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Wearable devices and the revolution of cardiology via continuous care, remote monitoring
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Wearable technology, including wrist-worn smartwatches and fitness monitors, is no longer the “future” of medicine. The use of wearable technologies and the potential in cardiology has become an intense topic of discussion in recent years. Of particular interest this year was the release of the Apple Heart Study data at the American College of Cardiology Scientific Session in March.
Anticipated results of the Apple Heart Study, which evaluated how well a smartwatch (Apple Watch) could identify atrial fibrillation and prompt subsequent clinical evaluation to confirm the diagnosis, showed that the wearable technology was beneficial.
Despite how some physicians view the Apple Heart Study results, the large research showed that new technologies, such as the Apple Watch and other wearables, have the potential to complement health care systems and strategies to identify AF and other conditions. Still, more work must be done to incorporate this large mass of data into existing health care systems.
“Using new technologies can identify otherwise undiagnosed AF before it causes problems,” Cardiology Today Editorial Board Member and Next Gen Innovator Seth S. Martin, MD, MHS, FACC, FAHA, FASPC, associate professor of medicine and cardiologist at the Johns Hopkins Ciccarone Center for the Prevention of Cardiovascular Disease, said in an interview. “Once potential AF is found in this new way, tie-in with the health care system is necessary to confirm diagnosis, assess AF burden and sort out appropriate treatment.”
Even beyond AF, Cardiology Today interviewed leading physicians about the potential of wearable technologies in cardiology, and current challenges.
Broad potential of new technologies
Consumer-grade wearables are capable of measuring several factors that are important to cardiologists, including physical activity, which is assessed through an accelerometer and a gyroscope. Wearables can also calculate how many steps a patient is taking, which can be a helpful measurement for cardiologists, although more research is needed to determine how this metric affects the heart and health in general.
Several devices have received FDA clearance to be used in conjunction with the Apple Watch and iPhone to detect several types of arrhythmias. ECG technology (KardiaMobile, AliveCor) received two 510(k) clearances in April for its ability to detect bradycardia and tachycardia. A month later, a novel six-lead personal ECG device (KardiaMobile 6L, AliveCor) was also cleared by the FDA to detect arrhythmias.
“The rapid evolution of technology is amazing,” Martin told Cardiology Today. “As we learn better and better what is really the optimal physical activity patterns for people and how do we best use these devices as a motivator, whether it’s giving badges, social networking or sending motivational messages, it is going to be a key area moving forward.”
Other factors that can be measured by wearables include heart rate, heart rate variability and sleep patterns.
“We’re now seeing these technologies ... which can identify periods of irregular heart rhythms,” Cardiology Today Next Gen Innovator Mintu P. Turakhia, MD, MAS, associate professor and executive director of the Center for Digital Health at Stanford University School of Medicine, said in an interview. “Some wearables also will identify episodes of very fast or very slow heart rates. The Apple Watch does that. Now, strikingly, we’ve seen the ability to record an ECG right off of the watch. That’s the spectrum of the data capture that it has.” Turakhia was a co-principal investigator for the Apple Heart Study.
Additional sensors are currently being developed and tested that can be used with wearables such as the Apple Watch to collect information on respiratory rates, oxygen saturations, BP measurements and autonomic tone measured by sweat.
“You can basically say that at some point in time, every organ in the human body will be digitized or could be read through some sensor, and the information from all these sensors then could be collated to help us better understand how the entire machine of the human body is working,” Cardiology Today Editorial Board Member Jagmeet P. Singh, MD, DPhil, associate chief of the cardiology division at Massachusetts General Hospital, told Cardiology Today.
Wearables are capable of generating a wealth of information, but how exactly to process and interpret all the data is still a topic of discussion and research among health care providers, experts said. This may involve the integration of artificial intelligence and additional clinical staff to cull through the data to produce a report that is easy for health care providers to interpret.
