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\begin{document}

\title{The Practical Utility of the Postal Service in Delivering a
Self-Wearable, Long-Term ECG Monitoring Device for Outpatient Care}



\author[1]{Mitsuru Takami}%
\author[1]{Koji Fukuzawa}%
\author[1]{kunihiko kiuchi}%
\author[1]{makoto takemoto}%
\author[2]{Toshihiro Nakamura}%
\author[1]{jun sakai}%
\author[1]{atsusuke yatomi}%
\author[1]{Kazutaka  Nakasone}%
\author[1]{Yusuke Sonoda}%
\author[1]{Kyoko Yamamoto}%
\author[1]{Hiroyuki Takahara}%
\author[3]{Yuya Suzuki}%
\author[4]{Kenichi Tani}%
\author[1]{Ken-ichi Hirata}%
\affil[1]{Kobe University Graduate School of Medicine}%
\affil[2]{Kobe University}%
\affil[3]{Akashi Medical Center}%
\affil[4]{Kobe University Hospital}%


\vspace{-1em}



  
  \date{May 23, 2024}


\begingroup
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\selectlanguage{english}
\begin{abstract}
Introduction: In the COVID-19 era, demand is growing for remote ECG
monitoring systems with less or no in-person contact. However, the
practical usage of wearable ECG devices has been little studied in
Japan. This study aimed to report our initial experience of using the
postal system in the delivery of the self-wearable ECG device (Duranta)
and long-term ECG monitoring in outpatient care. Methods:\begin{CJK}{UTF8}{gbsn}　　 \end{CJK}\selectlanguage{english}The
Duranta is small, light (35 g), and easy to attach to the chest with two
patch electrodes. Real-time ECG data were automatically transmitted to a
cloud server via iPhones. The devices were packed in prepaid envelopes
that could be put in any postbox for delivery between the hospital and
patients' homes. Results: Twenty-five patients (61 \selectlanguage{ngerman}± 17 years) were
enrolled. The median distance to the hospital from the patients' homes
was 10 km (range: 1.1--183). The patients had no difficulties with
either the postal delivery or wearing the ECG devices. A total of 57
hours (range: 20--179) of ECG monitoring per patient was performed, and
the data were successfully transmitted to the hospital. The median
percentage of noise/artifact burden during the ECG monitoring was 0.9\%.
Arrhythmic events were observed in 8 patients. Most patients were
satisfied with the ECG system and delivery via the postal service.
Conclusion: The use of a postal delivery of a wearable ECG device could
work in clinical practice with to achieve less or no in-person contact.
This system can be applicable for telehealth, home care, and arrhythmia
screening.%
\end{abstract}\selectlanguage{ngerman}%



\sloppy


\textbf{Introduction:}

In the COVID-19 era, demand is growing for remote ECG monitoring systems
with less or no in-person contact. However, the practical usage of
wearable ECG devices has been little studied in Japan. This study aimed
to report our initial experience of using the postal system in the
delivery of the self-wearable ECG device (Duranta) and long-term ECG
monitoring in outpatient care.

\begin{CJK}{UTF8}{gbsn}\textbf{Methods:　　}

\end{CJK}\selectlanguage{english}The Duranta is small, light (35 g), and easy to attach to the chest with
two patch electrodes. Real-time ECG data were automatically transmitted
to a cloud server via iPhones. The devices were packed in prepaid
envelopes that could be put in any postbox for delivery between the
hospital and patients' homes.

\textbf{Results:}

Twenty-five patients (61 \selectlanguage{ngerman}± 17 years) were enrolled. The median distance
to the hospital from the patients' homes was 10 km (range: 1.1--183).
The patients had no difficulties with either the postal delivery or
wearing the ECG devices. A total of 57 hours (range: 20--179) of ECG
monitoring per patient was performed, and the data were successfully
transmitted to the hospital. The median percentage of noise/artifact
burden during the ECG monitoring was 0.9\%. Arrhythmic events were
observed in 8 patients. Most patients were satisfied with the ECG system
and delivery via the postal service.

\textbf{Conclusion:}

The use of a postal delivery of a wearable ECG device could work in
clinical practice with to achieve less or no in-person contact. This
system can be applicable for telehealth, home care, and arrhythmia
screening.

