HCQ has been used as a prophylactic for Malaria for many decades, and a heart arrhythmia was never mentioned as a contra-indication, at least not when I checked a couple of months ago when I first heard about it as a possible "cure" (there were plenty of other quite serious side effects, that have already been mentioned previously on this thread). It has also been used successfully for Lupus disease, and I saw a very recent report that suggested almost every Lupus sufferer who were taking HCQ did not succumb to Covid (but obviously unclear whether they ere actually exposed to possible CV infection).
However, there now appears some evidence that when it's used for patients who are severely ill with Covid, that it is ineffective, and can lead to heart problems, possibly increasing the risk of death.
Most of the anecdotal reports where there were seen significant benefits of HCQ for Covid are where it was administered immediately the first signs are noted - even before a confirmatory Covid test, or even before any sign of Covid infection (such as the Lupus reports).
And of course, Trump has now recommended it as a prophylactic for Covid.
So, if there's no additional risk (of heart problems) when taking it as a prophylactic for Malaria, why then should there be ANY ADDITIONAL risk in taking it BEFORE Covid is detected, and I would like to see clinical trials continued on this basis.
I agree, that by the time Covid patients are suffering SEVERE symptoms, then it is perhaps too late anyway, but I believe that once patients are severe enough to be on a ventilator, then their chances of recovery are less than about 10% with or without HCQ.
"Peak Prosperity" have issued daily CV Update videos on You-tube, many concentrating on HCQ (among many other CV related topics). I'm not sure if I can link them here, but they're easy to find.
Check out the one from April 23rd, and it is also mentioned in a few later ones.