"asymptomatic" in the Covid context means "no external symptoms".

One of the quirks of this disease is that it does damage to the lungs and reduces oxygenation without any obvious external signs (see the reports from doctors of people texting when their blood oxygen levels were otherwise extraordinarily low) and there are now reports of people having lung damage when they otherwise did not present as sick.

So yes, it appears that it is possible to have long term damage even if it didn't seem that you were sick at first.

IIRC, this is because the aveoli in the lungs can still expel the CO2, but have a tough time with oxygen intake. It is CO2 build up that makes you feel distressed, not necessarily the lack of oxygen.

I've been interpreting the situation as:

-- most cases are asymptomatic.

-- some asymptomatic cases have e.g. detectable heart and lung problems.

-- some people have long term consequences.

...these points are not mutually exclusive.

Sure would be nice to have prevalence data on these!

Here's an anecdotal case of asymptomatic infection with lots of symptoms later:

https://twitter.com/FredTJoseph/status/1299395049684439042

Just search for asymptomatic covid cardiomyopathy

Also, it can be hard to tell when covid19 severity occurs as a result of undiagnosed preexisting heart conditions, versus causing heart conditions

Yes, but it is similat to the long term side effects from sars-cov-1, is in alignment with the pathology of moderate and severe cases, is in alignmnent with the type multi-organ damage observed... It might be hard to specifically tell for one person, but it seems very likely to me, speaking as a layman (and I believe there are academic papers that support it).

Asymptomatic or presymptomatic? There's a big distinction here.