\textbf{Key Words}

remote ECG monitoring, Holter ECG, postal delivery service, COVID-19

\textbf{Introduction}

The spread of coronavirus disease 2019 (COVID-19) has seriously affected
the medical system worldwide. In addition to caring for patients
suffering from COVID-19, medical staff have faced difficulties in the
outpatient care of non-COVID-19 patients. Some hospitals have
temporarily closed their outpatient clinics because of COVID-19
clusters, and patients with chronic disease have tended to avoid going
to hospital for fear of contracting the disease. Avoiding regular
consultations at hospitals/clinics might result in the worsening of
chronic conditions. Currently, there is a growing demand on the part of
patients and health care workers for remote monitoring
systems\textsuperscript{1, 2} that use digital technologies to collect
medical data from individuals, thus eliminating the need to visit a
medical facility in person.

A patch-type wireless, real-time electrocardiogram (ECG) monitor
(Duranta; ZAIKEN Co., Ltd. Tokyo, Japan) has been approved and already
used as a Holter ECG device in Japan.\textsuperscript{3, 4}
Conventionally, patients visit the hospital to have the Duranta
attached. After the ECG monitoring, the patients return to the hospital
to remove the device. The device is small (35 g) and attaches easily to
the chest using two electrode patches. We therefore thought that
patients could attach the device themselves and that the device could be
sent via the postal service between the hospital and the patients'
homes. This novel usage of the Duranta would allow patients to share the
telemetry ECG data with their doctors without visiting the hospital or
visiting less often. Here, we report the initial experience of using the
small wireless ECG monitoring device and the utility of delivery via the
postal service in outpatient care in Japan.

\textbf{Methods}

We retrospectively analyzed the data of patients who underwent long-term
ECG monitoring at Kobe University Hospital between August and December
2020 with the Duranta device that was delivered via the postal service.
The data including patient characteristics, the method of delivery, ECG
monitoring duration, detection of arrhythmia, and any noises or signal
interruption during the ECG monitoring were analyzed. In addition, we
surveyed the patients to quantify their satisfaction regarding the
self-wearable ECG monitoring device delivered via the postal service.
The protocol for this research project was approved by the Ethics
Committee of Kobe University Hospital (Approval no. B200276).

\textbf{ECG devices}

The details of the wireless, patch-type ECG monitoring device (Duranta;
medical device certificate number in Japan: 226AIBZX00055000) were
previously reported.\textsuperscript{3, 4} The Duranta device is small
(78.4 mm wide × 35.1 mm deep × 14.7 mm thick), light (35 g), and easy to
attach to the chest via two patch electrodes (\textbf{Figures 1A, 1B} ).
The battery lasts up to seven consecutive days without charging. The
patients detach the device to bathe and reattach it afterwards. The ECG
data is automatically transmitted to the cloud server via a dedicated
iPhone. The patients can see their own ECG on the iPhone. Medical staff
can access the cloud server using a personal ID/password and can see the
real-time ECG of the patients on an iPad and download the ECG data to a
computer in the hospital (\textbf{Figure 1C} ). The patients' personal
information was not input in the ECG devices (the Duranta and the
iPhone); therefore, there was no risk of personal date leakage during
delivery of the ECG devices.

\textbf{Postal Delivery Method}

\textbf{Figure 1D} shows how the ECG devices are delivered. The Duranta,
iPhone, battery charger, and electrode patches were surrounded by
cushioning materials and packed in a small paper box. The box and
written instructions for the ECG device were put in a pre-paid envelope
(Letter Pack Light, Japan Post). The Letter Pack Light format can be
used to send items that weigh up to 4 kg with thickness up to 3 cm. The
price is 370 yen (\selectlanguage{english}[?]\$3.50) throughout Japan, including tracking and
confirmation of delivery. When the ECG devices were sent from the
hospital to patients' homes, the package included a return envelope. The
Letter Pack can be put in any postbox in Japan. Usually, the Letter Pack
arrived at their destinations in 1--2 days.

The postal delivery of the ECG devices was performed in two different
ways called the ``One way'' and the ``Two way'' (\textbf{Figure 2} ).
``One way'' indicates that the patients attached the ECG devices when
they visited a outpatient clinic. After long-term ECG monitoring at
home, they sent the devices back to the hospital by post. ``Two way''
indicates that medical staff sent the ECG devices to patients' homes by
post on a prearranged day and the patients attached the device at home.
After long-term ECG monitoring, the patients sent the devices back to
the hospital by post. All ECG devices and iPhones were sterilized with
an 80\% ethyl alcohol swab after they were returned to the hospital. The
electrode patches were disposable.

