You only have one heart and heart disease can range from trifling to, well, something much more serious. An angiogram might cost you £1K privately. It'll remove any doubt in what would already appear to be an ambiguous situation and it will give you a base line for the future. You may never need another one anyway, annual or less frequent cardiac ultra sounds being all that may be required.
The procedure is not pleasant but nor is it painful and requires nothing more than a few hours prone resting afterwards with no heavy lifting for a couple of days. You can ask for a little intravenous Valium which will have a wondrous effect upon your nerves at the time of the procedure. The implant does dissolve quite quickly and in the majority of cases there is no further complication.
Faced with even the slightest doubt as to the presence of heart disease, it's a no brainer isn't it?
(Not a medic but not a quack of a patient either.)