This research received no external funding. We thank Lisa Tiedemann, Ester Krist and Tobias Anke for technical support.

This study was performed according to the Declarations of Helsinki and approved by the Ethics Committee of the Aerztekammer Westfalen-Lippe (reference number 2019-456).
1. Study
<ol>
	<li>Instruct subjects on how to use the smartwatch for proper ECG recording.</li>
</ol>
2. Recording of a standard 12-lead ECG by a common device
<ol>
	<li>Use a common ECG device for standard ECG recording.</li>
	<li>Adjust the paper running speed to 50 mm/s.</li>
	<li>Perform the ECG...

<ol>
	<li>Turakhia, M. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rationale+and+design+of+a+large-scale,+app-based+study+to+identify+cardiac+arrhythmias+using+a+smartwatch:+The+Apple+Heart+Study.">Rationale and design of a large-scale, app-based study to identify cardiac arrhythmias using a smartwatch: The Apple Heart Study.</a> American Heart Journal. 207, 66-75 (2019).</li><li>Dorr, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+WATCH+AF+Trial:+SmartWATCHes+for+Detection+of+Atrial+Fibrillation.">The WATCH AF Trial: SmartWATCHes for Detection of Atrial Fibrillation.</a> JACC Clinical Electrophysiology. 5 (2), 199-208 (2019).</li><li>Hochstadt, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous+heart+rate+monitoring+for+automatic+detection+of+atrial+fibrillation+with+novel+bio-sensing+technology.">Continuous heart rate monitoring for automatic detection of atrial fibrillation with novel bio-sensing technology.</a> Journal of Electrocardiology. 52, 23-27 (2019).</li><li>Baquero, G. A., Banchs, J. E., Ahmed, S., Naccarelli, G. V., Luck, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+12+lead+electrocardiogram+recordings+using+smart+phone+technology.">Surface 12 lead electrocardiogram recordings using smart phone technology.</a> Journal of Electrocardiology. 48 (1), 1-7 (2015).</li><li>Desteghe, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Performance+of+handheld+electrocardiogram+devices+to+detect+atrial+fibrillation+in+a+cardiology+and+geriatric+ward+setting.">Performance of handheld electrocardiogram devices to detect atrial fibrillation in a cardiology and geriatric ward setting.</a> Europace. 19 (1), 29-39 (2017).</li><li>Samol, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prevalence+of+unknown+atrial+fibrillation+in+patients+with+risk+factors.">Prevalence of unknown atrial fibrillation in patients with risk factors.</a> Europace. 15 (5), 657-662 (2013).</li><li>Nigolian, A., Dayal, N., Nigolian, H., Stettler, C., Burri, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diagnostic+accuracy+of+multi-lead+ECGs+obtained+using+a+pocket-sized+bipolar+handheld+event+recorder.">Diagnostic accuracy of multi-lead ECGs obtained using a pocket-sized bipolar handheld event recorder.</a> Journal of Electrocardiology. 51 (2), 278-281 (2018).</li><li>Foster, K. R., Torous, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Opportunity+and+Obstacles+for+Smartwatches+and+Wearable+Sensors.">The Opportunity and Obstacles for Smartwatches and Wearable Sensors.</a> IEEE Pulse. 10 (1), 22-25 (2019).</li><li>Lau, J. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=iPhone+ECG+application+for+community+screening+to+detect+silent+atrial+fibrillation:+a+novel+technology+to+prevent+stroke.">iPhone ECG application for community screening to detect silent atrial fibrillation: a novel technology to prevent stroke.</a> International Journal of Cardiology. 165 (1), 193-194 (2013).</li><li>Einthoven, W., Fahr, G., De Waart, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+direction+and+manifest+size+of+the+variations+of+potential+in+the+human+heart+and+on+the+influence+of+the+position+of+the+heart+on+the+form+of+the+electrocardiogram.">On the direction and manifest size of the variations of potential in the human heart and on the influence of the position of the heart on the form of the electrocardiogram.</a> American Heart Journal. 40 (2), 163-211 (1950).</li><li>Burch, G. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=History+of+precordial+leads+in+electrocardiography.">History of precordial leads in electrocardiography.</a> European Journal of Cardiology. 8 (2), 207-236 (1978).</li><li>Leslie, W. S., Urie, A., Hooper, J., Morrison, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Delay+in+calling+for+help+during+myocardial+infarction:+reasons+for+the+delay+and+subsequent+pattern+of+accessing+care.">Delay in calling for help during myocardial infarction: reasons for the delay and subsequent pattern of accessing care.</a> Heart. 84 (2), 137-141 (2000).</li><li>Tison, G. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Passive+Detection+of+Atrial+Fibrillation+Using+a+Commercially+Available+Smartwatch.">Passive Detection of Atrial Fibrillation Using a Commercially Available Smartwatch.</a> JAMA Cardiology. 3 (5), 409-416 (2018).</li><li>Samol, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recording+of+Bipolar+Multichannel+ECGs+by+a+Smartwatch:+Modern+ECG+Diagnostic+100+Years+after+Einthoven.">Recording of Bipolar Multichannel ECGs by a Smartwatch: Modern ECG Diagnostic 100 Years after Einthoven.</a> Sensors (Basel). 19 (13), (2019).</li><li>Avila, C. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+Use+of+Apple+Watch+4+to+Obtain+3-Lead+Electrocardiogram+and+Detect+Cardiac+Ischemia.">Novel Use of Apple Watch 4 to Obtain 3-Lead Electrocardiogram and Detect Cardiac Ischemia.</a> Permanente Journal. 23, (2019).</li></ol>

