I had similar i had myocarditus (inflammation of the muscle around the heart) straight into hospital and on all the normal medication for a heart attack, including the ones to reduce blood pressure. my normal blood pressure is quite low, i am used to getting woozy if i stand up too quick. well every time they took my blood pressure the machine gave an alarm, my blood pressure was down to 70/50 in resting state, and every time they came over and asked if i was feeling ok. As it hadnt been proved to be myocarditis they kept me on those drugs until i went home, in the end i stopped taking them so i could stand out of a chair without fainting.