On Wednesday, Apple unveiled the next generation of the Apple Watch—and it has some notable new features. Like many new tech roll-outs, the watch is thinner and faster than watches that came before it, but the updated version also has several unique options for tracking a person’s heart health.
Previous Apple Watches have always had a heart monitor, but the new version can perform an electrocardiogram (also known as EKG or ECG), a test that measures the electrical activity of your heartbeat. What's more, the new Apple Watch's ECG feature is FDA-cleared to detect atrial fibrillation (an irregular heart rate that increases your risk for stroke and heart failure) and to give users notifications that their heartbeat is irregular. The watch also notes when a person’s heart rate is too low.
Users will be required to go through education through an app before they can unlock the ECG feature. Additionally, the FDA says in the approvals that, although the ECG feature can "determine the presence" of an atrial fibrillation, neither feature should be used for the purposes of diagnosis or is intended to "replace traditional methods of diagnosis or treatment." The features are also not intended to be used by people under age 22 or by people who have had previous atrial fibrillations or other arrhythmias.
There is another ECG-enabled device that’s received FDA clearance. It’s called AliveCor’s Kardiaband device, and it's a watch band and app that works with the Apple Watch. (However, it's not built into the watch itself like the new feature.) AliveCor also makes a personal ECG monitor called KardiaMobile that can be used with your phone.
The Apple Watch’s ECG and the ability to detect atrial fibrillation (an irregular heart rate that increases your risk for stroke and heart failure) will launch later this year, while the feature that detects a too-low heart rate will launch later this month with the Watch OS 5.
The Apple Watch's ECG feature is different from an ECG you'd get at your doctor's office in a few key ways.
Typically, your doctor will want you to have an ECG when you have irregularities in your heart (called arrhythmia), chest pain, structural problems with your heart's chambers, a previous heart attack, or ongoing heart disease treatment like a pacemaker, the Mayo Clinic says. But your doctor will also likely want to run an ECG if you have heart palpitations, a rapid pulse, shortness of breath, have been dizzy or confused, or are having weakness, fatigue, or a drop in your ability to exercise.
But standard ECGs (which are done at your doctor's office) can only tell your doctor what's going on if you're actually having symptoms while it's being conducted. So, for instance, if you've been having heart palpitations but feel just fine when you're undergoing the ECG, it's probably not going to detect anything, Shephal Doshi, M.D., director of cardiac electrophysiology and pacing at Providence Saint John’s Health Center in Santa Monica, Calif., tells SELF.
That's why your doctor may want you to use a different type of heart monitoring device that you can wear more consistently—such as a Holter monitor that straps onto your chest—to try to figure out what's going on, the Mayo Clinic says. This is where the Apple Watch's ECG might be helpful, Dr. Doshi says: If it's accurate, it can help your doctor pinpoint your heartbeat's electrical activity at the time you report feeling symptoms.
This seems great in theory, but doctors are a little wary.
“It seems like a wonderful idea and I’m sure there are some potential upsides to it," Micah Eimer, M.D., a cardiologist and medical director for the Northwestern Medicine Glenview and Deerfield Outpatient Centers, tells SELF. But Dr. Eimer worries "a lot" about the potential for false positives, or indications that something is wrong when it isn't.
For instance, while having a low heart rate (below 60 beats per minute) can be a sign of a heart issue, thyroid disorder, sleep apnea, or a side effect of high blood pressure medications, in many cases, it's totally harmless—especially if you're a serious athlete.
Long-distance runners, for example, are prone to having lower heart rates (bradycardia), Dr. Doshi says. If you're not an athlete, having a watch that detects bradycardia could tip you off that something isn't right with your heart and prompt you to seek care, Dr. Doshi says. But it could also give you a false positive and freak you out for no reason.
Additionally, things that are normal and known to be normal to cardiologists could be alarming to an Apple Watch user, like the fact that your heart rate can drop down to 30 or 40 beats per minute when you’re sleeping (which would apparently trigger an alert). That, and other false positives, may lead to people rushing to the ER and flooding the medical system when they don’t need to, he says.
The ECG you'd get at your doctor's office gathers information from 12 areas of your heart, the Mayo Clinic explains. But the Apple Watch only gives you one ECG reading, according to the FDA's approval letter, similar to a Lead I ECG (essentially one part of the standard 12-part ECG). But it’s hard to say how accurate the watch heart data will be compared to medical-grade monitors that doctors use until more information (and research) about the Watch's new capability is available.
“In theory, it will provide the ability to monitor patients in real time but we don’t yet understand how accurate this signal will be,” Dr. Doshi says. “In the past, devices like that have not been so accurate.”
There’s also the question of what to do with all the data. All of the data collected can be sent to your doctor in a PDF, Apple says in a press release. While that can be helpful in some situations, it can also be really tricky, Dr. Doshi says. “Who is going to be analyzing that data, and is there going to be proper follow-up?” he questions. “We use medical grade monitors all the time and they generate a lot of data. A lot of that is noise and can be very tricky even for trained users to figure out what’s real and what’s not.”
Some overzealous users may also overload their doctor with excess information (as Dr. Doshi is already seeing with AliveCor users). “There are some patients who start sending you EKGs every 30 minutes, which can become a challenge. That can cause a huge data dump,” Dr. Doshi says.
Finally, Dr. Eimer is concerned that a patient may have unusual symptoms, like chest pain, but write them off because their watch says they’re OK. “The doesn’t mean they’re actually OK,” he says. “Having chest pain may or may not cause an abnormal EKG. It’s a lot more complicated than it appears.”
Still, experts see some possible benefits to wearing a device like this.
If you have an irregular heart beat, a history of heart disease or heart attack, or a pacemaker, the Apple Watch's ECG could potentially provide helpful information for your doctor—especially if you're having symptoms outside of the doctor's office. But any symptoms you experience would still require a visit to the doctor's office to sort out, and would likely involve more traditional testing.
Dr. Elmer also says some people may see a doctor for abnormal readings who wouldn’t otherwise have sought care. He sees one or two patients a year who found that their heart rates were off thanks to a consumer heart monitoring device and ended up learning they had an atrial fibrillation or other issue. “That’s a big win, a big save,” he says. But that's obviously not common.
Also, some patients require continuous heart rate monitoring, which is currently performed with a device implanted under a patient's skin, Dr. Doshi explains. So, if the Apple Watch is accurate, it presents an opportunity for continuous heart rate monitoring that's less invasive.
So, although doctors aren’t exactly recommending that patients go out and buy one of these, they say there’s potential—provided it works well and people use it correctly and with common sense. “If you’re having heart problems, go to your doctor," Dr. Eimer says. "Watches may serve a very narrow purpose, but they certainly don’t tell the whole story when it comes to your heart.”