Eko’s AI platform relies on users capturing good signals in order to successfully perform an analysis. If signal quality is poor or inadequate, Eko’s AI will return a ‘Poor Signal’ result. Detailed below are examples of good and bad quality data. 

Good signal quality

In the examples above the phonocardiogram (PCG) is clear in all examples with minimum artifact or other noise. The ECG is also of good quality even though the deflection of the waveforms differs across all examples.

Users may notice a difference in the amplitude of the waveforms in the PCG when positioning the DUO or CORE in different anatomical locations. As long as artifact is limited and the heart sounds are clear the signal quality should be sufficient to run a successful analysis on the recordings

The amplitude and directionality of the ECG waveforms may also vary across anatomical locations and depend on the position the DUO is placed on the patient’s skin. As long as users can determine QRS complexes and the signal has minimal baseline artifacts, Eko’s AI should be able to successfully analyze the recording. 

ECG Signal Quality meter (available on iOS)

The Eko iOS mobile application provides guidance on the quality of the ECG signal captured when connected with the Eko DUO product. The meter is located at the bottom left of the screen as seen below.

Users can better determine the quality of the ECG signal by monitoring both the ECG waveform and the signal quality meter as they are assessing their patient. As the ECG signal improves the signal quality meter will also move into the green or optimal zone.

Users can seek guidance on improving ECG signal quality while using the Eko application by tapping on “Poor ECG quality detected. Learn more.” This will lead users to a guide with three recommended positions.

Bad signal quality - Phonocardiogram (PCG)

Poor signal quality may manifest differently in the PCG than the ECG, and vice versa. Below are examples of poor heart sound or PCG recordings.

Bad signal quality - Electrocardiogram (ECG)

Below are examples of poor ECG signal quality:

Improving signal quality

If the quality of the data collected is poor or insufficient Eko’s AI software cannot run a proper analysis. Poor data quality can increase the risk of false positive findings or may not yield useful information for the clinicians. Tips to gather the best data detailed below. 

Minimum data required for Eko to analyze

Eko’s AI platform requires a minimum of 15 seconds and no more than 30s of data to conduct an analysis. If insufficient data is captured users will see the error message below:

Recording length defaults to 15 seconds; users can increase the length of time up to 30 seconds. Recordings longer than 30 seconds will not return AI results.

Ensuring adequate Bluetooth connection

Eko’s stethoscopes require Bluetooth Low Energy (BLE) 4.0 or above (Eko recommends BLE 4.2 or above for use with the second generation CORE) in order to connect with the Eko software. If the Bluetooth connection is disrupted users will see an error message indicating “Weak Bluetooth Connection” appear at the top of their screen, see below:

If the Bluetooth connection is poor the transmission of data is likely being disrupted and can result in the AI analysis being incomplete or inaccurate. If users are receiving the message above, follow the steps below to improve the Bluetooth connection:

• Ensure that the Eko stethoscope is the only Bluetooth device connected with the mobile device being used.
• This includes disconnecting smart watches, headphones, hearing aids, and other Bluetooth peripherals.
• Limit the distance between the Eko stethoscope and the Eko application / mobile device being streamed to.
• Limit any physical obstruction including human body parts between the Eko application / mobile device being streamed to.
• Try to limit use of other Bluetooth devices in the vicinity of the Eko stethoscope. 

Improving PCG signal quality

Due to the different methods in which the Eko CORE and DUO capture sound, improving the PCG quality may differ between devices. 

Improving PCG quality with the Eko CORE

Active Noise Cancellation

The Eko CORE includes Active Noise Cancellation (ANC) technology to reduce the occurrence of environmental noise during auscultation. This is especially noticeable when viewing the waveforms and listening to the auscultation using the Eko software. Eko recommends that ANC be kept ON when conducting an analysis (ANC is ON by default). Review below:

Notice that there is more artifact in the sample recorded with ANC OFF (especially apparent in the baseline of the phonocardiogram or PCG) than with the ANC ON. Gathering sounds with minimal amount of ambient noise or other kinds of artifact maintains optimal signal quality and will yield the best results from the Eko AI analysis.  

Environmental noise includes sounds emanating from outside the patient’s body. If a patient has been placed on a ventilator, LVAD, or other device where sound is being generated from inside the patient’s body these sounds will not be diminished.

ANC is not available with the first generation Eko CORE or the Eko DUO.

Selecting a different diaphragm

Depending on the size of the patient, users may find that heart sounds are better captured with certain diaphragms than others. For example, the pediatric diaphragm may be best used with smaller patients. For any diaphragm, ensure that the surface is flush with the patient’s skin and that firm pressure is being applied. 

Minimizing movement artifact

While the ANC technology will minimize much of the environmental noise captured by the CORE, the PCG may still be prone to movement artifacts. To minimize the movement artifact:

• Hold the stethoscope still and firmly in place before initiating an analysis.
• If clothing is moving across the stethoscope, either place directly on the patient’s skin or have the patient remove the clothing that is in contact with the stethoscope before recording

Improving PCG quality with the Eko DUO

Minimizing movement artifact

The DUO is sensitive to vibration and hand noise. Gripping and pressing the DUO firmly against the skin and keeping the patient and the DUO as still as possible can limit movement artifact. If clothing is moving across the DUO and creating movement artifacts, have the patient remove the clothing that is in contact with the stethoscope before recording. 

Minimizing environmental noise

While the DUO is designed to gather sound when the diaphragm is placed directly on the patient’s skin it may still gather environmental noise especially if used in a loud environment. If background noise is creating too much artifact in the PCG, users may need to seek a quieter area to conduct their analysis. 

Improving ECG signal quality

Improving ECG signal is only applicable to the Eko DUO stethoscope as the Eko CORE cannot capture a patient’s ECG. 

Contact with patient’s skin 

If both metal leads are not clearly in contact with the patient’s skin, then the device cannot capture an ECG. This may happen if the device is not flush against the patient’s skin. Sometimes a person’s chest is more contoured, which can make it difficult to lay the device flat on the patient. Best placement may vary, the DUO can be held in a variety of positions (vertically, horizontally, angled) across the patient’s anterior thoracic region in order to capture the best ECG signal. 

The DUO is sensitive to vibration and hand noise. Gripping and pressing the DUO tightly against the skin into position and keeping your hand as still as possible is essential to collecting clean signals.

Apply firm pressure against the chest to ensure good ECG electrodes contact. Use constant pressure to make sure the connection between the skin and the electrodes stays tight. 

Preparing a patient’s skin

If the patient has thick chest hair, dry skin, or body fat and it is difficult to get a clean ECG signal, users may want to:

• Shave the patient’s chest if hair is potentially obstructing the ECG signal
• Apply water, saline, or ECG gel to the patient’s skin in order to improve conductivity and ECG signal. Eko recommends applying these solutions to the patient’s skin not directly on the DUO.
• Patients with dry skin may be most in need of having additional solutions applied to their skin.
• Lotion is not an appropriate alternative to water, saline, or ECG gel. Properties in lotion may impede the signal.
• Contact solution can also be used as an alternative to water, saline, or ECG gel.

Avoiding power sources

Proximity to nearby power sources (e.g. wall outlets). ECG leads (even typical 12 lead ECGs) are affected by electromagnetic fields generated by 50-60Hz power sources. Record data away from wall outlets and other power sources.

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