If you don't test someone for coronavirus prior to the death (or even after), it doesn't get attributed to coronavirus

There is also a reverse problem. Some people are dying of heart attacks and are testing positive COVID-19, and are being counted even though it's unlikely the COVID-19 had anything to do with it.

What makes you think Covid-19 isn't killing those patients?

Because as far as we know it’s respiratory and asymptomatic for many days.

Someone who has a heart attack during the asymptomatic period was probably going to have one anyway.

How are asymptomatic people having heart attacks being coded as covid-19 deaths?

As far as I know, asymptotic people aren't even being tested for covid-19, because of the test kits shortage.

As we run short on tests it's likely that only the bad off will get tested.