Try Hypnosis, breathing exercises (I bet thats fast too)
Above all forget it and enjoy yourself.
A little harsh,and, if I may say, patronising!
Some people (i'm one of them) are more aware of their heart beating than others. I went for months with 'palpitations' dismissed by doctors as ectopics before I had an episode of Atrial Fibrillation that got my heart going at a recorded ventricular rate of 280 BPM.
This resulted in an ablation procedure, a follow up two months later, and ongoing evaluation.
The 'it's all in your head' brigade drive me nuts. If it hasn't happened to you then you don't understand!
Rob, it may be worth a longer ECG holter, i.e 48-72 hrs to see what's really happening when you get these periods of abherrant behaviour. It is concerning when they happen and in my case nearly caused lasting muscle damage.
Not to mention it was bloody frightening!