Atrial fibrillation: hidden heart condition for over 40s
28 November 2011
At least 50,000 Australians aged 40 years or older may have atrial fibrillation (AF) - a disorder of heart rhythm that increases the risk of stroke - without knowing it, new data suggest.
In AF, the electrical signals that control your heartbeat are abnormal and cause the upper chambers of your heart (the atria) to beat so fast that the lower heart chambers (the ventricles) can't keep up. This means your heart beats in an uncoordinated manner, leading to an irregular, rapid heart rate (arrhythmia) and increasing stroke risk.
The incidence of undiagnosed AF in the community could be as high as one in 200 in the 40s and over age group, the annual scientific meeting of the Australasian College for Emergency Medicine was told in Sydney (21 Nov 2011).
With Australian Bureau of Statistics data showing more than 10 million Australians are aged 40 or older, around 50,000 may have AF based on this estimate.
Professor Ben Freedman, professor of cardiology at Concord Hospital and deputy dean of the Sydney Medical School, told the meeting his study of more than 1000 people aged over 40 who were having an electrocardiogram (ECG) check before surgery showed 3.1 per cent had AF.
And 0.5 per cent of people tested had AF that was not previously recognised and was not associated with symptoms or an elevated heart rate.
"This means there's a lot of people out there who have AF who don't know about it," Professor Freedman said.
AF episodes without symptoms were more common than AF episodes with symptoms, and so-called 'silent' AF (without symptoms) still led to stroke.
This is because the abnormal heartbeat in AF can allow blood to pool inside the heart and form a blood clot. If this clot breaks loose and travels in the blood vessels to the brain it can cause a stroke.
"The first time many stroke patients knew they had AF was when they [had a] stroke, and stroke is a very poor warning symptom of AF," Professor Freedman said.
Last Reviewed: 28 November 2011
- 1. Freedman B. Atrial fibrillation. Presentation to the Annual Scientific Meeting of the Australasian College for Emergency Medicine; Sydney, NSW; 21-24 November 2011. http://www.acem2011.com/files/pdf/ACEM-2011-program-final-for-web.pdf (accessed Nov 2011).
2. Australasian College for Emergency Medicine. Atrial fibrillation incidence increasing in Australia – and many don’t know they have it [news] (21 Nov 2011). http://www.acem.org.au/media/media_releases/monday_freedman_af.pdf (accessed Nov 2011).
