Is there a relationship between coQ10 use and reduction of SVT episodes (specifically focal atrial tachycardia), and if so what would be the recommend?

No, despite the ads, no clinical trials (sponsored by independent organizations) have ever shown any benefit for CoQ10 supplements, including for people taking statins. Only a single trial, sponsored by marketers of CoQ10 supplements, has been interpreted as showing slight benefit for people with advanced, class 4, congestive heart failure. Lots of marketing, science support for eicosapentaenoic acid; not for CoQ10.