By Associate Professor Kushwin Rajamani, Cardiologist and Cardiac Electrophysiologist, Nedlands
The incidence of atrial fibrillation (AF) in Australia is among the highest in the world. Atrial fibrillation has major implications with a five-fold increase in heart failure and two-fold increase in cardiovascular death.
Across Australia, AF related hospital admission is now the most common cause of cardiovascular hospitalisation, contributing up to a five-fold increase in stroke risk and responsible for 20% of stroke incidence.
The economic impact of atrial fibrillation annually is $1.25 billion and for stroke it is more than $15 billion. These are astounding figures both clinically and economically, creating a national emergency for early detection, intervention and treatment.
Current research
Advancing research is key to developing targeted treatment modalities. In vitro models using 3-dimensional engineered tissue models of varying cell types such as fibroblasts, endothelial cells, neurons and immune cells could offer a more realistic assessment of the microenvironment related to arrhythmogenicity.
The use of animal models has provided critical knowledge about mechanism, substrate and molecular differences. Certain gaps including the biological pathways that lead to the atrial triggers and substrate, mechanism of atrial remodelling and clot formation, sex differences and outcomes based on comorbidities are to be determined.
Gene testing or genotyping at this stage is largely undertaken in research settings and there is potential for early detection of AF risk and early preventive strategies with pre-emptive genotyping.
The underlying pathophysiologic mechanism that results in the onset, maintenance and progression of atrial fibrillation can be classified into ‘triggers’ and ‘substrate’. Triggers are fundamentally referred to as the electrical ectopic activity from the pulmonary veins and substrate pertains to the structural remodelling of the atrium characterised by fibrosis, fatty infiltration, and inflammation leading to conduction abnormalities and re-entry resulting in AF.
Key messages
- Atrial fibrillation is an important healthcare priority with increasing burden.
- Primary prevention is the key.
- Addressing atrial fibrillation requires a collaborative effort with engagement of the public, healthcare providers, researchers, industry, government, policy makers, patient advocates and campaigners.
New technologies
The prospect of machine learning using ECG data including P wave duration, amplitude and dispersion, along with electrical biomarkers may hold promise for prediction of AF. The value of atrial imaging specifically using cardiac MRI to quantify fibrosis need to be evaluated further to be considered as a measure to guide therapy.
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There have been significant advancements in the options for rhythm control over the past three decades. Catheter ablation for AF is now considered a Class IA recommendation in clinical guidelines to reduce the risk of recurrence of atrial fibrillation and symptoms.
Radiofrequency ablation has been the mainstay thus far and, to a lesser extent, cryoablation. There is rapidly emerging use of Pulse Field Ablation technology to achieve pulmonary vein isolation. AF ablation is more effective than anti-arrhythmic therapy, however, there remains a high burden of recurrent AF after PVI.
This leads to the focus on aggressive lifestyle modifications and addressing biological mechanisms that contribute to AF.
There is strong evidence that lifestyle changes alone can influence the incidence, maintenance and progression of AF. Australian-led research has proven that weight loss with aggressive risk factor reduction, exercise training, management of sleep apnoea and alcohol abstinence can result in reduction in AF burden and symptoms.
Primary prevention
Primary prevention is key. Developing improved risk scores employing polygenic risk assessment tools, electrical or blood-based biomarkers and cardiac imaging indicators may allow for targeted intervention for high-risk individuals.
The value of managing hypertension, diabetes, obesity and physical inactivity in reducing AF cannot be underestimated. The advent of AI driven tools may accelerate the ability to identify high-risk individuals across various demographics allowing for education, risk factor reduction, early identification and treatment.
Population based screening may help detect AF early to reduce the progression of AF, hospital admissions and perhaps the prevention of stroke.
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Patient education and empowerment is a key priority to achieve self-management, compliance, reduction in hospital admissions and improved quality of life. Education programs need to enhance the understanding of AF, the symptoms, management, compliance to therapy and possible complications. These initiatives would particularly assist asymptomatic patients to take the condition more seriously.
Shared decision making with a patient-centric approach allows patients to actively participate in their care.
The technological advancements with smart watches and self-monitoring tools provide real time data and help patients to monitor their own heart rate and trends so they can be empowered to participate in the process.
Support groups, online communities and phone applications could provide useful information, shared experiences and offer emotional support.
Health information integration between hospitals, primary care physicians and cardiologists will certainly optimise the delivery of care and improve outcomes. Both rural and indigenous populations who tend to have worse outcomes will additionally benefit from all these initiatives.
Author competing interests – nil
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