnant blood flow that results from the absence of

Figure 9 . Left atrial appendage closure .

between caffeine consumption and AF , although caffeine consumption can , like AF , cause unpleasant palpitations . 43

EXERCISE Exercise reduces the risk of cardiovascular mortality , and can reduce

synchronised contraction predisposes the patient to clots . d AF is thought to result from abnormal atrial substrate that is the result of injury and / or fibrosis in the atria .

4 . Which THREE are appropriate in the diagnosis and management of AF ? a A 12-lead ECG . b Transthoracic echocardiogram . c Regular opportunistic screening for all patients over the age of 65 . d Routine screening for CAD in patients with AF .

5 . Which ONE statement is NOT a key principle in the management of AF ? a Choice and enactment of rate or rhythm control . b Prevention of stroke . c Vigorous endurance exercise . d Management of risk factors .

6 . Which TWO statements regarding the management of AF are correct ?

AF burden through its effects on weight loss . 44 However , there is a paradoxically increased prevalence of AF among those who participate in vigorous endurance sports , such as marathons and long-distance triathlons . The enlarged atria found disproportionately among athletes

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a Most patients with AF are haemodynamically unstable . b A rhythm control strategy involves attempting to convert the patient to sinus rhythm and to maintain this rhythm . c A rate control strategy attempts to bring the heart rate down to an acceptable target range which is less likely to cause symptoms or ventricular dysfunction . d Combination oral beta blockers and nondihydropyridine CCBs are first-line agents .

7 . Which THREE statements regarding the pharmacotherapy for rate and rhythm control in AF are correct ? a Non-dihydropyridine CCBs may cause postural hypotension . b Flecainide is safe in those with a history of MI . c Digoxin can be used as a standalone or in combination with either a beta blocker or non-dihydropyridine CCB .

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ATRIAL FIBRILLATION

may mediate some of this increased risk . 45 Nevertheless , given the overwhelming health benefits of exercise , it is reasonable to continue vigorous exercise in the absence of symptomatic AF that causes distress to the patient .

HYPERTENSION Hypertension is thought to increase the risk of AF through its harmful effects on atrial remodelling ; this is the most common aetiological factor found in AF . 46 Hypertension increases the risk of AF , increases the risk of stroke in those with AF and increases bleeding risk for those on anticoagulation . Good blood pressure control is therefore essential in the prevention and management of AF . 47

CASE STUDIES

Case study one

JAMES , 67 , who is asymptomatic and obese , presents for a regular check-up . He has a history of well-controlled dyslipidaemia and hypertension . Pulse palpation reveals an irregularly irregular rhythm of 102bpm , increasing to 126bpm on minimal exertion . His blood pressure is 128 / 75mmHg . An ECG confirms irregular QRS complexes and no discernible P waves , and a diagnosis of AF is made . His

CHA 2

DS 2

-VA score is calculated to be 2 ( points for age and hypertension ). Biochemistry reveals normal renal function , electrolytes , and thyroid function tests . A transthoracic echocardiogram reveals no evidence of structural heart disease

d Both amiodarone and sotalol may cause a prolonged QTc .

8 . Which TWO statements regarding the management of AF are correct ? a Those with non-valvular AF have a higher risk of ischaemic stroke than their valvular counterparts . b Anticoagulation is recommended in those with a CHA 2

DS 2

-VA score of 2 or greater . c NOACs are the anticoagulant of choice for those with valvular AF . d Warfarin is the anticoagulant of choice for those with valvular AF .

9 . Which THREE criteria are used when NOAC dose reduction is required in AF ? a Age . b Other drugs being used . c Bleeding risk . d Gender .

10 . Which THREE are key risk factors in the management of AF ? a Obesity . b Caffeine intake . c OSA . d Hypertension . or prior rheumatic heart disease .

He is prescribed metoprolol 25mg bd for rate control , and apixaban 5mg bd for stroke prophylaxis after appropriate education and counselling . On further history , James acknowledges his partner often complains about his snoring , and he frequently falls asleep while watching television . James is counselled on weight loss and referred for a sleep study to screen for OSA .

Case study two

Mary is a 55-year-old Indigenous woman . She presents with concerns regarding daily intermittent palpitations for the past two months . Mary is otherwise well .

Her 12 lead ECG at the time of review reveals sinus rhythm with a QTc of 423ms ( normal range is 360 to 460ms for adult women ). A 24-hour Holter monitor is requested , which reports intermittent AF corresponding to the timing of her symptoms . Mary ’ s

CHA 2

DS 2

-VA score is calculated to be 0 : however , a transthoracic echocardiogram reveals mild rheumatic mitral stenosis and moderate left atrial dilation .

On further questioning , Mary reports no known personal history of rheumatic heart disease but knows one sibling and several cousins were affected by the disease in childhood . Mary is counselled on the risk of stroke , and prescribed warfarin for her valvular AF after appropriate education , aiming for an INR of 2.0-3.0 . She is also prescribed sotalol 40mg bd for rhythm control to improve her symptoms . She undergoes a 12-lead ECG one week after starting sotalol to check for dangerous QTc prolongation .

CONCLUSION

AF is the most common cardiac arrhythmia . Appropriate management is key to preventing its devastating potential sequelae , such as stroke and heart failure . The treatment approach is three-pronged . The first focus is stroke prevention with appropriate anticoagulation if indicated . The second is adequate rate or rhythm control to alleviate symptoms and prevent heart failure . And the third is management of associated risk factors . This article has aimed to update GPs on the screening , diagnosis , and initial management of AF , as well as their crucial role in the screening and management of risk factors such as hypertension , OSA , obesity and alcohol intake .

RESOURCES

• Hindricks G et al 2020 European Society of Cardiology guidelines for the diagnosis and management of atrial fibrillation . European Heart Journal 2021 ; 42:373-498 bit . ly / 3uPtG7U

• Brieger D et al National Heart Foundation of Australia and the Cardiac Society of Australia and New Zealand : Australian clinical guidelines for the diagnosis and management of atrial fibrillation 2018 . Heart , Lung and Circulation 2018 ; 27:1209-1266 bit . ly / 2O91upf

References Available on request from howtotreat @ adg . com . au