You don't mention the nature of the abnormality on your EKG.
In truth it sounds like you are stressing about a minor matter. Nonetheless, it makes sense to have this evaluated by a cardiologist to be certain. He/she will probably have you wear a holter monitor
or an event monitor to find out exactly what those rhythms are that are causing your palpitations. The results of that study will drive additional work-up or not. An initial echo is helpful but a second echo would not be the next step unless there was some reason to disbelieve the results from the first.
If the cardiologist tells you it is a benign condition, believe it and try to relax about the whole matter - I've never met a cardiologist who presumes and is casual about potential heart conditions.