Have you ever been curious about how a personal ECG monitor works?
Atrial Fibrillation (AFib) is the most common form of arrhythmia. It originates from the atria (upper chambers) of the heart. Arrhythmias are irregular heart rhythms caused by disturbances in the electrical signals of the heart. This condition leads to either an increase (tachycardia) or a decrease (bradycardia) in heart rate. Atrial Fibrillation results in a rapid increase in the heart rate and the heart rhythm becomes irregular. It is associated with cardiovascular problems such as heart disease or high blood pressure. Diagnosis of AFib is considered to be challenging as patients either do not display any symptoms or that the symptoms are similar to other cardiovascular diseases. If left untreated, AFib can lead to a stroke.
What is ECG and how is it used?
An electrocardiogram (ECG or EKG) is a test that is routinely performed to diagnose atrial fibrillation and is performed by a qualified medical professional at a hospital or clinic. The test is considered painless and non-invasive and measures the heart rate and heart rhythm. The result of the ECG is a graphical representation (waveform) of the heart’s electrical activity.
While a range of ECG devices are available, the 12-lead ECG is the standard device used at clinical settings. The setup of the 12-lead ECG device involves placing electrodes at ten locations on the body, connected by wires. This device records information on the electrical activity of the heart, collected by the electrodes from twelve different views. The 12-lead ECG is only used for short-term monitoring with the patient in a resting position.
To monitor patients outside the hospital, doctors prescribe personal ECG devices. The most commonly prescribed personal device is the Holter monitor, which is smaller than the 12-lead ECG device. There is evidence that indicates the use of the Holter monitor can be challenging. This is because patients are required to carry the device on their body with all the wiring for a limited duration. The challenge has led to the need for the development of personal devices that are easy to use and capable of long-term monitoring.
How does a personal ECG monitor work?
There are several types of personal ECG monitors that do not require wires due to the recent advances in wireless sensor technologies. These portable devices such as Kardia Mobile, manufactured by AliveCor, are small, easy to carry and can be used for long-term monitoring of the heart. Many of these devices are FDA approved and can capture a medical grade ECG.
The Kardia Mobile ECG monitor is built with two electrodes on which the patient place two fingers (one of each hand). The electrodes are connected by a wireless network to a smartphone or tablet on which the results of the ECG are displayed. The device operates with one lead and records using a single point of contact. It also comes with an application that is downloaded on the mobile device.
Using a personal ECG monitor
After a patient purchases a personal ECG monitor and downloads the app onto their smartphone, they set up an account on which their personal information is entered. Once the setup of the device is complete, the individual is ready to use the device.
The EKG monitor is able to record the ECG in around thirty seconds and simultaneously display it on the smartphone or tablet. The ECG is analyzed by the application, using an algorithm known as Kardia Band, developed by the manufacturer. This algorithm can only classify the EKG as a normal sinus rhythm, bradycardia, tachycardia, atrial fibrillation, unclassified, or unreadable. The results are available immediately and stored for the individual to review. The patient can share the images or strips of the ECGs recorded with their doctor and use the information to track their cardiovascular health.
A 2020 study, published in Neth Heart J, suggests the need for a qualified health professionals to manually analyze the ECGs recorded by the personal ECG monitors. The researchers recommend refining the algorithm to detect and classify the heart rhythm without the need for a manual review.
According to several studies, the diagnostic accuracy and reliability of the personal ECG monitors to detect AFib was found to be close to that of the standard 12-lead ECG device. However, researchers suggest conducting further research to confirm the ability of these devices to diagnose AFib or other heart disorders in larger clinical studies.
It is recommended for patients to seek medical advice from their doctor before deciding to purchase a personal ECG monitor. While the personal ECG monitors are useful in detecting atrial fibrillation, they are not a substitute for medical diagnosis or treatment. Therefore, it is recommended that personal ECG monitors are to be used as a tool for tracking the individual’s heart health, in addition to following the directions of a healthcare professional.
Hickey KT, Riga TC, Mitha SA, Reading MJ. Detection and management of atrial fibrillation using remote monitoring. Nurse Pract. 2018;43(3):24-30. doi:10.1097/01.NPR.0000530214.17031.45
Electrocardiogram. Retrieved from https://www.nhlbi.nih.gov/health-topics/electrocardiogram
Rashkovska A, Depolli M, Tomašić I, Avbelj V, Trobec R. Medical-Grade ECG Sensor for Long-Term Monitoring. Sensors (Basel). 2020;20(6):1695. Published 2020 Mar 18. doi:10.3390/s20061695
Ding EY, Marcus GM, and McManus DD. (2013). Emerging Technologies for Identifying Atrial Fibrillation. Circulation Research. doi: 10.1161/CIRCRESAHA.119.316342
Selder JL, Breukel L, Blok S, van Rossum AC, Tulevski II, Allaart CP. A mobile one-lead ECG device incorporated in a symptom-driven remote arrhythmia monitoring program. The first 5,982 Hartwacht ECGs [published correction appears in Neth Heart J. 2019 Mar;27(3):165]. Neth Heart J. 2019;27(1):38-45. doi:10.1007/s12471-018-1203-4
Bansal A, Joshi R. Portable out-of-hospital electrocardiography: A review of current technologies. J Arrhythm. 2018;34(2):129-138. Published 2018 Feb 23. doi:10.1002/joa3.12035
How to set up your Kardia Mobile: Retrieved from https://alivecor.zendesk.com/hc/en-us/articles/360001941227-How-to-set-up-your-KardiaMobile
FDA Grants First-Ever Clearances to Detect Bradycardia and Tachycardia on a Personal ECG Device. (2019, April 23). Retrieved from https://www.alivecor.com/press/press_release/fda-grants-first-ever-clearances-to-detect-bradycardia-and-tachycardia-on-a-personal-ecg-device/
Koltowski L, Balsam P, Glłowczynska R, et al. Kardia Mobile applicability in clinical practice: A comparison of Kardia Mobile and standard 12-lead electrocardiogram records in 100 consecutive patients of a tertiary cardiovascular care center [published online ahead of print, 2019 Jan 15]. Cardiol J. 2019;10.5603/CJ.a2019.0001. doi:10.5603/CJ.a2019.0001
Image by Gerd Altmann from Pixabay