Summary
Digital diagnostics are making progress in the field of atrial fibrillation
Prominent solutions like iRhythm’s Zio Service and BardyDx’s Carnation Ambulatory Monitor (CAM) Patch provide more convenient mini-heart monitors, time-saving analysis of cardiac results for doctors. Smartphone apps like Fibricheck and wearables, which use photoplethysmography (PPG) sensors to measure heart rate, are also in play.
Smartphone apps and wearables are making good progress but diagnoses with such technologies require additional confirmation with gold standard solutions.
The hope is that wearables/smartphone solutions can one day act as a form of pre-screening. Since AF patients are older, they may not be as tech-savvy but the feeling of physical irregularities might incentivise them to pick up convenient solutions. More importantly, new solutions should not miss out cases lest patients get lulled into false security.
Atrial fibrillation (AF) is the most common type of cardiac arrhythmia affecting over 11 million people in Europe. Patients often suffer from palpitations, fatigue, shortness of breath and reduced quality of life as a result. If untreated, AF can lead to complications like stroke or heart attack.
Whilst traditionally diagnosed by an electrocardiogram (ECG), the condition is difficult to detect as irregular heartbeat can occur at anytime, anywhere, not only when checks are conducted in the doctor’s office.
Doctors may prescribe a second device called a Holter Monitor, which patients wear for 24-72 hours or up to 7 days in hopes of capturing signs of the elusive disease. But the device cannot get wet; it also involves sticky electrodes which may cause skin irritation for some.
The disease area has thus attracted the attention from an array of innovative digital health companies.
Some early winners have already been reimbursed by US Payers including:
Zio Service by iRhythm
Compared with bulkier Holter monitors, iRhythm’s Zio XT is a 3-inch water-resistant patch worn close to the heart which enables uninterrupted monitoring for up to 14 days.
The Zio Service also includes a report with a summary of cardiac data, analysed by machine-learning algorithms that point out spates of cardiac arrhythmia. This saves time for clinicians who would have to otherwise comb through the data manually.
Backed by a strong evidence base, Zio Service is currently reimbursed by the US Centers for Medicare and Medicaid (CMS) and is undergoing NICE evaluation.
Carnation Ambulatory Monitor (CAM) Patch by BardyDx
BardyDx’s CAM Patch provides a similar solution to the Zio Service but its mini cardiac monitor uses a special P-wave technology to capture cardiac signals.
A recent study showed that BardyDx’s CAM Patch identified 40% more arrhythmias but resulted in better clinical decision-making in only 41% of patients compared with the ZioXT
BardyDx’s CAM Patch can be billed under CMS codes for Holter Monitoring and Extended Cardiac Monitoring.
Besides the iRhythm’s Zio Service and BardyDx’s CAM Patch, which are essentially smarter, more comfortable heart monitors, smartphone-based solutions are also worth mentioning. Many, such as Fibricheck and the Apple watch, utilise photoplethysmography (PPG) sensors which already exist in smart devices to detect changes in tissue blood volume that result from peripheral pulses, which also indicates heart rate.
Smartphone-based solutions
FibriCheck by Qompium
FibriCheck is a patient-facing app that requires patients to place their fingers over the smartphone camera for one minute to measure their heart rhythm. It uses PPG sensors to determine heart rhythm of users.
The solution is backed by clinical studies and is more popular in Europe. It also includes a Smart Watch app that detects both silent and intermittent AF.
Apple Watch
Tech giant Apple caught the attention of many when it announced results of its Apple Watch Heart Study with over 419,000 users involved.
The Apple Watch Series 4 and above is armed with both PPG sensors and an ECG app.
In the Apple Watch Heart Study, the device used optical sensors to detect changes in pulse, which might indicate irregular heartbeat. In the study, detection of 5-6 irregular pulse events in 48 hours triggered a notification. Patients were then sent an ECG patch to wear, in order to confirm the diagnosis.
AF was detected in only 34% of participants received a notification and wore the ECG patch. During ECG patch monitoring, participants’ Apple Watches continued to monitor pulse irregularities. If a participant had an irregular pulse detected, 84% of the time this was confirmed to be atrial fibrillation on the simultaneous ECG patch.
Other well-known solutions include AliveCor’s KardiaMobile, an $89 solution requiring an additional small strip device and a phone app that enables patients to record and review electrocardiograms (ECG's) anywhere, anytime.
Interestingly, both iRhythm’s Zio Service and BardyDx’s CAM Patch provide more convenient alternatives to remote heart monitoring worn close to the heart, accompanied by time-saving analysis reports.
Backed by evidence, this is a strong value proposition that clinicians trust and may be familiar with. In contrast, other solutions that utilise commonplace smartphones and watches, may rely on technology that doctors are less familiar with (e.g. not worn over the heart, but using smartphone-based cameras or detection of the human pulse from a watch).
However, the hope is that one day, commonplace mobile/wearable technology may be used as reliable pre-screening tools to identify patients in need of more costly ECG tests, hence saving costs.
First, mobile/wearable technology itself needs to reliably identify AF, and more importantly, not miss out any cases which can be subsequently confirmed by gold standard tests. The Apple Watch trial, for example, did not provide any false-negative cases, leaving open questions.
Second, most AF patients tend to be over 65 and your typical grandparent tends to be less tech-savvy. However, the feeling of cardiac abnormality might also be a strong incentive to try out convenient solutions.
Still, digital health solutions are helping to re-shape the AF space. So far, they have provided earlier detection whilst saving time for doctors and reducing discomfort for patients. There is still room for improvement but meanwhile, progress is also worth celebrating.
This article provides a summary of a few key solutions in Afib and is not intended to be a comprehensive scientific review of solutions in the disease area.
Join us in the second part of our 2-part series on AF, where we discuss AF risk scores, another area of progress in AF diagnostics.