Thanks for your question on Health Care Magic.
I can understand your concern.
Yes, you should definitely
consult cardiologist for this.
Heart rate of around 200 on walking is very high.
This suggests that your heart has to work very fast to meet the body needs in exertion.
Common cause for this is reduced blood supply to heart due to coronary artery blockade.
Atherosclerosis is the likely cause for such blockage.
So better to get done trade mill test (TMT) for the diagnosis of exercise induced
ischemia and if it is positive then you will need coronary
angiography for the diagnosis of coronary artery blockade.
Don't worry, with proper treatment, you will be alright.
Consult cardiologist and discuss all these.
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.