Please do a full check of your thyroid hormones, electrolytes in blood, EKG, Echocardiogram. It can be several things:
- tachycardia/palpitations from lyme - reversible
- POTS (a more serious tachycardia) - are these heart issues getting worse when you stand?
- partial or complete heart block - dying lyme bacteria in your heart release toxins that interfere with cardiac nerve conduction - it is reversible with treatment
- valve damage for lyme but more probably from bartonella - these are visible with Echocardiography - irreversible
- abnormal thyroid hormones - these can easily affect the heartbeat. Are these heart issues getting worse when you lie in bed, so horizontally ?
- abnormal electrolytes
Almost all lyme patients have some heart involvement and it is usually benign (reversible and not life threatening). Nevertheless the overwhelming majority of people that die from lyme disease they do die because of heart failure, so we should never take any heart problems easily and just ignore them ... If All the tests above find nothing then you will probably be fine.