Anything related to heart is to be concerned of. since you have additional cardiac problems and blood pressure it increases your risk for other troubles like atherosclerosis(blood vessel blocking disease). So to my opinion better get a Cardiology consultation. If they find any thing wrong with your heart(flutter most likely arterial) and a treatable cause then they will cure. An ecg with Echo will be done at first with a Thyroid
function test. It could be even because your BP medication
make you hypovolaemic which is causing all the compensatory tachycardia
and flutter. Where they will change the medications as needed.Hope you find my suggestion valuable. Feel free for any more quarries.