“Wearables provide opportunity to generate a health summary,” Nino Isakadze, MD, cardiology fellow at the Heart and Vascular Institute at Johns Hopkins University, told Cardiology Today. “That would essentially give you a summary of heart rate, physical activity, weight data and trends, and a symptom diary, then you can correlate those to patients’ lab data and physical exam when they come to their clinic visit and come up with a comprehensive, personalized care plan with them.”
Another concern that arises is wearable-generated data accuracy, as the devices are not technically medical grade, experts said. Although some health care providers are concerned about the risk for false positives and other inaccuracies from wearable devices, some studies have found that the data provide acceptable information. According to a study published in JMIR mHealth and uHealth in March, data generated from the Apple Watch 3 and Fitbit Charge 2 were acceptable regarding heart rate accuracy.
“Just because it’s not medical grade doesn’t mean that it’s not useful,” Kapil Parakh, MD, MPH, PhD, medical lead for Google Fit, adjunct assistant professor of medicine at Yale School of Medicine and chair of the American College of Cardiology’s Innovation Advisory Group, told Cardiology Today. “What you end up with is essentially a large volume of data, but it’s not necessary of medical-grade quality. It’s a matter of how to make use of and apply those data.”
Singh said it is important that future studies be conducted to further define how wearable technologies can be incorporated into clinical practice.
“As a first study of its kind, [the Apple Heart Study] is very reasonable and it creates a platform for other studies and other interventions that may be looked at using this technology,” Singh said.
Smartwatch shows promise
The large-scale, app-based Apple Heart Study — led by researchers at Stanford University School of Medicine — enrolled nearly 420,000 participants over 8 months.
Participants had to have an iPhone 5S or later and an Apple Watch Series 1, 2 or 3. The study did not include participants with the Apple Watch Series 4, which features an electrical heart rate sensor that can take an ECG using a dedicated ECG app, because enrollment concluded prior to the introduction of the device.
The researchers evaluated a mobile app that uses the smartwatch’s existing light sensor — or photoplethysmography — to intermittently measure blood flow activity and detect subtle changes that might indicate an irregular contraction or heartbeat. The Apple Watch generates a tachogram, which Turakhia described as a plot of time between heartbeats. If an irregular tachogram is present, then more frequent tachogram collection occurs. If five of six tachograms meet irregularity criteria, then an irregular pulse notification is sent to the user on their phone and watch. In the Apple Heart Study, participants who received this notification were then prompted to contact a telehealth study physician via the app. Based on a study video visit on the participant’s device, he or she would be directed to wear a study ambulatory ECG patch (BioTelemetry), sent by mail, for up to 7 days. After the patch was returned and read by cardiologists, the participant was directed to another telehealth study physician visit to discuss the results.
The data showed that 0.52% of patients received an irregular pulse notification, an important finding given concerns about the potential for over-notification, Turakhia said. The Apple Watch in the study had an 84% positive predictive value for simultaneous ECG patch-confirmed AF, which is comparable to insertable cardiac monitors.
Others may see it as a negative result. “Now one could look at it from another angle and say that there were 16% false positives or false negatives, so that could be a problem itself,” Singh said.
Not only were these patients notified of their irregular pulse, but many took the notification seriously; 57% of patients reported contacting a non-study provider after receiving the notification.
“What the Apple Heart Study does is it helps us improve our understanding of how wearable technologies such as the one we studied can enable individuals to identify potential conditions or disease,” Turakhia told Cardiology Today. “We know that undiagnosed AF is a big problem, and we know that treatment such as anticoagulation can prevent adverse outcomes and cardiovascular events. That’s the overall pretext of the unmet need.”
Monitoring patients
Wearables have the ability to monitor CV health in patients without CVD, although it still has yet to be determined how exactly to do that, experts said.
“The Apple Heart Study is just the beginning,” Turakhia said. “As we think about these signals, we can start looking ahead to other unmet needs in preventive medicine and in guiding health.”
This technology can help patients without CVD be more aware of their behaviors, especially regarding physical activity. For example, Google Fit currently has the ability to gauge how much physical activity a patient has completed to work toward the goals listed in the physical activity guidelines.