Smart devices like smartphones and smartwatches are increasingly used in daily life and medical care1. These new devices and apps may have a significant impact on health awareness of the population, but their effective use needs to be tested in studies8. To the best of our knowledge, our group was the first to develop this method of single-lead ECG recordings corresponding to the conventional Einthoven ECG leads I-III using a smartwatch14.
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Smartwatches or other so-called "wearable devices" show increasing popularity and a steeply rising daily use in Western countries. Nearly 80% of US-Americans own a smartphone and more than 10% have a smartwatch1. Due to a photoplethysmographic sensor using LED-light and photodiodes, some smartwatches can record pulse frequency and irregularities1. This feature enables the detection of arrhythmias, especially AF, with high diagnostic accuracy2,3. For authentic ECG arrhythmia detection, portable, handheld, and wearable ECG devices have been developed to enable smartphone-assisted ECG recordings. Nevertheless, these devices allow patient-activated recording of electrocardiograms only if the patients&rsquo; compliance for carrying the ECG device is extremely high4,5,6,7.
Thus, the optimal tool for a patient&rsquo;s medical surveillance would be a smart device for daily use. Some last generation smartwatches enable a single-lead ECG recording comparable to bipolar lead Einthoven I from a standard 12-channel ECG using the backside of the watch as the positive and the crown as the negative electrode8. ECG recording is patient-controlled and activated if symptoms occur. Thereafter, an application creates a PDF document for further analysis by a healthcare professional. Nevertheless, using only a single-lead ECG for discrimination of P waves for diagnosis of sinus rhythm is sometimes insufficient9 for detection of the P wave and often multiple ECG leads are required5. In addition, multichannel ECG recording is mandatory for diagnosis of most acute or chronic structural heart diseases like myocardial infarction (MI), pulmonary embolism, or signs of acute heart failure.
More than 100 years ago, Einthoven developed a method for recording of a bipolar three- channel ECG10. This three-channel ECG offers the opportunity to identify the electrical heart axis and possibly the myocardial ischemia as well, especially in inferior regions of the myocardium11. Therefore, in clinical daily practice bipolar Einthoven leads I-III are essential parts of the 12-lead ECG and enable heart rhythm determination or detection of myocardial ischemia.
Early diagnosis and especially early treatment of myocardial infarction has improved substantially during recent decades. Nevertheless, especially early after the onset of symptoms, many patients hesitate to contact professional help. Thus, first medical contact and initiation of adequate treatment is often delayed12. Registration and transmission of a patient-directed ECG early after the onset of symptoms might accelerate specific treatment and thus enable a better patient outcome7. Until now, ischemia detection by smart devices is limited, because mainly single-lead (Einthoven I), or as in our study, maximal three-lead (Einthoven I-III) ECGs can be recorded, which only represent a limited area of the myocardium.
Several studies used patient-directed devices like portable ECG recorders, smartphones, and very recently smartwatches, for detection of AF in heart patients1,2,5,9. The Apple Heart Study and the WATCH AF trial used the photoplethysmographic LED-light sensor of the smartwatch for detection of an irregular or variable pulse, which correlates with arrhythmia like AF1,2. Insufficient signal quality was the limiting factor in these trials, leading to a high dropout rate2. Another smartwatch trial used photoplethysmography for AF detection, but also showed reduced diagnostic accuracy compared to regular ECGs13.
The detection of AF by the registration of pulse irregularities is the limiting factor of photoplethysmography, because heartbeat variabilities due to extra systoles or sinus arrhythmia may also cause pulse irregularities. Thus, recording of an ECG by a smartphone or smartwatch may increase the sensitivity and specificity of arrhythmia detection. Several smartphone compatible devices can record a bipolar single-lead ECG simulating Einthoven lead I5,9. In one study, a bipolar smartphone ECG device was used for AF screening9. In this trial, a small voltage of P waves in lead I led to incorrect AF determination, a limitation when only a single-lead ECG is available9. ECG devices for AF screening were also tested in hospitalized patients on cardiologic and geriatric wards5. Diagnostic accuracy of the automated algorithms was only suboptimal and additional 12-lead ECGs were often mandatory. Most of these devices have the limitation of only one ECG lead recording (Einthoven I), which is not always sufficient to ensure arrhythmia or repolarization detection.
Only one small case series of five patients demonstrated that a conventional 12 lead ECG is recordable by a conventional bipolar smartphone device after modification for unipolar lead recordings with ECG tabs and wires with alligator clips4. They showed ECG recordings with good signal quality, but the limiting factor is the need for device modifications that complicates patient-directed self-ECG recording.
In contrast, we performed the first study for recording an ECG with a smartwatch with the three bipolar Einthoven leads as a proof of concept in healthy subjects. We were able to show a high grade of consistency between the smartwatch leads and the Einthoven leads from a standard ECG using the following simple protocol.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Apple Watch Series 4</td>
			<td>Apple</td>
			<td>Smartwatch with bipolar ECG function</td>
		</tr>
		<tr>
			<td>IBM SPSS Statistics</td>
			<td>IBM</td>
			<td>version 25 for Mac</td>
		</tr>
		<tr>
			<td>MAC 5500</td>
			<td>GE Healthcare</td>
			<td>Standard 12 channel ECG device</td>
		</tr>
	</tbody>
</table>

