ECG leads & special ECG leads – confusing terms from the field of electrocardiography?

Last Updated on August 20, 2023 by pg@petergamma.org

ECG devics where developed a long time ago. Somewhere we found the definition that an ECG lead is a measurement with an ECG device which is then followed by another measurement with an ECG device, after the switch on the ECG device is switched to the next ECG lead by the scientist. Old ECG devices had switches to switch to the next lead for the next measurement. But contemporary ECG devices are multi-channel devices, and often the term ECG lead can be replaced by the term ECG channel.

But often if we are looking for something, which has to do with ECG leads, we cannot find it, and we retreat confused from our search. How long did it take for us personally to understand what a 3 lead ECG device is, and that it is one of the most interesting heart rate monitor devices which is available for us personally? A device which beats Rob ter Horsts two Polar H10 chest strap reference devices with one measurement as far as accuracy is concerned. And it is not our reference device for accuracy studies, it is our daily driver. A device Rob ter Horst can only dream of? Is Rob not allowed to use these devices, since the companies who offer him the watches for his tests do not allow to use such highly accurate devices for his tests? He might eventually find out, that his smartwatches are inaccurate and deliver data which cannot be reproduced?

Rob ter Horst uses two Polar H10 chest straps to get accurate heart rate measurements. But ECG device developers are ahead from Rob. They use three lead ECG devices instead of two Polar H10 chest staps. What does that mean? A 3 lead ECG device as for instance the TA 220 from iWorx records ECG signals from 3 ECG channels simultaneously. This gives the iWorx TA 220 the higher accracy than the accuracy of Rob ter Horts two Polar H10 chest straps. Rob makes two measurements, the 3 lead ECG device makes 3 ECG measurements simultaneously, which offers a higher accuracy. This is now clear for us personally.

But if we are looking for a Mason-Likar electrode placement with 3 leads, which is required for gold standard heart rate recordings, we cannot find it anywhere. We can only find Mason-Likar electrode placement with 12 leads, but not with 3 leads.

The iWorx TA 220 records ECG on 3 channels with 5 electrodes and 5 wires, one is ground. But does the iWorx TA 220 use the Mason-Likar electrode placement with 3 leads? We where not able to find the answer to this question. The TA 220 makes three simultaneous ECG recordings with 3 channels, which are connected over 5 wires to 5 electrodes. But how are these electrodes sticked to the body correctly?

We can find information about ECG monitoring leads and special leads in the Indian Pacing and Electrophysiology Journal:

https://pdf.sciencedirectassets.com/313515/1-s2.0-S0972629216X0006X/1-s2.0-S0972629216313092/main.pdf?X-Amz-Security-Token=IQoJb3JpZ2luX2VjEAkaCXVzLWVhc3QtMSJGMEQCIH6ycpuwQnoT2tlAFjyCHx2wSDKJiDqUgUoFuc3g7T%2BFAiABYRcBWolpfXoRw5QuTQhESc%2BCYtdK%2BiyUFuyPRAx2ziq7BQjC%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F8BEAUaDDA1OTAwMzU0Njg2NSIM5Jg8XEn4BKm4YDRpKo8FnBwfpA0tz0x3LWlPzi8AeQ%2BDyHYVWNyjPfdW%2Bd2LRhJlyT5q%2B6GiecY%2F6Hc9yMlxKmwBYYwJWKGaIcZ8OXJpR9quJcPDV2pAQ%2B94%2FX8pe4pBehM3eY62o%2FFZSoA8YsD59FDLWavzO1FesGlKmLgr15abPX73tYdCShoMuEyqTzjSpatIJsVTlpJZS8EUDpD9nxpP9KHA27NGFvIWnaWmQxxpGEf%2BQjH4jPs0L6FB8KMdanjRCO9gBoNm1gvBsjUGTclhGguXGqZ%2F%2FCCFFRDPf5J9j7YgHHw%2B7g%2BQdLDxYbyNFq1wQL0ZpslI2nDL8%2FghYhdCqz2h7zT7eFE1gZy4waUihCFQgJx4MVXwcK1FgxUJp41%2FdtQaJBOfkiZX%2BTmZ3dfb07enZNv0SKdi82Qfsm9aD2cqm6i0v9q6aIzajB9H3hfEyGJcg0JQujL%2FCwNj8UaRQcfgTvEb4Wh626oqsd1AIqBgGnvMB3JRlV3Rhdp%2BvynEKBZF9JGqV0KfmRcVw5ijiXzT4wH6Fz1caRDjGn2Rywn3tRglncMUSC456wp6jsz4QmqOrPGYZTXOs8QyqqCm4k1%2BaIOp6FAdjjKlxGGo1NyUZ1tEiJlZ2FSa7Scg%2Fa4dPLGoa3Dbc2JLE1qba0YYiRRcbDlXhcP8G%2B5zWjwNtKVWMmDgYlEb8%2FB27eVw6cMsNDmrOuOHwBm8TbrFXmMcXaLdruIDqGOuvANQ51Wj0PJWm6nLxECWrNQG9eoG4pNW%2FLIw3DtVDRhRq%2FikRLjx13oavEeQSfQnElhPS86snRIdVqDnQo7P99CNaUeriVdem4kUwVd1QW65%2B09ovypp8AhQUgJDFihLZpeeKTpLcW7MZsUqA06I3vxYfjDxgYmnBjqyAanymmHEcge4LxHSzStSs7DCuVtu8V0U3Qo3XPpjoGDTDJLvhugpSWuNNXr1iq%2Bh1i%2BzgRYaekDBrcjT14bdOwZE5Ow7TunPu5PtXm%2FRccbq9A%2Frcw%2Fl%2Fnh2%2BE7j0HBJPosuDdVR3soxgVr02A4WgpfGYuLtMBb6pY%2FCa2LoXQ%2BnF6kxDa6l6Shag4rnWNx9IY8BGrSja%2Fqff36P4eOhL%2FNZ51ON9JDCr4lTPCd8oTHkthU%3D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20230820T165418Z&X-Amz-SignedHeaders=host&X-Amz-Expires=300&X-Amz-Credential=ASIAQ3PHCVTYUK4BAD4F%2F20230820%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Signature=9b39e8f3418196887f49c7171fe8e5e7b071f099a654f499b60ba5a761132627&hash=250840af7a9674645263ae6d86ec4117a1aa3c8aa1886f8505fb8ed1b351f8f4&host=68042c943591013ac2b2430a89b270f6af2c76d8dfd086a07176afe7c76c2c61&pii=S0972629216313092&tid=spdf-7c7858ae-5bdf-4ec0-8a78-5f3ba2ec7bae&sid=2da163d78888714c762b1008be1a4dadf23fgxrqb&type=client&tsoh=d3d3LnNjaWVuY2VkaXJlY3QuY29t&ua=050b58065a04545b5401&rr=7f9c284cfcc4bafa&cc=ch

But we still did not find the Mason-Likar electrode placement with 3 leads in the specialized Indian journal about electrocardiography, and also nowhere else.