mhealth’s SnapECG is a medical-grade handheld single-lead electrocardiograph that connects via Bluetooth to a smartphone. It gives a recording of the heart’s electrical pulses, and stores the data to be given to a doctor later. It has received CE mark in Europe and approval from the Chinese Food and Drug Administration (CFDA). It can be used to screen patients who may be suspected to have appropriately-detectable cardiac pathologies such as atrial fibrillation.
It’s strikingly similar to the AliveCor KardiaMobile EKG monitor in form: two metal squares connected by a plastic bridge. It also comes with an adhesive clip sticker for those who want to clamp it to their phone and bring around everywhere.
Setup and recording was extremely easy. I downloaded the app, touched the two squares to turn the SnapECG on, and it was ready to go. At this point, things got a bit trickier but still worked out: I needed two hands on the device, but also needed to press the Record button. So I brought my index fingers to each square, then maneuvered my pinky to the start button on my phone. My electrical signals were given 5 seconds to stabilize as I reset my hands back to resting, and then the SnapECG recorded with live output for 30 seconds. It was an exciting few seconds, as I watched my P wave, PR segment, QRS complex, ST segment, T wave, and (the shadow of) U waves blip by. At the end of this, the app presented me with a report.
The final report is simple. It shows the recording, the heart rate trend, the heart rate distribution, and the rhythm trend. From these data, the SnapECG looks for 5 aberrant signals that may indicate cardiac pathologies, including arrhythmia, tachy/bradycardia, ST elevation/depression, ventricular premature beat, and missed beats. The SnapECG is not diagnostic of aberrancies it captures, and footnotes every reading with “For additional information, share this with your doctor.” Although it’s only 1 lead of an ECG, which ideally uses 12, it’s possible for it to pick up these specific abnormalities. For example, R-R intervals would fluctuate in arrhythmic patients, which can be seen as an irregular pattern. When a patient I used the SnapECG with reported their heart skipping a beat, the device’s ECG tracing showed the missed beats and arrhythmia, but made no recommendations about it.
I reached out to the mHealth, and was told that the device indeed makes no recommendations. Instead, the data should be sent to a doctor, who can make professional judgments about the ECG tracings. Pressing the “Share with Doctors” button simply sends the ECG tracing as a photo to anybody using text, email, AirDrop, etc. Interestingly, it sometimes did highlight when the heart rate was outside of normal boundaries. This selective warning system is confusing and can be misleading.
The SnapECG is cheaper than the AliveCor KardiaMobile ($89.99 vs $99.99). It’s nearly the same thing, but the KardiaMobile has been clinically validated in the US for FDA clearance and is the gold standard for the handheld single-lead ECGs. Furthermore, the SnapECG’s reporting system is confusing; it’s mostly just usable as an ECG tracing viewer. For these reasons, we would recommend the KardiaMobile over the SnapECG in most cases.
Updates 20/10/2018: The original article suggested that the “掌上心电” app may be a useful Chinese alternative to the native app. SnapECG has informed us that this app is for the Chinese market only and should not be used in other countries.
Link: SnapECG homepage…