You probably mean Premature Atrial Contractions, or PACs. PVCs are Premature Ventricular Contractions. They are "premature" because they are essentially beats that are occurring before they should. So while you should feel this: thump...thump...thump... What you might hear with PVCs or PACs is: thumpthump......THUMP. So what feels like a "skipped" beat actually isn't skipped, there's just a longer pause between two beats.
Many people experience both PACs and PVCs (I'm one of them), and most of the time this is all very benign, even though experiencing these premature beats can be uncomfortable. It's good you're seeing a cardiologist to rule out any problems, and most likely you'll be totally fine, you'll just need to learn to live with the darn things like so many of us do! If you do a search for PVCs, or even Google it, you will see exactly what I mean!
"Normal sinus rhythm" just means that your heart rhythm is normal.