Heart of the Matter

The evidence appears to be accumulating that 'long Covid-19' infections can involve impairment of heart function (https://www.theguardian.com/world/2020/oct/04/long-covid-the-evidence-of-lingering-heart-damage). A number of studies have found that, even in people experiencing a 'mild' infection, there can be impacts on the heart in a relatively high percentage of cases. Sometimes these appear to be relatively short duration impacts but, in other cases, there seems to be lasting damage. Covid-19 (like related viruses, including MERS and SARS) can use enzyme systems to enter cardiac cells (these are higher in males than in females, perhaps accounting for the sex difference in infection-related heart disease). This causes inflammation and, in some cases, profound scarring. Covid-19 infections have been linked to ischaemic heart disease (where the blood vessels supplying the heart are narrowed, meaning that the organ receives insufficient oxygen to functon properly) and arrhythmic heart disease (where the heart beats too fast, too slow or irregularly). People who have heart conditions before being infected by the virus are especially prone to these complications. It has now been suggested that reports of 'breathelessness' in some long-haul patients results from a heart rather than a lung defect. The effects can be apparent in supposedly fit individuals (a professional basketball player, who had apparently recovered from a Covid-19 infection, had a heart attack in a training session and died). There are moves to check heart function in sports participants before allowing them to restart training and actual activity. These findings are one reason why it is too early to assess the impact of different strategies to deal with the pandemic. 'Herd immunity' (if it exists without a vaccine) may well result, eventually, in a lower transmission rate of the virus (and less economic damage) but there could be long-term consequences of the infection that will be with us for decades.