Top Tips: Common Mechanisms in Heart Failure and Atrial Fibrillation

Professor Gregory Lip Provides 10 Top Tips for Cardiologists on the Management of Atrial Fibrillation and Heart Failure, Encompassing the Latest Guidelines and Trial Evidence

Introduction

Both atrial fibrillation (AF) and heart failure (HF) are commonly occurring conditions with many shared aetiological risk factors that are pathophysiologically inter-related.¹ On a population basis, hypertension and ischaemic heart disease are the most prevalent predisposing risk factors for both.¹ Other increasingly common risk factors include diabetes, valvular heart disease, obesity, and sleep apnoea.¹ In addition, the prevalence of both AF and HF increases with age, adding to multimorbidity and frailty and leading to a higher risk of adverse outcomes in these clinically complex patients.^2–5 In patients who have HF with preserved ejection fraction (HFpEF), increased atrial stretch and intra-atrial pressures can also lead to AF.^4,5

Patients who have AF commonly present with HF, and patients who have HF may develop AF;¹ approximately one-third of those who have HF also have AF.^1,6 The presence of both conditions is additive to the risks of mortality and morbidity.¹

This article provides 10 top tips on the optimal management of these conditions occurring either alone or in combination.

1. Prevent Progression to Atrial Fibrillation in Patients with Heart Failure, and Vice Versa

Preventing progression from HF to AF requires attention to all comorbidities and ensuring optimised medical treatment for HF. Increasingly, data show that the pillars of HF management result in a lower risk of incident AF among patients who have HF with reduced ejection fraction (HFrEF). These are:^1,7,8

• angiotension-converting enzyme inhibitors (ACE-Is)/angiotension receptor blockers (ARBs)
• mineralocorticoid receptor antagonists (MRAs) spironolactone or eplerenone
• sodium–glucose co-transporter-2 inhibitors (SGLT-2is)^9–12—although the jury is still out with regard to their role in AF prevention.

Preventing progression from AF to HF also requires proactive management of comorbidities, including blood pressure control, sleep apnoea management, and attention to cardiac ischaemia.^1,6

2. Use Cardiac Imaging to Establish the Full Picture in Heart Failure

Ideally, HF is diagnosed from clinical history and examination, and appropriate cardiac imaging.⁸ An electrocardiogram (ECG) may provide clues from the presence of left ventricular (LV) hypertrophy—for example, due to hypertension—or show a prior myocardial infarction or ischaemia.⁸ Blood tests should include the assessment of renal function, and primary care physicians often test for N-terminal pro-B-type natriuretic peptide (NT–proBNP) as a ‘rule out’ biomarker for HF.⁸ However, these biomarkers can be non-specific, and may be altered by renal impairment, underlying arrhythmias, infection, or other factors.⁸

Echocardiography can help to differentiate between HFrEF, HFpEF, and—as specified in the latest European Society of Cardiology guidelines—HF with mildly reduced ejection fraction (HFmrEF).^7,8 It can also be used to assess associated valvular heart disease. Other imaging modalities, such as cardiac magnetic resonance imaging (MRI), can help in the diagnosis of cardiomyopathies and infiltrative disease that may lead to a patient presenting with HF. Underlying cardiac ischaemia and viability can be identified via perfusion MRI, especially when HFrEF is due to cardiac ‘stunning’ from chronic ischaemia.⁸

3. Assess Risk of Stroke and Thromboembolism in Patients with Atrial Fibrillation

AF is associated with a high mortality and morbidity from stroke and thromboembolism.¹³ The risk is not homogeneous, and is dependent upon associated stroke risk factors;^13,14 the most common and validated of these have been used to formulate stroke risk stratification scores, with the CHA₂DS₂-VASc score used most frequently globally.^13,15 Within this, ‘C’ refers to congestive heart failure, defined as recent decompensation (usually presenting to clinic or hospital) with HF or, even if asymptomatic, the presence of moderate-to-severe LV dysfunction on cardiac imaging.^6,14 However, this risk is not static, and alters with ageing and incident comorbidities.⁶

4. Optimise Pharmacotherapy for Patients with Heart Failure and Atrial Fibrillation

When managing HFrEF, the four pillars of drug therapy are: ACE-Is/ARBs, MRAs, beta-blockers, and SGLT-2is.⁸ All four have shown prognostic benefit in patients with HF. If HF occurs in association with AF, the use of beta-blockers helps in heart rate control, but may not confer a prognostic mortality benefit.¹⁶ Some of the data for ACE-Is/ARBs, MRAs, and possibly SGLT-2is suggest a reduction in incident AF.^1,9–12

Current guidelines recommend the use of SGLT-2is for the management of HFpEF based on their prognostic benefit, as demonstrated in large, randomised trials.⁷ Risk factor management still applies.

