Using your cell phone to check for aFib

[SeymourB]

I am still in Watch & Wait (Worry), and do not have a diagnosis of afib.

I have been watching my heart rate and other parameters, such as rMSSD and HRV using my Galaxy S8+ cell phone's rear camera and various Android apps. I don't like the idea of having to carry as separate device to do such testing.

After reading a thread on another Home screening device to detect AFib,

healthunlocked.com/cllsuppo...

I went looking for the latest Android apps in heart monitoring, and came across a monthly subscription based FibriCheck that is specifically designed to test for fibrillation:

help.fibricheck.com/hc/en-us

"The FibriCheck app illuminates your fingertip with the flash of the camera of your smartphone and measures the difference in light absorption over time. When the blood vessels are filled with blood right after a heartbeat the absorption will be high. In between heartbeats the amount of blood in the vessels decreases and absorption will be lower. The result of this measurement is called a photophlethysmogram or PPG.

The big advantage of this technique is that all you would need to check your heart rhythm is a smartphone with a camera and flash. So no need to buy additional hardware or devices."

They offer their white papers and sponsored study results:

fibricheck.com/research/

It is CE and FDA approved. It's a Dutch company.

There are both Android and iPhone apps.

I loaded it to do the free, 24 hour test, and to see its features. You use your email for a username, and create a password.

It requires a monthly €3,99 subscription, or €5,99 for one month. It provides web site to store measurements.

If offers review of results by "medical experts" for an additional €9,99. Or you can sign for a premium account that reviews all results and provides a weekly report, for €10/month.

You can also share a report via email immediately after viewing the report on your phone by tapping the standard android share symbol in the app.

Measurement reports are stored, and can be forwarded to your doctor, or you can download them as PDFs or print them.

It also works with some FitBit devices, but only in UK, Ireland, Netherlands, and Belgium.

When you start a measurement, you put your finger on the camera, and it starts recording for 1 minute. It then asks for Context - symptom buttons for:

No symptoms

Palpitations

Chest Pains

Shortness of Breath

Lightheadedness

Confusion

Fatigue

Other

And asks if you were:

Exercising

Walking

Standing

Sitting

Sleeping

Other

On my 24hr trial, it immediately said the measurement was reviewed by a medical expert, and made a medical grade diagnosis. So I suspect it was done via AI (artificial intelligence).

I can then click a Generate Report button, and then a View Report button. I shared to my own email, and it sent a PDF that said:

FibriCheck expert panel

The measurement in this report has been reviewed by the FibriCheck expert panel

NO ACTION REQUIRED

There were no significant abnormalities identified.

Your analysis result

REGULAR RHYTHM

Your heart rate and heart rhythm are within the boundaries of normal values. There are no significant deviations found.

Information for your physician

Your patient participated in a project where the heart rhythm was monitored using the FibriCheck smartphone or smartwatch

application. FibriCheck is a CE (smartphone & smartwatch) and FDA (smartphone) cleared medical device. The findings made in this report are indicated above and the details of the heart rhythm measurements are enclosed below. If you have questions with

respect to these heart rhythms you can reach out to FibriCheck through [e-mail].

This test result is not a diagnosis. It does not replace medical advice, please seek professional medical assistance if you are or believe you are suffering from any medical problem. This device

does not detect or measure all heart rate, heart rhythm or heart waveform changes, especially those related to ischemic heart conditions. This report is based solely on the PPG recording submitted for analysis. Medical conditions, symptoms and activities are not considered but are recorded to assist your physician in making a diagnosis. Advice is based on a normal adult population. The information provided by FibriCheck as well as the clinical analysis and report provided by FibriCheck are useful aids in user self-evaluations, but are not intended to be a replacement for complete 12-Lead ECG exams or medical evaluations by your personal physician.

---

The above disclaimer is repeated on each page of the report.

It then provides some patient education info on heart anatomy and measurement.

Then there's a page that reports the details:

FibriCheck Report

Name

se br (minimum 2 characters for first and last name)

Date of birth

1955-02-01 ) (not my real birth date)

FibriCheck measurement performed on: 2019-12-14 18:04

Measurement received on:

2019-12-14 18:05

Measurement reviewed on:

2019-12-14 18:05

Device:

samsung SM-G955U

Heart rhythm results

Your heart rhythm is regular. You reported FATIGUE.

Heart rate results

Your heart rate is slightly slower than normal (signs of bradycardia), it averages at 59 beats per minute. You indicated you were

sitting before the measurement.

Suggestion

A slightly slowed heart rate after sitting may not be harmful. However, you did report to experience symptoms. Repeat the

measurement at regular time intervals and when you are experiencing these symptoms again. If you keep experiencing these symptoms, it may be advised to discuss this with your physician.

---

Then it reproduces:

A graph of the measurement of the 60 second PPG signal

A tachogram of each detected heartbeat showing how many heartbeats in each interval

A Lorenz plot showing the variation from beat to beat in milliseconds - mine was centered blob plot (good).

You can see examples at:

fibricheck.com/the-fibriche...

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My thoughts:

The app is well done, and generally clear and easy to use. The web site had some confusing pricing info, which I reported. The site does say:

"The free trial will end automatically after 24h. After the free trial FibriCheck does not automatically charge or prolong a subscription. If you would be interested in a continued use of FibriCheck, you have to manually activate another subscription."

That's good. I'm not sure how it acts if you sign up for just one month.

I like the fact that it asks for Context and if I was Exercising

, Walking, Standing, Sitting, or Sleeping, but I think they should add Reclining, and possibly Excited. You can enter those under Other, but I think it's important for them to gather more categories of data for later studies.

This sort of app (I have others) is used in studies that will be published in journals, so you are consenting to use of your data, though not your identity. The monthly subscription keeps the riff-raff out - otherwise, misanthropes might purposely upload bad data to get their LOLs for the day.

As they note, it's not a substite for a true EKG. I hasten to add that the Holter monitor I wore for a few days last year was incredibly overpriced (they charged my insurance over $500, and new Holters can be purchased for around $1000) for what it did, and I don't imagine the medical techs do any maintenance on them but check the battery on it. Disclaimer: I am an electronics tech, but I don't have a medical electronics certificate. I estimate the cost for parts and manufacturing for a Holter would be under $100. I look forward to really inexpensive Holter monitors someday when some company makes them available for the 3rd world and proves their safety and utility.

I showed some of my other heart apps to my cardiologist last year, and he was able to point out features of the wave form for me, and told me about the sort of things it cannot show. A true EKG measures the difference in electrical nerve signals in multiple areas, where this measures only the intensity of the pulse in your finger. Nevertheless, if it does detect afib, because that's so easy to detect based on pulse peaks and timing. You need to follow up with your doctor, who will probably welcome the additional Context data.

I think the whole Medical Expert review thing implies humans are looking at it, but I think it's done by AI - which is ok by me for arrhythmias, given that it's essentially numerical. But a human might see more.

One of FibroCheck's validation papers:

fibricheck.com/fibricheck-b...

fibricheck.com/clinical-tri...

Finally, I wish that the FibriCheck people would try to certify particular cell phone models. My phone is an older, fairly high end model. But the basic technique of using your finger to cover both the flash and lens will work on most phones, I think. The only difference might be in the signal strength. But they do offer the free 24 hour trial.

Tips:

You do need to hold yourself and your phone steady. If you are measuring while standing, rest you cellphone up against some immovable object - then it's only a matter if you wiggle your finger. The warning about removing the case is to make sure you don't have clear plastic covering the lens, I think, and that your finger can access ok. I left my case on. If you have a callous on your finger, use a different finger or different part of the finger.