A personal ECG monitor is a small device that records the heart's rhythm when a person touches it with their fingers, and sends the recording to a phone app. It is also called a personal ECG device or a single-lead ECG. Doctors review the recordings on a website. In India, it is sold online and at chemists, mainly to people who feel their heart racing or skipping now and then.
An ECG, or electrocardiogram, is the tracing of the heart's electrical signals. In a hospital, an ECG uses ten stickers on the chest, arms and legs. A personal ECG monitor has two metal pads instead. When a person rests fingers of each hand on the pads, the device picks up the heart's signals between one arm and the other. This gives one view of the heart, called a single lead. Some models have a third pad, which touches the left leg and gives six views. One view is enough to judge the heart's rhythm. It is not enough to rule out a heart attack.
The problem it solves is timing. Many rhythm problems come and go. A heart may race for ten minutes once a week and be normal by the time the person reaches a clinic. Imagine a 61-year-old retired railway employee in Indore who sometimes feels his heart fluttering in the evening. His doctor asks him to keep the device with him. One evening, the fluttering starts while he is watching television. He rests his fingers on the device for 30 seconds, and the app shows the tracing. An algorithm in the app labels it "possible atrial fibrillation". Atrial fibrillation is an irregular rhythm that raises the risk of stroke. The recording goes to his doctor's online dashboard. The next day, his doctor reads it, confirms the finding and starts treatment.
A person can also send a recording to a remote ECG interpretation service, which returns a specialist's reading. Some clinics add the recordings to the patient's file in their ambulatory EHR.
How is this different from a Holter monitor? A Holter monitor records the heart all the time for one or two days, through stickers on the chest. A personal ECG monitor records only when the person feels something, for 30 seconds at a time, but the person can keep it for years. Both are forms of remote patient monitoring. The algorithm that labels the rhythm is regulated as software as a medical device (SaMD).