Get a different doctor, quick. Any doc who spouts such nonsense should be avoided at all costs because eventually you will end up on a med that you don't need and will harm you. For most people even with relatively high BP on a chronic basis, the best approach will usually be to change one's diet and exercise program, not to take meds. Meds are only necessary when the problem is chronic and dangerous. If you only get high BP when you're at the doc's office, and the rest of the time you're fine, you're fine. And no, this doesn't cause heart enlargement. What a crock. Are you sure your doc is a doc? I would recommend that if your BP goes up when you're anxious, and I'm not sure how anyone would accurately know that, but if it does, try meditation, exercise regularly, and get therapy for your anxiety so it goes away. Deep breathing and meditation can relax the system even if your brain is still churning out anxious thoughts. Relax.
I guess I'd ask how often are you nervous? Are you nervous outside of doctor appts? Are you taking your BP at home?
Paxiled makes a good point - how does one accurately know that your BP only goes up when your anxious? Is that because you are nervous at the doctor's, and it's high there? Is it not high anywhere else?
How high does it get? How long has it been getting that high? Is this a cardiologist or primary care doc?
Exercise, meditation, and diet are all good, as is therapy, but if you have a familial risk/history, that isn't always enough.
If you need a second opinion, get one, but we can't tell you to take or not take meds, and you haven't given us much info.