“We worked with the World Health Organization and the American Heart Association to develop a metric [for Google Fit] called ‘Heart Points’,” Parakh said. “You essentially earn one Heart Point for moderate activity like a brisk walk and two Heart Points for vigorous activity like going for a run.”
Wearables can be used to a certain extent as a complementary tool for disease management, although there currently is not a standardized approached to this, experts said.
“Right now, it’s really early to say what the optimal solutions are in terms of how patients should best self-manage AF or heart failure with direct feedback from their wearable or other devices,” Turakhia said. “Ambulatory ECG monitoring as a medical device still has an important role, but the paradigm of self-management will advance, just as it has for diabetes.”
Tracking physical activity and energy expenditures through wearables can also benefit patients with CVD. In a study published in JMIR mHealth and uHealth in March, researchers found that the Apple Watch measured heart rate with clinically acceptable accuracy in patients with CVD, which may become helpful with regard to cardiac rehabilitation.
“If you can measure energy expenditure, then it will help with not only physical activity, but will help people also regulate their body mass index and at the same time assess how certain activities influence their energy expenditure vs. in other individuals. There’s a lot of individual variability,” Singh said.
Sensors found in wearables can be used to monitor certain comorbidities in patients with HF, including hypertension, ischemic heart disease and diabetes, experts said. Triggers for patients with HF, such as AF, electrolyte abnormalities and temperature changes, can also be tracked with wearables.
There may be some hesitation from certain patient populations regarding the use of these devices, specifically older patients who may not engage with technology. Martin and colleagues conducted the MiCORE study, presented at the American Heart Association Quality of Care and Outcomes Research Scientific Sessions in April, which found that patients with a mean age of 57 years who used an intervention with a smartphone app and an Apple Watch to manage their care after STEMI or non-STEMI had lower risk for being readmitted compared with those treated with usual care. The app contains a section for patients to track medication adherence and learn more about adverse effects and indications. It also has the capability to collect information on BP and heart rate, and track weight, steps and mood.
“In our experience with the Corrie MiCORE study, we saw older sick patients engaging with technology and doing so as a critical part of their recovery all the way from the intensive care unit to home,” Martin said.
Another challenge with wearables is adherence, as sometimes patients do not wear their devices for long periods of time or forget to wear them consistently.
In addition, data generated from wearables may help patients be more effective in their efforts to be more active, for example.
“Patients can be convinced when they see objective data,” Singh said. “The biggest problem right now is they come to your clinic, you give them advice, but you’re not able to provide them real-time data from any of their wearables or implantables to help them course-correct. That will be a huge change as all of these become integrated into our workflows.”
Further research
The technology aspect of wearables is there, as it is evolving faster than our ability to understand it, but a key unmet need in this area is behavioral change.
“Simple behavioral science is where we need to make more progress because you can have all the bells and whistles and the technology, but in the end, if that person is not engaged and not using them in the way they’re supposed to, then you won’t be able to improve health,” Turakhia said.
Researchers are currently conducting the HEARTLINE study, which is a randomized controlled study to assess how the Apple Watch can detect early and diagnose AF in patients aged 65 years or older.
More research is also needed on how the data from wearable devices can be integrated into clinical practice and EHRs.
“Until now, it’s tempting to dismiss all of these devices and data as not relevant to clinical practice, but there’s an incredible opportunity here, and it’s a matter of digging deeper to find what those use cases are and developing best practices,” Parakh said.
Another area of further research can look at the accuracy of testing and the feasibility of integration within health care systems, experts said. An efficacy trial can also be conducted to possibly show improved outcomes as a result of using wearable devices.
Shifts in clinical care
Despite what is still unknown about the use of wearables in a clinical care setting, there is a great potential for self-management of patients with or at risk for CVD.
“Depending on how comfortable individuals feel, how much time they have, they can watch daily dietary intake, how much they exercise and tailor it to their daily regimen, this way they can identify what works for them best and then further discuss it with their clinician if needed, but mostly this technology can allow a significant level of independence,” Isakadze said.
