Sustained Sinus Tachycardia

I am a 22 year old female that has episodes of sustained sinus tachycardia in the 140s that last for 10-24 hours at a time which I have had for the last 3-4 years. I have dizziness, lightheadedness, left arm numbness, chest pain and shortness of breath on exertion along with the tachycardia. My cardiologist does not want to treat it because he says "it is just sinus tachycardia" but I am concerned that not treating could and has caused damage to my heart muscle. My normal resting heart rate is 75-80. Shouldn't I be started on a beta-blocker? Should I get a second opinion from another cardiologist?

[Brooke_38]

Hello...

Many cardiologists do not treat sinus tachycardia as this is usually a secondary response to an underlying issue.  Your Dr's focus should be concerned with the reasons for its development. Blood tests to check electrolytes(Potassium,Calcium&Magnesium) thyroid function may be checked as well determine the cause.

To "treat" sinus tachycardia is to identify the cause of sinus tachycardia and treat that.
Have you had any kind of testing at all?

[dinadog]

I started off with the same diagnosis and same results with doctors... One said, when you pass out let me know!!!! Can you imagine.

I now see a female cardiologist that yes does treat me on a beta blocker and now I am 45... I started full time meds at 40... and I was treated intermittently before that in my 20's and 30's on short term course.  Get on a two week holter monitor!