### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
Hi,I was just reading one of the other questions and answers and noticed something that applied to me.  I have a history of SVT and have had a catheter ablation for it.  Since then, I have still had issues with heart racing (under SVT rates of 150, though) and my cardio thinks I have Innapropriate Sinus Tachycardia.  Am on 50 mg Inderal daily.  Toprol made my BP too low. The Q and A that caught my eye was the response from that doc telling someone to stay away from pools until their problem is dianosed.  The doc thought it might be SVT.  When I am in a pool for a period of time, I feel like I am starting to have some sort of heart issue and have to get out. Also, Ive noticed that, when Im riding in a car for more that 30 minutes, Ill get out of the car and feel a huge BP drop and feel like Im going to faint.  Also get migraines soon after.   Can you shed dome light on these things?

### output:

Dear, I'm glad to answer your question, but it shouldn't prevent you to visit your cardiologist .SVT is treated mainly by Isospin in much larger doses during the attack, then we release the patient on oral Isospin (240 mg / day). Also, we may let the patient on oral Propafenone 150 - 300 mg / day. Propafenone is more specific in arrhythmia than Isospin (calcium channel blocker) and Federal (Beta blocker) which have been used in lowering hypertension. So, I think you should change Federal to Propafenone 150 Thanks