Understanding the risk factors of atrial fibrillation

Dr Angie Brown

Consultant Cardiologist and Medical Director, Irish Heart Foundation

Atrial fibrillation (AF) is the most common cardiac arrhythmia, affecting one in four people over 50 years old. With AF the heart rate becomes completely irregular.

Although some people complain of palpitations, dizziness, breathlessness or chest tightness, 70% of AF is asymptomatic or ‘silent’. This means the actual true prevalence in the community is unknown and probably underestimated.

Data collected from pacemakers, loop recorders and Holter monitors show that even short episodes of AF (less than one hour) convey an increased risk of stroke. The difficulty in diagnosing such cases can be improved by screening with regular pulse checks, more prolonged monitoring, or loop recorder insertion.

Risk factors for atrial fibrillation

The risk of developing atrial fibrillation increases with age. Prevalence is also increasing due to better survival post myocardial infarction (MI), congenital and valvular heart disease, and increasing hypertension and obesity. Other recognised risks are viral infections, pneumonia, heart failure, lung disease, diabetes, sleep apnoea, thyroid disease and lifestyle factors such as excess alcohol, coffee and cigarettes.

The difficulty in diagnosing such cases can be improved by screening with regular pulse checks, more prolonged monitoring, or loop recorder insertion.

Overweight populations have a higher AF incidence and progression of AF compared with normal weight counterparts. Obese patients with atrial fibrillation who lose at least 10% of their body weight are six times more likely to achieve long-term freedom from AF compared to those who don’t lose weight.

Finding the right treatment

Treatment includes ensuring there are no potentially reversible causes such as thyroid disease and excess alcohol. Good blood pressure control and weight loss in obese patients reduces the risk of recurrent AF. In some studies, statin therapy appears to reduce AF and in other studies beta-blocker use in heart failure also reduces the risk of AF.

AF significantly increases the risk of stroke so prevention of stroke with anticoagulants (blood thinners), if appropriate, is crucial. In some patients we would consider restoration of sinus rhythm with medication, ablation or cardioversion. In others it’s important to ensure adequate rate control with a variety of medications. The treatment options will vary depending on patient factors and symptoms.