Q: In Acute Aortic Dissection, why it is imperative to not only decrease the blood pressure but also the heart rate??

Answer:   In aortic dissection and aortic aneurysm, propagation of aortic dissection depends not only on the absolute blood pressure, but also on the velocity of left ventricular contraction. Target heart rate between 55 and 65 per minute is recommended.

Reference:  Varon, J.; Marik, P.E. The diagnosis and management of hypertensive crises. Chest 2000, 118, 214-227.