Medtronic’s Dr. Alan Cheng on Consumer vs. Medical Heart Monitors

The U.S. Department of Health and Human Services (HHS) is preparing a campaign to promote wearable health devices. As a result, many experts are urging Americans to educate themselves about the difference between consumer wearables and medical-grade devices.

With the passing of atrial fibrillation (AFib) awareness month, an important question comes to light: Can consumer wearables like smartwatches really spot serious conditions like AFib?

For example, the Apple Watch uses irregular rhythm notifications and its ECG app to detect signs of AFib. When the watch detects an irregular rhythm, it prompts the user to contact a doctor for professional evaluation and diagnosis. The device itself isn’t a screening tool or a diagnostic device and requires a cardiologist’s review to confirm an AFib diagnosis. It shouldn’t be used to make changes to medications or detect heart attacks or strokes.

Wearables have their utility in consumer health—they let patients capture more real-time heart health data than ever before. But a recent study shows that medical-grade technology is still needed for doctors to have an accurate, reliable way to spot and manage cardiac conditions like AFib.

The first-of-its-kind, app-based DEFINE AFib clinical study of nearly 1,000 people found that a small medical-grade Medtronic heart monitor implanted under the skin detected far more episodes of AFib than the wearable did. However, this doesn’t mean people should get rid of their wearables.

Alan Cheng, MD, electrophysiologist and chief medical officer of the Cardiac Rhythm Management business at Medtronic spoke to Medical Product Outsourcing on this topic, hoping to illuminate the challenges with AFib diagnosis and the roles consumer wearables and medical-grade monitoring can play in cardiac health.

Sam Brusco: What are the current unmet clinical needs for AFib diagnosis?

Alan Cheng, MD: The most important unmet clinical need is detecting AFib so a diagnosis can be made. AFib is one of the most common arrhythmias experienced in the United States, with an estimated 12 million Americans being diagnosed by 2030. The majority of people experience symptoms like generalized fatigue, shortness of breath, or a flutter or racing heartbeat, and are diagnosed either at a doctor’s appointment or through some form of cardiac monitoring. Detecting AFib is challenging because episodes can happen infrequently and sometimes without any symptoms.

AFib is a progressive disease, and when left untreated or undiagnosed, it can lead to larger medical problems for patients. For example, studies have shown that people with untreated AFib are five times more likely to have a stroke and an increased chance of developing heart failure.¹ Additionally, approximately one in four stroke survivors will experience another stroke within five years.² Since AFib is known to increase the risk for strokes, detection is key so preventative measures can be taken.

Brusco: How does the LINQ II ICM resolve those unmet needs?

Dr. Cheng: The LINQ family of insertable cardiac monitors (ICM) are medical grade monitors that can continuously watch the heart’s rhythm and record any episodes that may be suggestive of AFib. People with unexplained fainting (syncope), palpitations without a clear diagnosis, require AFib management, and those who have had a cryptogenic stroke with an unclear cause may be good candidates for an ICM.

The LINQ ICM is placed just under the skin in the chest during a minimally invasive device procedure. The device is about one-third the size of a AAA battery and provides continuous, uninterrupted heart rhythm monitoring for up to several years if needed. Often, ICMs are recommended if a shorter-term external cardiac monitor, like a patch or Holter monitor, do not yield a diagnosis. We introduced the first ICM to the market in 1998 and designed these devices for any patient at risk for developing arrhythmias. Now 80% smaller and more powerful with artificial intelligence capabilities, Medtronic ICMs have been implanted in more than 2 million patients worldwide, including pediatric patients.

We’re continually learning, and clinical research has shown that long-term heart monitoring with an ICM after a stroke significantly increases the chances of detecting atrial fibrillation. In the STROKE-AF study, stroke patients had a 10-fold increase in AF detection with the Reveal LINQ ICM at three years compared to patients who did not receive continuous, long-term monitoring.³ For stroke patients, the impact of a second stroke is often more severe due to the additional damage to the brain. That’s why it is important that stroke patients have the right monitoring in place to inform their treatment plan.

Brusco: How do consumer wearables differ from medical-grade monitors?

Dr. Cheng: Consumer wearables like smartwatches continue to grow in popularity and we know that many people rely on consumer wearables to track their overall health activity. While these devices may offer valuable insights into heart health trends, they often lack the precision and diagnostic capabilities of medical-grade devices. When it comes to conditions like AFib, not all monitoring options provide the same level of accuracy and reliability, and consumer wearables may be better suited as a supplement rather than a substitute for professional monitoring. The issue with these is that heart rhythm abnormalities can be intermittent, sometimes occurring months apart, which requires continuous, long-term monitoring with symptom marking capabilities. Also, patient compliance, like taking the wearable off to shower, exercise or charge the device, is an issue for these shorter-term external monitors.

While wearables can be helpful tools to potentially detect an abnormal heart rhythm, there is a gap in the level of detection and ability to monitor compared to medical-grade ICMs. Recent data from the DEFINE AFib Clinical Study—an app-based study—found that consumer-grade wearable technology showed limited sensitivity in detecting AFib compared to the medical-grade LINQ ICM. Consumer wearables depend on how long the user wears the device, only capturing some of the AFib episodes that happen while being worn, compared to ICMs, which monitor continuously with a high level of accuracy and reliability for up to several years.

The study showed that 40% of AFib episodes occurred while the wearable was not being worn. This is largely due to the fact that AFib episodes can often occur at night, while wearables are often taken off to recharge. And when worn, the wearable was only able to detect about a quarter of AFib incidences that lasted 75 minutes or more, when compared to an ICM.⁴ The differences are noteworthy.

Brusco: Is it useful to pair consumer wearables with medical-grade monitors to spot AFib?

Dr. Cheng: There is a place for both wearable and medical-grade monitors in today’s world, but it’s important to keep in mind they serve different purposes. Wearable devices provide general overall health data that can inform a healthy individual on wellness and healthy living habits. Medical-grade monitors are designed to manage patients with a medical condition like AFib, which, if left unchecked, could result in serious medical consequences.

Brusco: Where else (if anywhere) in electrophysiology might be useful to use consumer wearables in tandem with medical-grade monitors?

Dr. Cheng: Consumer wearables can provide helpful insights into overall health. Providing information on sleep cycles, for example, is one way that wearables can complement medical-grade technology. However, we shouldn’t rely on consumer wearables to diagnose or manage serious heart conditions like AFib. If a consumer wearable detects an irregular heart rhythm, it is crucial to see a healthcare provider immediately to understand the best diagnosis and treatment plan.

Despite these limitations, consumer wearables can co-exist with medical-grade cardiac monitors and can provide an early signature that atrial fibrillation is present—particularly episodes that are longer in duration that may be easier to catch. Alerts from a wearable may provide a warning for patients so they can go to the doctor and be properly diagnosed by a clinic team.

References
¹ https://www.ahajournals.org/doi/10.1161/strokeaha.115.012004
² Mohan KM, Wolfe CD, Rudd AG, Heuschmann PU, Kolominsky-Rabas PL, Grieve AP. Risk and cumulative risk of stroke recurrence: a systematic review and meta-analysis. Stroke. 2011;42(5):1489–1494. doi:10.1161/STROKEAHA.110.602615
³ Bernstein RA et al. Atrial Fibrillation In Patients With Stroke Attributed to Large- or Small-Vessel Disease: 3-Year Results From the STROKE AF
⁴ https://academic.oup.com/eurheartj/article/45/Supplement_1/ehae666.3538/7839071