patient directed recording of a bipolar three-lead electrocardiogram using a smartwatch with ecg function

Cardiac arrhythmias and cardiovascular diseases are a major public health problem in developed countries. A major goal in preventive medicine is the reduction of cardiovascular death by early detection of atrial fibrillation (AF), which may cause stroke, or early detection of life-threatening myocardial ischemia in acute coronary syndrome. Detection of arrhythmia is often challenging if symptoms occur when patients have no chance for immediate electrocardiogram (ECG) diagnostic testing, or if the observation time period is short or an immediate visit to their doctor is not possible. Smartwatches and other wearable devices are able to record a single lead ECG recording, but a single lead ECG is often not sufficient for diagnosis of cardiovascular disorders. Even diagnosis of AF can be difficult with only information from a single lead bipolar ECG. Some smart devices use photoplethysmography for detection of cardiac rhythm, but this technique can only give indirect hints of the underlying cardiac rhythm, is prone to interferences, and cannot be used for detection of myocardial ischemia. A three-lead bipolar ECG like the Einthoven leads used in regular ECGs can add useful information concerning arrhythmia detection or even diagnosis of other cardiovascular diseases like ischemia. Therefore, we describe a protocol for the patient-directed recording of an Einthoven three-lead ECG using a smartwatch.

In a cohort of 100 healthy subjects (66 female) we investigated the feasibility of our smartwatch recording protocol. The subjects' characteristics are shown in Table 1. After a short tutorial all volunteers managed the ECG recording procedure with the smartwatch. All 300 smartwatch ECGs were useable for further analysis with at least adequate signal quality for diagnostics purposes. Of the total ECGs, 277 (92%) were of good quality and 23 (8%) of moderate signal quality. Three blinded cardiologists were...