This technology can also initiate the shift from transactional care to continuous care.
“It’s not just that you’re having continuous monitoring, but we’re going to have continuous ways to interact and touch the health care system,” Turakhia said.
More areas of focus must be considered such as who should monitor the wealth of information and when should clinicians act on it, experts said. In addition, more thought must be put into how health care providers can integrate the assessment of this information into their daily practice, whether it be through AI, for example.
“My hope is that ultimately this is going to greatly improve clinician joy in medicine and allow us as clinicians to feel more effective because our impact won’t just be that brief time that we saw the patient in the hospital or in clinic,” Martin said. “Now we’ll be working in a more robust support system and delivery model for our patients and will be able to work with them more closely over time. Care is something that needs to happen consistently over time, not just every 6 months.” – by Darlene Dobkowski
- References:
- American Heart Association. www.heart.org/en/news/2018/08/21/google-just-launched-heart-points-here-are-5-things-you-need-to-know. Accessed July 22, 2019.
- Falter M, et al. JMIR Mhealth Uhealth. 2019;doi:10.2196/11889.
- HEARTLINE Study. Available at www.heartline.com. Accessed July 3, 2019.
- Marvel FA, et al. Young Investigator Award Semi-Finalists. Presented at: AHA Quality of Care and Outcomes Research Scientific Sessions; April 5-6, 2019; Arlington, Va.
- Nelson BW, et al. JMIR Mhealth Uhealth. 2019;doi:10.2196/10828.
- Turakhia MP, et al. Joint American College of Cardiology and Journal of American College of Cardiology Late-Breaking Clinical Trials. Presented at: American College of Cardiology Scientific Session; March 16-18, 2019; New Orleans.
- For more information:
- Nino Isakadze, MD, can be reached at nisakad1@jhmi.edu; Twitter: ninoisakadze.
- Seth S. Martin, MD, MHS, FACC, FAHA, FASPC, can be reached at smart100@jhmi.edu; Twitter: @sethshaymartin.
- Kapil Parakh, MD, MPH, PhD, can be reached at kparakh@google.com; Twitter: @kapil_parakh.
- Jagmeet P. Singh, MD, DPhil, can be reached at jsingh@mgh.harvard.edu; Twitter: @jagsinghmd.
- Mintu P. Turakhia, MD, MAS, can be reached at mintu@stanford.edu; Twitter: @leftbundle.
Disclosures: The Apple Heart Study was funded by Apple. Isakadze reports no relevant financial disclosures. Martin reports he receives research support from the Aetna Foundation, the American Heart Association, Apple, Google, iHealth, the Maryland Innovation Initiative, Nokia and the NIH, and is a founder of and holds equity in Corrie Health. Parakh reports he is an employee of Google. Singh reports he consults for Abbott, Biotronik, Boston Scientific, Impulse Dynamics, LivaNova, Medtronic and Toray. Turakhia reports he is the co-principal investigator for the Apple Heart Study, holds equity in AliveCor and consults for Abbott, Biotronik and Medtronic.
Collapse
- American Heart Association.www.heart.org/en/news/2018/08/21/google-just-launched-heart-points-here-are-5-things-you-need-to-know. Accessed July 22, 2019.
- Falter M, et al. JMIR Mhealth Uhealth. 2019;doi:10.2196/11889.
- HEARTLINE Study. Available atwww.heartline.com. Accessed July 3, 2019.
- Marvel FA, et al. Young Investigator Award Semi-Finalists. Presented at: AHA Quality of Care and Outcomes Research Scientific Sessions; April 5-6, 2019; Arlington, Va.
- Nelson BW, et al. JMIR Mhealth Uhealth. 2019;doi:10.2196/10828.
- Turakhia MP, et al. Joint American College of Cardiology and Journal of American College of Cardiology Late-Breaking Clinical Trials. Presented at: American College of Cardiology Scientific Session; March 16-18, 2019; New Orleans.
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