Since how long you are using these medicines?
Did you continously taking medicine since start of pregnancy?
Ok and thanks for your input.
Amniocentesis is another option to detect fetal birth defect. But this procedure has its own risks. In your case it is better to go for anomaly scan or fetal cardiac Doppler at 18-20 weeks.
In pregnancy blood volume increases which in turn lead to increase heart rate as well. So in your case some pericarditis and pregnancy physiological fluid over load is the cause of your increase heart rate.