British scientists believe treating stroke survivors for atrial fibrillation (AF) could prevent many patients from going on to develop dementia.
University of East Anglia researchers examined almost 50,000 patients' records and discovered that suffering AF after a stroke more than doubles the risk of dementia.
Doctors are now calling for an investigation into whether a stronger course of treatment to control AF has the potential to delay or even prevent the onset of dementia.
Around 500,000 Britons are thought to be affected by AF and it is the most common heart rhythm disturbance.
The condition is not usually life-threatening in itself, but it does increase the risk of people suffering strokes.
Doctors often prescribe blood-thinning drugs and medication to slow irregular heartbeats to combat stroke risks.
But after the study, researchers now believe tighter management of AF could offer a degree of protection against dementia.
They examined and compared the results of 15 separate studies to see how many patients with and without AF went on to develop dementia.
Results showed that an estimated 25% of patients with stroke and atrial fibrillation went on to develop the illness, with these patients 2.4 times more likely to suffer dementia than stroke survivors with no heart condition.
Their findings have been published in the Neurology journal.
Lead researcher Dr Phyo Kyaw said: "These results may help us identify potential treatments that could help delay or even prevent the onset of dementia.
"Options could include more rigorous management of cardiovascular risk factors or of AF, particularly in stroke patients."