It's the whole coronary system not just the heart. It also comes with the same swath of possible symptoms as most stimulants including high blood pressure, stress/anxiety, etc.

That said, IMO the biggest issue is the litter. Used pouches should go into the trash can and away from animals.

I don't think the US has strict regulations on the ingredients... I don't know why, likely lobbyist behavior, but also I think people just accept that if you smoke you don't give a shit and it's unhealthy by default, so it's not a big deal if they add chemicals.

Which becomes more ridiculous with nicotine pouches for this reason. Nicotine isn't cancerous, so it would be super shitty to add carcinogens in the pouches and then claim it's a tobacco product so you should expect it.

it’s the safest delivery method.

hitting your head with a 2 pound hammer is safer than hitting your head with a 10 pound hammer.

Vaping is very possibly much less unhealthy than chewing tobacco, but of course we don't have long term studies yet

well you are putting it in your mouth, so you're effectively swallowing parts of it.