\textbf{Statistical Analysis}

Continuous variables were examined using the Shapiro--Wilk test for
normality. For continuous variables of normal distribution, the data
were presented as means~+-~standard deviation (SD). For the non-normal
distribution, the data were presented as medians (ranges). Spearman's
rank correlation was used to investigate the relationship between the
percentage of noise duration and the actual monitoring time. The
p-values are two-sided. A p-value of \textless{} 0.05 was considered to
indicate statistical significance. All statistics were calculated using
R statistical software (version 2.13.0, R Foundation for Statistical
Computing, Vienna, Austria).

\textbf{Results}

\textbf{Patients characteristics and the postal delivery}

A total of 25 patients (63+-16 years, 17 male) underwent long-term ECG
monitoring using the Duranta delivered via the postal
service.\textbf{Table 1} shows the patient characteristics. The purpose
of the long-term ECG monitoring was to investigate unknown palpitations
(n = 3) and unknown syncope (n = 3), to follow up the tachyarrhythmias
after the catheter ablation (n = 18), and to follow up the bradycardia
(n = 1). Three of the 25 patients (12\%) needed assistance in daily
life. \textbf{Figure 3} shows the distribution map of the patients
enrolled in the study. The median distance to the Kobe University
Hospital from patients' homes was 10 km (range: 1.1--183 km).

Of the patients, 13 used the ``One way'' service and 12 used the ``Two
way'' service. All the ECG devices arrived at the patients' homes or the
hospital on the scheduled day. There were no mechanical issues with the
ECG devices during the postal delivery or during the monitoring.

\textbf{ECG monitoring duration and arrhythmia detection}

The patients or their families had no difficulty attaching the ECG
device. A median 57 hours (range: 20--179 hours) of ECG monitoring per
patient was performed. \textbf{Figure 4} shows the relationship between
the prescheduled ECG monitoring duration and the actual ECG monitoring
duration for each patient. Monitoring the ECG was performed as planned
in most cases. \textbf{Figure 5} shows a representative case of ECG
monitoring. By utilizing the postal delivery service, this patient did
not need to visit the hospital to undergo the long-term ECG examination.
Arrhythmic events were detected in 8 of the 25 patients (32\%), atrial
fibrillation (AF) in 5 patients, atrial tachycardia in 2 patients, and
frequent premature ventricular contractions in 1 patient.

\textbf{Noises and interruption during ECG monitoring}

The electromyographic noise, the electrode motion artifacts, and the
temporary interruption of ECG signals were observed (\textbf{Figure 6A}
). The median percentage of the total duration of noise signals and
temporary interruption during the whole monitoring duration was 0.9\%
(range 0.1--4.5\%). \textbf{Figure 6B} shows the relationship between
the monitoring duration and the percentage of the noises/interruption of
the monitoring. The monitoring duration did not have a significant
correlation with the duration of the noises and the ECG signal
interruption.

\textbf{Patient survey}

\textbf{Figure 7} shows the results of the patient survey regarding the
long-term ECG monitoring and the postal delivery service. Most patients
had no difficulty sending the devices by post and no difficulty putting
on or taking off the ECG device by themselves. Most patients thought the
postal delivery of ECG devices could reduce patient burden in terms of
going to the hospital.

Of the patients, 12 (48\%) felt itchiness or irritation at the sites of
the electrode patches during the ECG monitoring but could continue to
undergo monitoring by slightly changing the location of the patches on
the chest. Seventeen of the 25 patients had experienced conventional
Holter ECG monitoring before. Sixteen of these 17 patients (94\%)
preferred the self-wearable ECG monitoring and the postal delivery
service over the conventional Holter ECG monitoring because the Duranta
device is wireless, smaller, and lighter than the conventional Holter
ECG device (n = 9) and it was extremely convenient to use the postal
service to return the devices rather than having to go to the hospital
(n = 7).

