Because I have a left bundle branch block and heart failure and therefore on various drugs, long QT interval is something significant for me. A doctor needed to use an antibiotic for an infection that I had. He mentioned some antibiotics increase the QT interval which for me is not a positive. He chose one that did not. This is the first time that I became aware of this. This Wikipedia website explains a bit about this. en.wikipedia.org/wiki/Drug-...
If you are a person where the QT interval length is significant, you can get the App called CredibleMeds to check if a recommended drug is one you may wish to research.