Cardiologist DR ANDREW NG talks to us about how new technology in smart watches and devices is aiding our heart health and detection and treatment of atrial fibrillation.
What is atrial fibrillation, and how common is it?
Atrial fibrillation is a heart rhythm problem characterised by an irregular heartbeat. One person out of every five will develop AF in their lifetime, most commonly people aged over 80. If you have atrial fibrillation, you have unpredictable heartbeats – they can be very fast, or very slow. It’s a bit like rain drops – you can’t predict exactly when the next drop will fall.
How has detection and diagnosis of AF traditionally been carried out?
Atrial fibrillation is traditionally diagnosed by symptoms. Patients might have a palpitation or feel an abnormal heartbeat, for example; some might have a syncope, which is a sudden loss of consciousness, or a “blackout”; others might just feel a bit dizzy and then return to normal afterwards. Once there are these suggestive symptoms, doctors can use an ECG (electrocardiogram) to assess the heart rhythm.
Tell us about some technological advances that have been made in detecting and treating atrial fibrillation.
One tricky thing about atrial fibrillation is that it may only happen occasionally. Sometimes, a patient will have AF for an hour and then it won’t come back for a few months. Some patients don’t have symptoms at all and may not even know they have the condition. However, there are serious consequences if AF is undetected for a long time. New technologies can help with detection. For example, the Ambulatory ECG is a sticker that attaches to a patient’s chest and monitors their heart rhythm for a period of several days to weeks. The sticker records instances of AF or other heart problems and informs the doctor.
Thanks to further enhancements in technology, some smart watches can now detect AF with decent accuracy – 84 percent accuracy in some commercially available watches, in fact. This makes them a useful screening tool, as the watch will continuously monitor the heart rhythm. At the same time, 84 percent accuracy does also mean there is 16 percent inaccuracy. So we still need traditional hospital-grade devices to confirm a diagnosis. But smart watches are a good reminder to patients that it’s time to see their doctor and have a heart check-up for their issues.
How would I specifically use a smart phone or watch to detect atrial fibrillation?
If you have a smart watch, it’s as easy as using an app in the watch to detect AF. If you’re using a smart phone, there’s a special device that connects from the phone to your two thumbs and then the heart rhythm can be recorded by pressing on the device. What’s one of the biggest benefits of these smart monitoring devices? Previously, I had to rely a lot on patient’s descriptions of their symptoms; yet AF symptoms can vary so much from patient to patient that it can be difficult to gauge the severity of the disease.
With these devices, we can actually read into the precise heart rhythm at a particular point in time; for example, if a patient tells me they had an abnormal heartbeat last night, I can read the findings from that exact time and interpret those findings in conjunction with the symptoms. I can then make a firm conclusion about whether the symptoms are really reflective of the severity of the disease.
This is helpful in devising the ideal treatment plan, too. For example, if a patient typically has a fast heart rate at a certain time of day, I can specifically add a medicine to be taken just before that period of time; that way, the patient’s symptoms can be targeted with specific treatment.
What limitations are there with these new technologies?
Since this is generally for home use, the person has to be familiar with operating a smart phone or smart watch. The first time you use them they may require setting up, but after that they’re very easy to use. However, the patient must also be motivated to use the device. If you don’t turn on the app or read the data, or you don’t send it to the doctor to interpret it for you, then you won’t get much help from these monitoring devices. The third thing is you need a good doctor to acutely interpret the information, as it’s only a first step in an entire diagnosis.
What are some things we can do from a health perspective to prevent and manage atrial fibrillation?
Since high blood pressure can cause atrial fibrillation, I suggest that everyone who is 20 or older should monitor their blood pressure. If it’s normal, check it once a month; if it’s high, check it every day and try to control it in the normal range (120/80 is considered normal today).
As for atrial fibrillation, there are two main considerations. First, we want to fix the heart rate as close to normal as possible – for example, about 60 beats per minute at rest, increasing up to 100 or 120 with exercise, and without any episodes of very slow or very fast heart rate. There are medicines available to help with heart rate control.
The second consideration is stroke prevention. The irregular heart rate associated with atrial fibrillation can mean there’s a disturbance of the blood flow inside the heart. This, in turn, can lead to the formation of blood clots in the heart. If a clot moves in the blood to the brain, it can block the blood vessel in the brain and cause a stroke. Patients with AF are five times more likely to have a stroke; actually, around 20 to 30 percent of strokes are caused by atrial fibrillation. To reduce this chance, we usually prescribe a blood thinner.
How did you come to choose cardiology as a specialty?
One thing I really like about cardiology is that it offers a cure for so many patients. So, for someone with coronary artery obstruction, there are technologies I can use to open up the blocked vessels and restore them to normal. It’s challenging, and it requires pretty rigorous training, but the whole experience is very rewarding for me and for patients as well.
Speaking of training, tell us about your time at Harvard. I trained at Harvard Medical School around six years ago – I was a fellow there specialising in cardiology intervention. That was a phenomenal year; I trained from seven in the morning to six in the evening. Then, during the night, I needed to be ready to do emergency surgery (on patients who’d had heart attacks, for instance). Even during snow storms, I’d have to get up in the middle of the night and drive through the snow to the hospital. One night, after surgery, my car was covered in snow – it was three in the morning and I had to shovel the car out. I was afraid it would break down and I wouldn’t be able to get home – fortunately, it started. A unique experience!
What do you like to do in HK when you’re not working?
In autumn and winter, I like to hike – there are so many beautiful mountains in Hong Kong. In the summer, I like going to the beach and doing water sports like windsurfing.
This article first appeared in the Autumn 2022 issue of Expat Living magazine. Subscribe now so you never miss an issue.