Thousands at risk from ‘invisible’ heart fault

THOUSANDS of people in the UK could be living with a hidden heart condition that puts them at risk of stroke and dementia. Atrial fibrillation is the most common type of irregular heart rhythm, known to affect about 1.3million in the UK. But experts believe many more people are living with the condition undetected.

They may experience symptoms such as palpitations, breathlessness and fatigue and their pulse will also often feel abnormal, with some beats stronger than others. Some will not notice any signs of the condition, and for others the symptoms can come and go – occurring for just a matter of seconds every few weeks.

But an irregular pulse can lead to blood pooling and clotting in the chambers of the heart. These clots can break away, potentially causing a blockage and triggering a catastrophic stroke, with little warning.

Now, early findings of a major study funded by the British Heart Foundation (BHF) suggest that as many as five per cent of men over the age of 65 could be living with ‘silent’ atrial fibrillation. The figure is expected to be about half that among women of the same age.

‘You can have atrial fibrillation without any symptoms,’ explains Professor Barbara Casadei, BHF Professor of Cardiovascular Medicine at the University of Oxford. ‘But the fact that you do not have any symptoms does not mean you are not at risk.’

When the heart beats normally, it contracts regularly to squeeze blood out and around the body, before relaxing to let blood back in. This process is controlled by tiny electrical messages, sent by the sinus node – the heart’s in-built pacemaker.

Atrial fibrillation occurs when the upper chambers of the heart – known as the atria – also produce unco-ordinated electrical messages. This makes the upper chambers contract randomly and twitch, causing an irregular, or sometimes fast, heartbeat.

Evidence suggests atrial fibrillation also increases the risk of dementia by as much as 50 per cent. Those with the condition may suffer from ministrokes, too small to cause any outward symptoms – but which damage the brain. Over time, this is thought to reduce mental function. ‘You may not have the full symptoms of a stroke, but neurons are being destroyed,’ Prof Casadei explains. ‘The brain doesn’t make new neurons, so you are going to lose connectivity, lose neurons and accelerate cognitive decline.’

The new study is tracking the heart rhythms of 40,000 participants over the age of 65. Each one will wear a stick-on chest patch, containing a microchip which continually records and stores electrical activity, over a two-week period. They will also have scans, undergo repeated cognitive tests and be followed up for life using their medical records.

‘We want to know whether it matters if people have even very short episodes of this irregular arrhythmia, as far as their brain health is concerned,’ Prof Casadei explains.

The results are expected to help doctors determine which patients are most at risk – and who should be treated with blood-thinning drugs, known as anticoagulants. ‘We hope that by having all this information, we will know which patients are most at risk,’ Prof Casadei says.

A pilot study including 7,000 over 60s detected 60 cases of ‘silent’ atrial fibrillation. This was about three per cent of men and one-and-a-half per cent of women.