\textbf{Discussion}

There has been strong demand for remote monitoring devices to gather
data with no or less in-person contact.\textsuperscript{1} Various types
of wearable monitoring devices with higher accuracy, specificity, and
sensitivity have been invented.\textsuperscript{5} However, Ferguson et
al.\textsuperscript{6} state there are disadvantages regarding the
adoption of wearable devices for older patients; these relate to the
design of the devices, appropriate and timely feedback,
user-friendliness, and cost. In the present study, we provide evidence
of high patient acceptance of self-wearing an ECG device and sending the
device by post. The Japanese postal service is known for its reliable,
fast, and high-quality service that is able to deliver the ECG devices
in 1 or 2 days with no difficulty. There are approximately 180,000
postboxes in Japan; therefore, there was no need for patients to visit
the hospital to put on or take off the ECG device. Instead, the patients
just put the ECG devices in the nearest postbox to return them to the
hospital, thus reducing patient burden. In terms of the cost, patients
did not need to pay an additional charge for postal delivery. The cost
of postal delivery was only around \$3.50 everywhere in Japan. All ECG
devices were sterilized and could be used for the next examination. The
medical cost performance of the self-wearable ECG monitoring device
delivered via the postal service would be high for both patients and
medical facilities.

Patients of different ages (range: 15--82 years old) were enrolled in
the present study. Some had dementia and needed partial assistance in
daily life. However, there was no difficulty with wearing the ECG
devices or sending them back to the hospital by post, which suggests
that this method would be applicable in other clinical practices.

\textbf{1) Telehealth}

Since the emergence of the COVID-19 pandemic, telehealth and online
consultations have been gaining attention worldwide. The market for
telehealth continues to grow rapidly.\textsuperscript{7} However, one of
the shortcomings of telehealth is the lack of information about the body
during the online appointment. With the postal delivery of ECG devices
before the online consultation, the doctor could see the real-time ECG
during the online consultation.

\textbf{2) Screening and early detection of atrial fibrillation}

Asymptomatic AF has been independently associated with an increased risk
of stroke and mortality compared with symptomatic
AF.\textsuperscript{8}A recent study shows that early rhythm-control
therapy for AF is associated with a lower risk of cardiovascular
outcomes than the usual rate-control therapy.\textsuperscript{9}
Therefore, a recent guideline has recommended opportunistic screening
for AF by pulse taking or ECG rhythm strip in patients
\textgreater{}\_65.\textsuperscript{10} The postal delivery of the ECG
devices and the long-term ECG screening would be applicable as a tool
for AF screening in medical checkups in high-risk populations.

\textbf{3) Home care of elderly patients}

Japan is the world's most aged country. The long-term care insurance
system in Japan was started in 2000, and many elderly patients have
since received home care services. Some elderly patients have difficulty
visiting medical facilities on a regular basis due to low activity of
daily living. In such cases, the family doctor can send an ECG device by
post, and the family or home care worker can attach the device to the
patient's chest. If the ECG shows any abnormalities, the family doctor
would share the ECG data with a cardiologist and ask them how to deal
with the arrythmia. This would be particularly useful in areas in Japan
where there is poor access to medical facilities.

\textbf{Points to be improved}

The actual monitoring duration did not reach the prescheduled duration
in some patients. The percentage of noises or interruption during ECG
monitoring and actual monitoring time did not show any significant
correlation, which suggests that the ECG monitoring quality largely
differed among the patients. To improve the monitoring quality, precise
oral and written instructions for patients on how to use the
self-wearing ECG device should be provided for patients depending on age
and level of understanding. Approximately 48\% of patients felt
itchiness or irritation at the sites of the electrode patches during the
long-term ECG monitoring. The adhesive material of the electrode patches
should be improved.

\textbf{Limitations}

First, this study was a retrospective study, and the number of the
patients was small. A further prospective study will be needed to
establish the convenience and efficacy of the ECG monitoring system
delivered via the postal service compared with conventional ECG
monitoring methods. Second, patients with severe dementia and bedridden
patients were not enrolled in the present study. Therefore, the results
may not be generalizable to some other patient populations.

\textbf{Conclusion}

Wearable ECG devices delivered via the postal service can safely monitor
and record long-term ECG data in patients with no or less in-person
contact. The patients were highly satisfied with the system, as it
reduced the patient burden of visiting the hospital. This system would
be applicable in other patient care, such as telehealth, home care, and
arrhythmia screening.

\textbf{Acknowledgement}

None

\textbf{References}

1. Varma N, Marrouche NF, Aguinaga L, et al.
HRS/EHRA/APHRS/LAHRS/ACC/AHA worldwide practice update for telehealth
and arrhythmia monitoring during and after a pandemic. \emph{Heart
Rhythm} . 2020;17:e255-e268.

