For what it is worth, when I screened for my GILD trial it turned out that I had a extended QT phase (heart arrythmia). I figured it may have been due to a supplement I was taking. I stopped the supplement; the EKG went normal and I treated for 21 weeks w/ Harvoni.
Something like 5 weeks after ending the Harvoni treatment, and while recovering from TX related anemia I ran a 5K race and came in the top 25% of all finishers, while fewer than a half percent of participants were older than me.
EKG just recently checked; still OK. I am *mostly* still alive and well. : )