Re: Advice please...
Noticing a carotid pulse is not uncommon, particularly in cases where athe phenomenon known as pounding heart is present and is entirely benign in this case. Rising from a chair or from a lying position always invloves orthostasis, or the body's compensation for changes in blood pressure necessary to maintain perfusion and is a normal physiological process. Negotiating stairs or other similar exertion will always produce an increase in cardiac force as a compensatory response.
Your tests indicate no pathology. If you are above the age of 40, then it's always a good idea to undergo a treadmill or chemical stress test, together with a general cardiovascular screening, if you have both personal and family risk factors.
Otherwise, it sounds as if you've allowed your worries to initiate some vigilence toward your physiology. Many autonomic processes go unnoticed until health anxiety is present, which subsequently gives rise to unfamiliar occurances that are misconstrued as possible warning signs.
You'll be fine.
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Best regards and Good Health