Rick Snyder, MD, is board certified in
Cardiovascular Disease, Interventional
Cardiology, and Advanced Heart Failure
and Transplant Cardiology, and has
practiced at Medical City Dallas Hospital
since 1996. He is a DCMS past president
and serves on the TMA Board of Trustees.
November 2018 Dallas Medical Journal 23
Series 4 continuously will monitor your HR via the optical HR
sensor, and analyze the rate for irregularities and abnormal rates
suggestive of afib. If your optical HR exceeds any of the preset
parameters, you will be alerted about the possible presence of
afib and prompted to get an ECG tracing on the watch. (See
photos 5 and 6.)
So, in effect, you have a device that continuously monitors for
afib via use of the combined biometric technologies. The FDA
approved this software — Irregular Rhythm Notification Feature
— only in September 2018 as a Class II device for over-thecounter
use. FDA approval was made possible by a study Apple
conducted with Stanford University called the Apple Heart
Study. The study included 588 people (half were healthy, half
had afib), and identified with 98% accuracy the patients who
had afib, and with 99% accuracy the patients who had healthy
heart rates. Cardiologists also were able to read 90% of the total
measurements; the other 10% were unreadable. The ECG app is
not yet out, so I haven’t been able to test this.
CONCERNS WITH WEARABLES
For years cardiologists and patients have asked for an
ambulatory method to monitor patients who have chronic
diseases such as afib. The real question is whether we should be
careful what we ask for. Ambulatory ECG (AECG) monitoring
clearly provides real and powerful benefits about populationwide
AECG monitoring and subsequent mass screening. Benefits
to society could be enormous, with the promise to use biometric
big data to advance epidemiologic knowledge of disease.
But accompanying the benefits are worrisome issues of bias,
privacy and data ownership. For all the hype, these devices still
have not proven that they improve outcomes. Mobile cardiac
monitoring devices offer big promise to improve the quality of
the management of cardiac-related diseases and lower costs. But
they just as likely could exacerbate cost by vastly exploding the
noise relative to the signal that they are purported to refine.
Use of this test in an asymptomatic population typically opens
a statistical Pandora’s box in terms of false-positive results.
Testing in such low-risk groups tends to lead to more false
positives than true positives. For this reason, I limit the use of
these mobile ECG devices to patients with established rhythm
conditions such as paroxysmal afib or SVT for chronic disease
monitoring and management only. These patients tend to be
educated about their disease and can participate in monitoring
their condition. A patient with recurrent symptoms can get an
immediate wearable ECG tracing, which, if normal, can be
reassuring to them. Alternatively, a tracing that shows a reemergence
of afib can lead to appropriate therapy. I worry that
in the hands of the average layperson who is asymptomatic
with no diagnosis, self-administered ECG tracings without the
focused instruction, guidance and caution from supervising
clinicians could significantly expand the need for more indepth,
unnecessary and expensive follow-up tests. False-
positive readings from misinterpreted rhythms due to imperfect
algorithms or excessive artifact could lead to misdiagnosis,
excessive anxiety and unnecessary ED visits out of an abundance
of caution — or worse, calls to covering physicians in the middle
of the night! I have received multiple calls to my office in the
last few months from anxiety-filled patients who had purchased
a Kardia ECG device on their own and were alarmed by the
tracings they had recorded. At least in the short term, this new
technology could unleash a tidal wave of self-referrals from
well-meaning users who are concerned that the common and
ubiquitous PAC is a malignant arrhythmia and a sign of a serious
condition. In the study I reported on earlier, the KB algorithm
was most accurate in the setting of physician oversight. Thus,
in regard to the arrival of these over-the-counter wearable AI
biomonitors, we must tread cautiously. As one commentator said
in regard to the emergence of these devices: A smart device can
be smart only if used intelligently. DMJ
Photo 5. The new
Apple watch uses
the optical HR
monitor feature
in the background
to screen for
abnormalities
suggestive of Afib.
Photo 6. Example of how to take an ECG on the new Series 4 by
touching your opposite hand to the dial.