Watch your heart

The newest version of the Apple Watch is inching towards becoming a medical device. With a built-in electrocardiogram, it is said to be the world's first wearable available to consumers over the counter to offer such medical functionality.

Launched last month, the Apple Watch Series 4 has received approval from the US Food and Drug Administration to operate an on-demand electrocardiogram. Though such an advancement could mean a leap forward in personal healthcare, it is still a subject of debate as to whether this incarnation of the Apple Watch will prove to be a useful monitoring tool for the heart or a potential healthcare headache, responsible for triggering false alarms.

Cardiologist Dr Krisda Vilaiwatanakorn said that wearable devices with medical features can be considered supplementary equipment to keep an eye on the heart. However, they should by no means be the main source of information for medical diagnosis.

"These devices can give preliminary data to suggest if something should be done. But users should not solely depend on them or be overly alarmed by the results without consulting a specialist," he said.

An electrocardiogram, also known as an EKG or ECG, is a diagnostic procedure to measure and record the electrical activity of the heart. The heart has its own electrical system for making and conducting signals that trigger the heartbeat. The electricity is generated by a group of cells in the heart's wall called the SA Node, which signals the atria, or upper chambers, to contract. Then it sends signals to the AV Node, another group of cells, to trigger the ventricles, or lower chambers, to contract.

So to check the whole picture of the heart and how each chamber functions, Dr Krisda explained, EKG comes into play, as it is designed to monitor the electrical activity from different angles in order to identify and locate the heart's pathology.

There are several markers to monitor the pattern of electricity. A full-scale EKG used by cardiologists to check for abnormalities in the heart usually comprises 12 leads, imaginary lines between two EKG electrodes. A 12-lead EKG procedure uses 10 electrodes -- six for the chest and four for the limbs.

"EKG is a standard diagnostic protocol for patients who come in with heart-related symptoms like chest pain," said the cardiologist. "It works best when symptoms appear while the EKG is being carried out. Nonetheless, for those with heart-related conditions, an EKG that shows normal results do not mean the end of the story. A specialist might need to check cardiac markers or the patient's family history, or conduct a physical examination to assess the risk of disease."

Painless and quick, an EKG can be used to check the heart's rhythm and blood flow, and detect heart attacks or other abnormalities, such as thickened heart muscles and coronary artery diseases.

According to Dr Krisda, the biggest difference between wearable-scale and hospital-scale EKGs is the number of leads. While a full-scale EKG contains 12 leads, a wearable-scale EKG is a single-lead detector.

"A single-lead EKG can only check heart rhythm and if the heart is beating normally. However, it doesn't detect electricity that runs to and from other parts of the body. Illnesses like thickened heart muscle, cardiomegaly [enlarged heart] and coronary artery diseases can only be confirmed by a 12-lead EKG," he said.

Despite such limitations, Dr Krisda is of the opinion that wearable devices with built-in EKG can be helpful, especially among the elderly, as many of them do not feel like complaining about their health or visiting a specialist for regular screening.

"Of course, a wearable is more convenient than a portable EKG device because it does not require any complicated installing instructions. And it is FDA-approved, so the results are reliable to a certain extent. It helps monitor the heart's health, which means it takes better care of us, especially in terms of prevention.

"The important thing to note here is that the device will not do harm unless users become overly anxious about it. Whether your smartwatch goes off or not, you have to visit a doctor if any abnormalities develop. On the other hand, if you look at your device all day and become too stressed out about the results you keep reading, then that means it's doing more harm than good."

With or without a smartwatch, taking care of the heart is paramount and that requires human attention rather than medical technology. First, Dr Krisda advises starting with something that can be amended.

"Smoking is a threat to the heart," he said. "So if you smoke, quit. Also salty diets can lead to high blood pressure, which puts more pressure on the heart. Food that is high in fat, especially fried and deep-fried dishes, can lead to high cholesterol which is also detrimental to the heart's health."

As with anything else, exercise is crucial.

"It's recommended that you work out five times a week. Each time should last no less than 30 minutes. If you do heavy exercise, the number can go down to three times a week. If you wear a smartwatch, keep an appropriate heart rate while exercising," said Dr Krisda. Each individual's target heart rate for exercise varies, but should be around 70% of one's maximum heart rate for moderate-intensity physical activity. The maximum rate is based on a person's age and can be calculated by subtracting the age from 220. If you are 40 years old, for instance, your target heart rate should be 70% of 180 or around 126 beats per minute (bpm).

"For those without a smartwatch, just use your intuition," he said. "You should feel exhausted during exercise. An easy way to measure the level of exhaustion is through your ability to speak. While working out, you should be able to talk but with some difficulty. If you can still chat or have a long conversation with friends, it means you're not doing it hard enough. Conversely, if you feel so tired you are unable to speak, that's probably too much."