Cardiology researchers at the Royal Adelaide Hospital (RAH) have identified a link between a common heart rhythm disorder and risk of falls and syncope: a temporary loss of consciousness usually related to insufficient blood flow to the brain.
Atrial Fibrillation (AF), a common heart rhythm disorder that causes an irregular heartbeat and which, in some patients, can cause debilitating symptoms, lead to stroke or the development of heart failure. It has become the most common heart-related reason people in Australia present to hospital – even more than presentations with heart attacks and heart failure.
Dr Varun Malik, a Cardiologist at the RAH, has now determined that AF is associated with an increased risk of syncope and falls due to changes in the autonomic nervous system.
“Research conducted at Central Adelaide LHN has identified a novel abnormality in the way patients with AF recognise and adapt to changes in blood volume,” said Dr Malik, speaking at the RAHsearch 2021 event.
The autonomic nervous system regulates heart function with every heartbeat. It is critical to our health – without it, we couldn’t even maintain our upright posture. The nerves in the autonomic nervous system gather information from the heart and then use this to maintain blood volume and blood pressure (cardiovascular homeostasis).
In a prior study, the researchers demonstrated evidence of autonomic disfunction in patients with AF.
They placed patients’ legs into a box which applies negative air pressure surrounding the limbs, causing blood to drain from the heart, and pool it in the legs. It is very similar to the techniques used to measure the cardiovascular effects of weightlessness in astronauts who have returned from space.
“This work provides mechanistic data to support earlier rhythm management in patients with AF to help prevent these longer-term problems in future and they also present a potential therapeutic target that can be used to develop treatments and devices that are capable of modulating the autonomic nervous system ‘neuromodulation’ in the management of AF,” said Dr Malik.
Read more about the research
Malik, Varun, et al. “Atrial fibrillation is associated with syncope and falls in older adults: a systematic review and meta-analysis.” Mayo Clinic Proceedings. Vol. 95. No. 4. Elsevier, 2020. Read the article.
Malik, Varun, et al. “Clinical evidence of autonomic dysfunction due to atrial fibrillation: implications for rhythm control strategy.” Journal of Interventional Cardiac Electrophysiology 54.3 (2019): 299-307. Read the article.