Thanks everyone!
On the heart ultrasound scan, it showed that Gustav have thickening of the walls in his left heart chamber, but no enlargements anywhere.
I am waiting for the vet to call back with the results of the plasma protein specification, since along with the bp on 230-250, the health blood tests showed Gustav had very high plasma proteins, he had 150 (normal 54-78) and very low albumin, he had 18 (normal 25-38). So he took a new plasma protein blood test and sent it away for specification. Gustav have had this before and last time it was the Immunoglobulines that was very high, but what is new this time is the very low albumine. He actually doesn't know what is causing it, and if the high blood pressure is connected to the proteins or to the thickening of the left heart chamber walls.