Tiny device inserted in chest alerts doctors to heart issues
One November morning in 2016, Mr Ng Kok Seng's heart stopped beating for six seconds, but the retiree, then 62, did not notice and carried on with his daily activities.
He found out later in the day after a tiny device in his chest, known as an insertable cardiac monitor (ICM), alerted a team at the National University Health System (NUHS), which called him and told him to go for an emergency consultation.
The retiree learnt he had atrial fibrillation, a heart rhythm disorder that causes the organ to beat much faster than usual - over 300 beats a minute, up from the usual 60 to 80. It is also responsible for about a quarter of all strokes. The ICM was inserted in Mr Ng after he had a stroke in October 2016.
Dr Seow Swee Chong, a senior consultant at the National University Heart Centre's department of cardiology who treated Mr Ng, said his experience is common among patients with atrial fibrillation.
"Around 80 per cent to 90 per cent of our patients who have atrial fibrillation don't have any symptoms," he said.
Typically, atrial fibrillation is diagnosed using an electrocardiogram. Dr Pipin Kojodjojo, another senior consultant at the department of cardiology, said this method has problems.
"Atrial fibrillation can come and go... if you just had a check-up yesterday, it doesn't mean you can't have the condition today," said Dr Pipin.
So in 2015, the heart rhythm and stroke teams at the National University Hospital and National University Heart Centre did a study to find a better way to detect atrial fibrillation.
A total of 205 patients like Mr Ng, who had strokes with no known cause, were implanted with ICMs. The device, which is roughly the length of an AAA battery but flatter, takes around three minutes to be inserted into a patient under local anaesthesia via injection.
ICMs have a battery life of about three years and can record and analyse patients' heart rhythms throughout the day.
In the event of a heart rhythm disturbance, a team at NUHS is alerted. Once the condition is detected, treatment can be done to reduce the risk of stroke.
Atrial fibrillation was found in about 12 per cent of the patients who had ICMs inserted, whose condition might have otherwise been missed.
Dr Seow noted that all the patients in the study who had their condition detected were given medication and have not been hit by a second stroke.
In Mr Ng's case, after his ICM alerted Dr Seow that he had an abnormal heart rhythm, he had a pacemaker inserted and was given anticoagulants.
He said: "Because of the ICM, the atrial fibrillation was detected... It saved me."
Given its success, Ng Teng Fong General Hospital will also be introducing ICMs to detect atrial fibrillation in patients with unexplained stroke. This will start in December.
NUHS will also be expanding the operating hours of its nurse-led clinic for atrial fibrillation at Bukit Batok Polyclinic to better facilitate management of the condition.
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