2. Varma N, Cygankiewicz I, Turakhia MP, et al. 2021
ISHNE/HRS/EHRA/APHRS Expert Collaborative Statement on mHealth in
Arrhythmia Management: Digital Medical Tools for Heart Rhythm
Professionals: From the International Society for Holter and Noninvasive
Electrocardiology/Heart Rhythm Society/European Heart Rhythm
Association/Asia-Pacific Heart Rhythm Society. \emph{Circ Arrhythm
Electrophysiol} . 2021:CIRCEP120009204.

3. Yoshizawa MO, H. Nunokawa, K. Taniuchi, et al. A
Tele-Electrocardiographic Monitoring System for Patients with Chronic
Diseases at Home. \emph{Austin Emergency Medicine} . 2016;2:1-4.

4. Akiyama H, Nukui S, Araga T, et al. Utility of Duranta, a wireless
patch-type electrocardiographic monitoring system developed in Japan, in
detecting covert atrial fibrillation in patients with cryptogenic
stroke: A case report. \emph{Medicine (Baltimore)} . 2017;96:e5995.

5. Dagher L, Shi H, Zhao Y, Marrouche NF. Wearables in cardiology: Here
to stay. \emph{Heart Rhythm} . 2020;17:889-895.

6. Ferguson C, Inglis SC, Breen PP, et al. Clinician Perspectives on the
Design and Application of Wearable Cardiac Technologies for Older
Adults: Qualitative Study. \emph{JMIR Aging} . 2020;3:e17299.

7. Hu PT, Hilow H, Patel D, et al. Use of virtual visits for the care of
the arrhythmia patient. \emph{Heart Rhythm} . 2020;17:1779-1783.

8. Boriani G, Laroche C, Diemberger I, et al. Asymptomatic atrial
fibrillation: clinical correlates, management, and outcomes in the
EORP-AF Pilot General Registry. \emph{Am J Med} . 2015;128:509-18 e2.

9. Kirchhof P, Camm AJ, Goette A, et al. Early Rhythm-Control Therapy in
Patients with Atrial Fibrillation. \emph{N Engl J Med} .
2020;383:1305-1316.

10. Hindricks G, Potpara T, Dagres N, et al. 2020 ESC Guidelines for the
diagnosis and management of atrial fibrillation developed in
collaboration with the European Association of Cardio-Thoracic Surgery
(EACTS). \emph{Eur Heart J} . 2020.

\textbf{Table 1.} Patient characteristics\selectlanguage{english}
\begin{longtable}[]{@{}ll@{}}
\toprule
Age* {[}range{]} (year) & 63 \selectlanguage{ngerman}± 16 {[}15-82{]}\tabularnewline
\midrule
\endhead
Male sex\textsuperscript{+} & 17 (77)\tabularnewline
BMI* & 25 \selectlanguage{ngerman}± 4\tabularnewline
Distance to the hospital {[}range{]} (km) & 10
{[}1.1-183{]}\tabularnewline
LVEF* (\%) & 60 \selectlanguage{ngerman}± 8\tabularnewline
NYHA \textsuperscript{+} I & 20 (80)\tabularnewline
II & 4 (16)\tabularnewline
III & 1 (4)\tabularnewline
IV & 0 (0)\tabularnewline
Dementia\textsuperscript{+} & 3 (12)\tabularnewline
Hypertension\textsuperscript{+} & 12 (48)\tabularnewline
Diabetes \textsuperscript{+} & 4 (16)\tabularnewline
Stroke\textsuperscript{+} & 3 (12)\tabularnewline
Coronary artery disease\textsuperscript{+} & 4 (16)\tabularnewline
Chronic kidney disease\textsuperscript{+} & 4 (16)\tabularnewline
Activities of Daily Living: &\tabularnewline
Autonomous\textsuperscript{+} & 22 (88)\tabularnewline
Needs partial assistance\textsuperscript{+} & 3 (12)\tabularnewline
Needs assistance, bedridden\textsuperscript{+} & 0 (0)\tabularnewline
Style of Living: &\tabularnewline
Living alone\textsuperscript{+} & 5 (20)\tabularnewline
Living together with family\textsuperscript{+} & 20 (80)\tabularnewline
Purpose for the long-term ECG &\tabularnewline
Unknown palpitations\textsuperscript{+} & 3 (12)\tabularnewline
Unknown presyncope\textsuperscript{+} & 3 (12)\tabularnewline
Follow-up the tachyarrhythmia after catheter ablation\textsuperscript{+}
& 18 (72)\tabularnewline
Follow-up the bradycardia\textsuperscript{+} & 1 (4)\tabularnewline
\bottomrule
\end{longtable}

