High blood pressure affects different organs in different ways. Your heart pumps against the aorta which has the blood pressure. If the blood pressure in the aorta and in the arteries is high, the heart has to pump much harder and that will increase the thickness of the heart muscle.
And that can have adverse effects during the course of our life. It can increase the risk of heart attacks, it can increase the risk of heart failure, and the same high blood pressure can affect the arteries the heart itself which are the coronary artery's that means the arteries that supply the heart can get hard enough, can develop plaque and there is another risk factor for heart attacks as well.