A study found 40% of people who died of a sudden heart attack had enterovirus infection in their heart tissues.
Other studies which have linked enterovirus to heart attacks include this one, this one, this one and this one.
I suspect that the presence of enterovirus in the tissues is the smoking gun, suggesting enterovirus may be the triggering cause of around 40% of sudden heart attacks.
Given that there are about 225,000 fatal heart attacks per year in the US (ref here), that would mean enterovirus is killing around 90,000 people per year in the US alone, by precipitating fatal hearts attacks in often perfectly healthy people.
I personally have had direct experience of observing enterovirus causing heart attacks: some years ago when I caught a nasty coxsackievirus B4 infection (CVB4 is a virus in the enterovirus genus), as this virus spread to over 30 friends and family, it apparently caused four heart attacks in four previously healthy people — in one case a fatal heart attack. Two of these four heart attacks involved chronic viral myocarditis (ie, chronic viral infection of the heart muscle), which implicated the virus.
Thus I need no convincing of the ability of enterovirus to cause sudden myocardial infarctions in perfectly healthy people. For details about my Coxsackie B4 virus and the diseases it suddenly triggered in me, my friends and my family see here.
I know that association does not imply causation, but nevertheless there is enough evidence here to indicate we may have a killer on the loose, which is terminating the lives of 90,000 Americans per year, with similar death rates in other countries.
Death by sudden heart attack can be particularly cruel, as it can affect young as well as older people, and suddenly take away people's fathers, mothers, wives and husbands.
Yet in spite of this good evidence for the very real possibility that enterovirus is this monstrous serial killer, very little is done about it.
It would be quite feasible to create and introduce vaccines to protect against some of the most cardiotropic enteroviruses, which would probably include coxsackievirus B3, coxsackievirus B4, coxsackievirus B5, and some of the echoviruses. Such vaccines I suspect would likely dramatically reduce the incidence of sudden heart attacks (not to mention reduce the incidence of type 1 diabetes, Parkinson's, myalgic encephalomyelitis, and motor neuron disease which are also linked to coxsackievirus B).
Yet there is very little interest in creating enterovirus vaccines. Which is extraordinary, given how much effort is made to ensure people get vaccinated for say measles, a disease which would only kill a few thousand a year in the US if there were no measles vaccine.
But here we have a case of enterovirus potentially causing 90,000 deaths per year in the US, but nothing is done about it.
Go figure!