Venu 3/3s - Is there a planned release date for a 'Software' update (6.23?) that will allow use of the ECG app?

I think ECG will only start if they get the approval of the USA FDA. Until then I doubt they will release it, even for other countries. I like to be wrong though. 

Well… Garmin is the slowest major vendor on this topic. So far, they delivered ECG on ONE device, for ONE country. And regulations are not an excuse. Some other companies were able to go thru the approval process on several continents in record time. I suppose it's more a matter of will…

I would love to be proven wrong (perhaps the total silence on next betas, for all devices, is a good sign), but I wouldn't hold my breath if I were you.

A good explanation of ECG on Garmin watches, specifically the Venu 3 - Garmin Venu 3 In-Depth Review: More Sleep Analytics, Power Meters, and More! | DC Rainmaker

Regarding the removal of ECG functionality, this piece is a bit ‘complicated’. The sorta-short version here is that when Garmin switched from the existing ELEVATE V4 sensors (with some added ECG-related hardware on the Venu 2 Plus), the new Garmin ELEVATE V5 isn’t yet certified for ECG. Technically speaking, Gamin doesn’t likely have to recertify between these two sensors within the FDA SaMD program, but practically speaking Garmin has always been a very risk-averse company. Thus, as things stand at this moment, the Venu 3 does not have an ECG feature enabled on it. However, this new sensor (same as on the Epix Pro & Fenix 7 Pro) does have the correct required hardware for ECG, if/when Garmin were to enable such a feature. Garmin officially cannot state if or when the unit would ever get such a feature enabled, thus, if you really really really need ECG, then I’d wait until something changes. But as Garmin has stated in the past, they are keenly aware of how important ECG is on smartwatches going forward. And if Garmin were to be doing some revalidation, they’d be able to do so far faster than the first rounds of approvals, as they’d only need to prove it’s “substantially similar” to that product.

That is very disappointing if true. Why then has it been available on Fitbit Sense for a considerable time?

ECG is right now available in 4 countries. If you reside in one of those, you will get it in the Garmin Connect. If not, you have to wait for the approval. Many have reported that by changing region, they get ECG functionality (formatting the watch and doing all from step 1), but I can't comment if that works or not. 

Sounds like a plan, what countries would these be and is there any downside to doing that in everyday use ?

Garmin ECG supported countries: https://support.garmin.com/en-US/?faq=QssFZHtIOfAYNSSmzXNwY9

The downside to using the ECG app every day? I guess none. You can do it every hour too. But it can consume battery, just keep an eye on that.

They are not 100% accurate, all watch ECGs are single-lead ECGs, and they are not known for their accuracy. Typical hospital ECGs are 6-lead or 12-lead ECGs.

Thanks, actually I was wondering about downsides of using your watch outside of your actual region ?

There are no downsides.