UAB Medicine News
Wearable Devices are Convenient for Monitoring Heart Rhythms
Thanks to advances in wearable health-tracking devices, people can monitor their heart rhythms much easier now. Commercially available heart monitors may provide early detection of irregularities, but experts say the devices should be used in partnership with a doctor.
Until recently, anyone who experienced a variation in heart rhythm (arrhythmia) normally would see a doctor for evaluation. But, like the difficulty in getting your car engine’s knocking sound to happen while in the mechanic shop, it’s hard have an irregular heartbeat coincide with a visit to the clinic. For that reason, doctors would prescribe a traditional Holter monitor (a small battery-operated device with leads that attach to the chest) or other remote rhythm-monitoring device to track results over a specific period of time. Since arrhythmia can come and go, remote monitoring plays an important role in diagnosis.
With wearable devices being produced as consumer products, however, tracking irregular heart rhythms outside the clinic has become even easier. Tom McElderry, MD, an electrophysiologist with the UAB Cardiovascular Institute, describes the benefits of this new technology.
“Wearable devices are particularly helpful for people who have infrequent episodes of arrhythmia,” Dr. McElderry says. “Historically, our options have been to have patients wear prescription devices that capture episodes over a time span of 24 hours, two weeks, or 30 days. The advantage of an Apple Watch or a KardiaMobile monitor is that the patient owns it, so they can monitor for any length of time to detect arrhythmia.”
There are various technologies used in wearable devices. For example, the Apple Watch uses an optical sensor to measure heart rate. Because blood reflects red light and absorbs green light, the Apple Watch uses green LED lights paired with sensors to detect the amount of blood flowing through the wrist at any given moment. When the heart beats and sends blood through the wrist, the green light absorption is greater at that moment. Between beats, less absorption takes place. By flashing its LED lights hundreds of times per second, the Apple Watch can calculate the number of times the heart beats each minute. Sudden changes in that number may indicate arrhythmia.
Detecting Dangerous Conditions
Arrhythmia occurs when the electrical pathways that make each part of the heart beat in sequence develop short circuits or other irregularities, affecting the amount of blood the heart can pump. The consequences are not always serious. For most people who have not had heart attacks in the past and don’t have serious heart conditions, Dr. McElderry says such minor arrhythmias are usually just a nuisance. They can be resolved by avoiding caffeine and certain cold medicines, or by starting medications such as beta-blockers or calcium channel blockers. Atrial fibrillation (Afib), however, can be a dangerous arrhythmia.
If left untreated, the rapid heartbeat of Afib can weaken the heart muscle. It may may restrict blood flow to other parts of the body, increasing the risk for various complications, the most serious being stroke. Afib is estimated to affect 2.7 million–6.1 million people in the United States. The range is great because the condition often goes undiagnosed, usually due to the absence of symptoms. In that context, for some people, a wearable heart monitor may be a good first step in identifying a serious health condition.
“If Afib is detected by the device, you can contact your doctor to determine what treatment is needed,” Dr. McElderry says. “There are other advantages, too. For example, someone who has Afib episodes might never have a physical sensation, but perhaps they do have an increased heart rate with each episode. From that point, the device’s heart rate monitoring function will be useful for staying alert to another episode of Afib.”
Provider Diagnosis Still Needed
With some devices, after an irregular rhythm is detected, the user can then take an electrocardiogram (ECG or EKG), which records the timing and strength of the electrical signals that make the heart beat. This information can be forwarded to a provider. By looking at an ECG, a doctor can study a heart rhythm and look for irregularities and make a diagnosis. Dr. McElderry notes that patients should use these devices in conjunction with seeing a qualified provider for diagnosis.
“You still need a qualified provider to read over all the data that these devices give you, because there are many categories of irregular rhythms that the monitor may not indicate,” Dr. McElderry says. “Whatever device you have, it typically makes an initial interpretation. False readings are possible. We recommend that you have your provider look at that data.”
The American Heart Association, American College of Cardiology, and the Heart Rhythm Society offer the same recommendation. A main concern among medical professionals is that people may rely on these devices but not consult with their provider. Also, although some mobile medical apps and accessories are approved by the FDA as medical devices, most are not. Many medical experts are concerned that false readings may lead to over-reporting, additional treatment, and unneeded testing.
But as the technology advances, most health care professionals anticipate mobile health tracking will become the new normal, just as blood tests, STD tests, and blood pressure monitors are now part of home care. There is real potential for wearable devices to improve cardiovascular care outside the doctor’s office.
“I think this will allow people to be diagnosed much sooner than they would have been in the past,” Dr. McElderry says. “Providers will create workflows in their clinics that will enable patients to forward data to a doctor or nurse for interpretation. Currently, our own electrophysiology department is piloting a program specifically for that purpose. We’re in the early stage of determining what infrastructure we can use to create that mechanism for receiving data from various consumer devices.”
Click here to learn more about how electrophysiologists at the UAB Cardiovascular Institute diagnose and treat heart rhythm disorders