T Wave and bradycardia

[Buffie123]

I am female and 50(dxed with Hashimotos thyroiditis and crohns).  I have a history of abnormal EKG readings.  At age 23 I had a normal reading, and then 4 years later the tracing noted inverted t wave.  This pattern has continued w/o change over the years(although one of my last ecg said prolonged QT). At 32 when I had some chest pain (taking prednisone for Crohns at the time) I was admitted to a local hospital and was given no clear dx, since that left me concerned I went to Mayo in 1985 for evaluation(including radionuclide angiogram, holter monitor showed 52-106 range mean of 67). I was told the chest discomfort was noncadiac origin and some healthy people have t waves like this. I have renewed concerns about my heart. In recent years I have noticed a very low resting heart rate(48 upon awakening and in the 50s at rest during the day, it does rise with exercise etc. My GP commented I had the heartbeat of an athelete, slow and strong). I am not an athelete,in the past I have trained hard, but presently do not exercise due to fatigue. I am taking .1 mg of levoxyl for thyroid replacement and know a low heart rate can be due to the thyroid. I am also having perimenopause symptoms(hot flashes etc). My questions:

Does the change from my orig normal tracing at 23 to subsequent  readings at age 27 to now signify a problem?

Could the Crohn's dxed in my mid 20's have caused a change in my heart?

What does a prolonged QT signify (GP said it could be the clonazepam I was taking at the time)?

Shouldn't the thyroid replacement bring my heart rate to normal rate?

Thanks

[Cleveland Clinic]

1) Does the change from my orig normal tracing at 23 to subsequent readings at age 27 to now signify a problem?

Not neccessarily. T wave changes are notroiously non-specific and could be due to changes in heart rate, position and body habitus.  

2)  Could the Crohn's dxed in my mid 20's have caused a change in my heart?

Crohns can be associated with myopericarditis and some have hypothesized aortitis. I doubt the issues your discussing are related if all of your cardiac workup has been negative.

3) What does a prolonged QT signify (GP said it could be the clonazepam I was taking at the time)?

It is a period of time on the ecg representing electrical activity from the time the heart is contracting to the time it relaxes.  Sometimes this interval is prolonged due to various factors including inherited diseases as well as a number of drugs. Im not familiar with clonazepam causing this effect. The QT is often mismeasured, especially by the ecg machine calculation.


4) Shouldn't the thyroid replacement bring my heart rate to normal rate?

Some people have a slow heart rate. Thyroid supplementation can take many weeks to reach a steady state. If you are past this, the slow heart rate mey neot mean much.


good luck