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Patient Directed Recording of a Bipolar Three-Lead Electrocardiogram using a Smartwatch with ECG Function

We describe a protocol for the patient-directed registration of a three lead bipolar electrocardiogram by a smartwatch that functions identically to the Einthoven leads from standard electrocardiograms. This enables patients to record electrocardiograms on their own immediately after the onset of symptoms.

Cardiac arrhythmias and cardiovascular diseases are a major public health problem in developed countries. A major goal in preventive medicine is the ...

This protocol enables subjects owning a smartwatch with ECG function to record three bipolar signal lead ECGs comparable to Einthoven leads one to three from a standard ECG. This technique may help to detect cardiac arrhythmias or myocardial ischemia. Subjects could help a doctor identify ECG abnormalities immediately after onset of symptoms.This method can principally be applied to all bipolar ECG recording devices and smartwatches with ECG function, except for the protocol for sending PDF to the doctor, which is specific to the device app. It is important that the subject is able to generate a good skin contact, especially during recording of leads two and three. It may be difficult to record Einthoven leads two and three because the watch has to be placed in the lower abdominal of the individual.Therefore a resting position is mandatory. Demonstrating the procedure will be Sven Kaese, a colleague from our department. To record a standard ECG, use a common ECG device and adjust the paper running speed to 50 millimeters per second.Perform the recording after a five minute resting period in a supine position. Place the right and left arm electrodes near the shoulders and the right and left leg electrodes near the ankles. Then place the V1 and V2 electrodes in the fourth intercostal space at the right and left parasternal lines respectively.Place the V4 electrode in the fifth intercostal space at the midclavicular line and the V3 electrode between the V2 and V4.Then place the V5 electrode in the fifth intercostal space at the anterior axillary line and the V6 electrode at the mid axillary line. Once all electrodes are in place, record a standard 12 lead ECG with the ECG device. Record the smartwatch ECG immediately after recording the standard ECG.Enable the application for ECG recording, which will record a 30 second ECG after proper skin contact with the smartwatch. Record Einthoven one by placing the back of the smartwatch on left wrist and the right index finger on the crown. Then, record Einthoven two by placing it on the left lower abdomen and the right index finger on the crown.Finally, record Einthoven three in the same position, but with the left index finger on the crown. Ensure that the right and left index finger do not contact the skin of the wrist of lower abdomen and that the subject does not move during the recording. Use the Send PDF to Your Doctor function to create a PDF document of every smartwatch ECG lead.Then print the digital ECG on paper for comparison with the standard ECG. Classify all smartwatch ECGs as moderate quality if at least three consecutive QRS complexes show noise free signal quality and there are no artifacts in the isoelectric lines between complexes. If this is true for 10 QRS complexes, classify the ECG as good quality.Then, perform statistical analysis on the ECGs. The smartwatch recording protocol was tested on 100 healthy subjects, all of whom managed the ECG recording procedure after a short tutorial. Of the total recorded ECGs, 92%were of good signal quality and 8%of moderate signal quality.Despite different writing speeds of the standard and smartwatch ECG curves, the morphologies of the three channels were clearly identical. Three blinded cardiologists were asked to assign the smartwatch ECGs to the corresponding Einthoven leads in each subject and all three correctly assigned the ECGs from 89 participants. All assignment errors were made in the ECGs with good signal quality, but the errors occurred in statistically older subjects.When attempting this procedure, the most important thing is to perform recordings under resting conditions to obtain best ECG signal quality. Chest lead ECG recordings may also be recorded with mobile device to give additional informations of the interior wall of the left ventricle. This technique may enable widespread of diagnostic potential in an outpatient setting for cardiac disorders.

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8.5K vistas.  Ruhr University Bochum. Este protocolo permite a los sujetos que poseen un reloj inteligente con función ECG registrar tres ECG de plomo de señal bipolar comparables a los cables Einthoven de uno a tres de un ECG estándar. Esta técnica puede ayudar a detectar arritmias cardíacas o isquemia miocárdica. Los sujetos podrían ayudar a un médico a identificar anomalías del ECG inmediatamente después de la aparición de los síntomas.Este método se puede aplicar principalmente a todos los dispositivos de ...