Thanks for posting your query.
With the available described symptoms, there appears to be possibility of Symptomatic extra beats which needs treatment.
All other investigations are normal as you have mentioned while presence of vibrating feeling, breathlessness, and anxiety
suggests treatment for symptomatic extra beats.
Extra beats may be physiological (fever
, use of coffee, tea and chocolates, exercise etc.) or due to heart disease
As you have normal stress test
there appears to be least chance of heart disease induced extra beats.
Yet you should take beta blockers or calcium channel blockers on written prescription as these are symptomatic.
You should also take benzodiazepines for relaxing your anxiety.
Dr. Mayank Bhargava