Hi friend
Welcome to Health Care Magic
You say a resting pulse of 120 – and the Holter is normal?!
This rate is high.
Mitral Valve Prolapse alone could not account for this.
Laboratory work-up is needed - like blood counts, sugar, urea, electrolytes (potassium in particular),
thyroid (over-activity) etc. The treating doctor will suggest based on the situation.
There are advanced techniques of investigations of increasing complexity (some of them invasive), depending on need. The treating doctor may suggest them based on your condition. If there are no clues and if you are still bothered by it to the extent of interfering with life style – you have to go for more tests - like Electro Physiological Studies (EPS)
The first line medicine is generally beta blockers.
Metoprolol – slow release and small dose – will benefit Prolapse,
anxiety and missed beats. Your doctor will give proper prescription and follow up
Take care
Wishing you speedy recovery
God bless
Good luck