Is this a proper treatment for Enlarged Aorta?

I was recently diagnosed with an Enlarged Aorta. The finding was quite unusual since I was not being seen for a heart condition, but evidently showed signs of some heart trouble (blood pressure lingering around 90/50 and pulse rate under 40 for almost 36 hours). My condition was discovered at 4.2 cm by ECG and I was given a walking stress test after BP and pulse stabilization 72 hours later. My stress test contraindicated the need for a pacemaker, and I was removed from my current BP regimen (Amlodipine and HCTZ) and placed on Diovan. My Board Certified Cardiologist said that the Diovan would significantly slow the progress of the enlargement. Does this sound right to anyone who has received this diagnosis. I am 44 years old, never had any heart problems, cholesterol of 173 with the good and bad in all the right places.