SARS-Cov-2 binds to ACE receptors, which are present in cardiac muscle. The inflammation seems to be typical of how the immune system responds to this virus.
This is not directed to the comments above. Just FYI to anyone reading this thread, this type of myocarditis isn’t only seen in coronaviruses or specifically COVID-19. Rheumatic fever/Rheumatic carditis is well documented as a cause of molecular mimicry when dealing with Group A streptococcal bacterial respiratory tract infections. Similar things are seen with Coxsackie B virus causing pericarditis amongst other things. Other viruses have been implicated in the past. Some (in other sites) seem to think this a covid only issue.
Lower respiratory infections cause myocarditis extremely often. Subclinical myocarditis may well be universal in lower respiratory (lung) infections. Its one of the larger risk factors for heart attack- a flu vaccine can reduce your risk of heart attack for the entire year by 10-20%. Thats an insane return on investment.
When the lungs are infected, the heart works harder to pump blood through them. Virus-bearing blood flows directly from the lungs to the heart, and even if it isn't infected there will be a large local immune response. That means inflammation. Its nearly unavoidable once your lungs are infected. Even in young people, theres a huge difference between throat strep and lung strep (or flu)! It just isn't apparent until 20/30/40/50 years down the road.
I have to say, after all this is over I'll never brush off flu shots again.
I used to think of the flu as just "a cold, but worse", so I usually wouldn't bother to get a yearly flu shot. I saw it as five minutes of guaranteed unpleasantness vs an unlikely week of unpleasantness. My employer used to have CVS come by the office and give them to us for free; I didn't even have to pay and I still sometimes wouldn't bother.
Now via all these discussions I'm learning so much about how bad the flu can actually be for you in real, lasting ways. Really eye-opening.
Before I got COVID, I didn't even really realize that flu was asymptomatic so much, and I didn't know it was so much deadlier to the elderly. Not a good realization that I had been spreading without realizing.
That explains why I had heart palpitations last time I had flu. They continued for months afterwards too at random intervals with episodes of stabbing chest pain. Got told by multiple doctors I was fine and probably over stressed.
