Two-week monitor after unexplained fainting identifies ‘life-threatening’ heart conditions

Using the two-week monitor, which is about the size of a car key fob, more than doubled the detection rate of heart rhythm problems in the study of 2,234 people. After one year, heart rhythm problems were identified in 22 per cent in the monitor group compared to nine per cent of those who received standard care.

The death rate after one year in the two-week monitoring group, at 1.5 per cent, was almost half that of the standard care group, at 2.9 per cent 

Heart rhythm problems, known as arrhythmias, were identified in an average of 22 days in those with chest-worn monitors, compared to 54.5 days with standard care. This included life-threatening arrhythmias like complete heart block, ventricular tachycardia, and a pause in the heartbeat of over six seconds.  

As a result of increased and quicker detection, more people who used the chest-worn monitor started treatment for their arrhythmia. The findings are also published today in the New England Journal of Medicine.

Professor Matthew Reed, Professor of Emergency Medicine at the University of Edinburgh, who led the study, said:

“We were able to begin patient monitoring within 72 hours of people arriving at A&E, much faster than the current standard. Continuous data on a patient’s heart rhythm for two weeks is invaluable to cardiologists when they are trying to diagnose an arrhythmia. As the results show, more patients with hidden heart rhythm problems were identified, and their treatment could be sped up.

“We believe that the lower death rate seen for this group is strong evidence that this new strategy can save lives. Hopefully it will be adopted by hospitals across the country, so that fewer people with a potentially life-threatening condition slip through the net.”

The researchers estimate that around 650,000 people visit A&E with unexplained fainting each year in the UK. Regular unexplained fainting can seriously impact patients’ lives, preventing them from doing day-to-day tasks like driving. Although in many cases the cause is harmless, fainting episodes can be a sign of abnormal heart rhythms, some of which can be dangerous.

Arrhythmias in these patients are hard to diagnose. People who have fainted have usually recovered by the time they reach A&E, meaning their heart rhythm has likely returned to normal, and tests performed in A&E won’t show any abnormalities.

Currently, patients with unexplained fainting are referred for tests such as a Holter monitor – a small wearable device that records the heart’s rhythm – to try and identify arrhythmias.  But a Holter monitor is usually only worn for 48 hours, so can only identify an arrhythmia in this small time window. 

Patients must also attend an outpatient cardiology clinic first, meaning that monitoring is done at any point from six weeks to two years after they attend A&E.  

The new heart monitor is smaller and is worn in the middle of the chest. It can be worn continuously for the two-week period. In the trial, half of the study volunteers who attended one of 45 UK A&E departments with unexplained fainting were fitted with the new monitor. The other half received the current standard monitoring.

Data from the monitors were sent to clinicians after the two-week monitoring period, who then determined whether their recordings showed signs of an arrhythmia and if treatment was needed. If the monitor had picked up a serious arrythmia, the patient’s clinician was alerted within 24 working hours. 

There was no difference in the average number of fainting episodes reported after one year – 1.37 in the monitor group compared to 1.58 in the standard care group. 

However, improved detection of arrhythmias meant two-week monitoring improved the number of people receiving treatment. For the monitoring group, 10.8 percent were given anti-arrhythmic medication, and 6.8 per cent had a pacemaker implanted, versus 7.3 per cent and 4.6 per cent respectively for the standard care group [4].

The researchers hope that now the new strategy has been shown to help doctors treat more dangerous heart problems, and reduce death rates, it will become standard practice in the NHS.

Professor Bryan Williams, Chief Scientific and Medical Officer at the British Heart Foundation, which funded the trial, said:

“This large trial is a good example of how BHF investment in research can drive life changing innovations in healthcare. The study shows that monitoring the heart with simple new technology after a patient has had a sudden collapse can identify potentially life-threatening disturbances in heart rhythm that can be treated to reduce risk of death. 

“The results of this trial should certainly help inform future clinical practice when treating patients with sudden unexplained collapse in the future.”

To arrange interviews or for more information, contact the BHF’s Newsdesk on 020 7554 0164 or email newsdesk@bhf.org.uk