5. Consider Cardiac Resynchronisation Therapy for Some Heart Failure Patients

The use of cardiac resynchronisation therapy is associated with an improvement in cardiac haemodynamics in HFrEF, and improved outcomes in patients in sinus rhythm.⁸ When AF is present, there is some evidence of benefit, although this is perhaps less marked than for patients in sinus rhythm.⁸ In severe LV dysfunction, an implantable cardioverter defibrillator may be beneficial in reducing the risk of sudden cardiac death due to ventricular arrhythmias.⁸

6. Use the ABC Pathway for Patients with Atrial Fibrillation

In AF patients with associated HF, a holistic or integrated care approach to management based on the Atrial fibrillation Better Care (ABC) pathway is recommended (Box 1).^6,17,18

Adhering to the ABC pathway has been associated with a reduction in all-cause mortality, cardiovascular mortality, stroke, and bleeding.²³ The mAFA trial, a prospective study of the ABC pathway,²² found that the composite primary endpoint of stroke/thromboembolism, death, and hospitalisations was reduced by two-thirds. It has also been shown to be cost-effective; the largest driver of healthcare costs in AF is hospitalisations, and the ABC pathway has the potential to reduce these over the long term.²⁴ Indeed, in the heart failure subgroup of the mAFA-II trial, the primary outcome was also significantly reduced compared to usual care by using the ABC pathway.²⁵

This compelling evidence base has led to the ABC pathway being recommended in guidelines from the USA, Europe, and the Asia–Pacific.^6,18,26

7. Consider Early Rhythm Control

Recent studies suggest early rhythm control is beneficial in selected patients, and can even reduce the risk of stroke, although HF outcomes were less impacted. In the CASTLE-AF trial, catheter ablation resulted in an improvement in clinical outcomes in patients with AF and HF.²⁷ In the more recent CASTLE-HTx trial in patients who have AF and end-stage HF, catheter ablation with guideline-directed medical therapy was associated with a lower likelihood of death, urgent heart transplantation, or implantation of an LV assist device than medical therapy alone.²⁸

8. Assess Bleeding Risk when Starting Anticoagulants

When initiating oral anticoagulants (OACs), bleeding risk should be assessed. Bleeding risk is dependent upon modifiable and non-modifiable bleeding risk factors, and various bleeding risk scores have been proposed.²⁹ These scores should be used to identify modifiable bleeding risk factors for mitigation, and to flag up patients at high bleeding risk for early review and follow up.²⁹ The HAS–BLED score³⁰ is the most validated clinical risk score, and was shown in the mAFA-II trial to be associated with a lower rate of major bleeding, as well as an improved uptake of OACs compared to usual care.³¹

9. Address Comorbidities

Attention to comorbidities is essential in the management of patients who have AF, and includes blood pressure control (optimal blood pressure 120–129/<80 mmHg), treating sleep apnoea, weight reduction, reducing alcohol intake, and smoking cessation.⁶ Healthy lifestyle factors (smoking cessation, reduction of alcohol, and physical activity) have been associated with less incident AF and AF-related complications.^32,33

10. Prevent Further Complications Such as Stroke, Dementia, and Heart Failure Hospitalisation

Both AF and HF are associated with stroke and thromboembolism, and the concomitant presence of both is additive to stroke risk. OACs are clearly associated with a reduction in stroke/systemic embolism in AF compared to placebo or control.³⁴ In patients who have HF, clinical trials did not show a reduction in mortality or HF hospitalisation with the use of OACs, and was offset by an increase in bleeding, especially when used in combination with antiplatelets.^35,36 Nonetheless, the secondary outcome of stroke was reduced with OACs compared to antiplatelets.

AF and HF are both associated with cognitive decline.^37–40 Indeed, AF has been shown to be associated with incident dementia, both Alzheimer’s and vascular dementia.⁴⁰ This is worsened by poor lifestyle factors, such as smoking and excess alcohol.⁴¹ Adherence to the ABC pathway has been associated with a lower risk of incident dementia in patients with AF.⁴²

The development of AF may account for acute presentations with HF decompensation, given that AF often develops asymptomatically, and may only become obvious when the haemodynamic compromise is such that patients develop pulmonary oedema, requiring either hospital attendance or hospitalisation.⁴³ 

Given the major impact of the ABC pathway on hospitalisations, it is recommended that implementation and adherence to the ABC pathway in AF patients with HF be promoted.^{6,17,18,22–25} The associated reduction in strokes and bleeds of using a streamlined approach such as the ABC pathway equates to substantial healthcare cost reductions and lives saved.⁴⁴

Conclusion

Current guidelines recommend a comprehensive approach to AF management that also applies in the presence of associated HF.^6,18 A holistic approach based upon the evidence-based ABC pathway is associated with improved clinical outcomes.²³

The importance of comorbidity and cardiovascular risk factor management cannot be overemphasised. When AF is present, OACs are recommended for stroke prevention, with a preference for direct oral anticoagulants. In selected patients with AF and HF, early rhythm control may be beneficial. Given that risk does not remain static and is dynamic, regular re-assessment is recommended, especially as risk alters with ageing and incident comorbidities.^45,46