*, mean\selectlanguage{ngerman}±SD; \textsuperscript{+}, n (\%); BMI, body mass index; LVEF,
left ventricular ejection fraction; NYHA, New York Heart Association
functional classification; ECG, electrocardiogram.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image1/image1}

\end{center}
\end{figure}

\textbf{Figure 1. ECG monitoring system (Duranta) and the delivery
method.} (A) The Duranta and the iPhone for transmitting ECG data. (B)
The Duranta is easy to attach to the chest via two electrode patches.
The real-time ECG data can be seen on the iPhone. (C) The doctors and
medical staff can see the ECG on an iPad and analyze the data on a
computer at the hospital. (D) Delivery method of the ECG devices. A
Duranta, an iPhone, a battery charger, and electrode patches are
surrounded by cushioning materials were packed in a small paper box (225
mm wide \selectlanguage{ngerman}× 160 mm deep × 22 mm thick). The paper box was put in a
pre-paid envelope (Letter Pack Light, Japan Post) and mailed. When the
ECG devices were sent from the hospital to patients' homes, a return
envelope was also included. The Letter Pack can be put in any postbox.
ECG, electrocardiogram.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image2/image2}

\end{center}
\end{figure}

\textbf{Figure 2. ECG delivery system between the hospital and patient's
home.} (A) ``One way'': The patient attached the device at the
outpatient clinic. The ECG monitoring was performed during the scheduled
period. After the long-term ECG monitoring, the patients sent the ECG
device to the hospital by post. (B) ``Two way'': The doctors or medical
staff sent the ECG devices to the patients' homes by post on the
scheduled day. The patients put the device on at home. After the
long-term ECG, the patients sent the devices back to the hospital by
post. ECG, electrocardiogram.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image3/image3}

\end{center}
\end{figure}

\begin{CJK}{UTF8}{gbsn}\textbf{Figure 3.　Patients distribution map in the present study.}\end{CJK}\selectlanguage{english} Kobe
University Hospital is located in Kobe, the prefectural capital of
Hyogo, Japan. Most patients live in Kobe City, but some live in the
rural area of Hyogo Prefecture. The median distance to Kobe University
Hospital from patients' homes is 10 km (range: 1.1--183 km).\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image4/image4}

\end{center}
\end{figure}

\textbf{Figure 4. Relationship between the prescheduled monitoring time
and the actual monitoring time}

The doctors and the patients decided the duration of the ECG monitoring
before the examination. The dots on the left indicate the prescheduled
monitoring time. The dots on the right indicate the actual monitoring
time. The ECG monitoring by self-wearing devices could be performed as
planned in most of the patients. ECG, electrocardiogram.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image5/image5}

\end{center}
\end{figure}

\textbf{Figure 5. Representative case.} The patient was a 73-year-old
man who underwent atrial fibrillation catheter ablation 3 months ago. He
sometimes suffered palpitation. We performed the ECG monitoring using
the Duranta delivered by the postal service. The ECG device arrived at
the patient's home on the scheduled day. He put the device on by
himself, and ECG monitoring started. On the next day, the patient felt
palpitations, and paroxysmal atrial fibrillation was recorded by the
Duranta. On the third day, the ECG monitoring ended. The patient sent
the ECG device back to the hospital by post. By using this postal
delivery service, the patient did not need to visit the hospital to
undergo long-term ECG examination. ECG, electrocardiogram.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image6/image6}

\end{center}
\end{figure}

\textbf{Figure 6. Noises or temporary interruption of ECG signals during
the monitoring.} (A) Noises or temporary interruption of ECG signals
were observed during the ECG monitoring:1) electromyographic noise; 2)
electrode motion artifacts; 3) temporary interruption of ECG signals due
to longer distance (over 3--5 m) between the Duranta and the iPhone. (B)
The graph shows the relationship between the actual monitoring time and
ECG noises/interruption percentage. ECG, electrocardiogram. r,
correlation coefficient.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image7/image7}

\end{center}
\end{figure}

\textbf{Figure 7. Results of the patient survey}

ECG, electrocardiogram.

\selectlanguage{english}
\FloatBarrier
\end{document}

