PH involves both the heart and lungs, but unless it is caused by another disease, it appears to start in the lungs. The blood vessels that supply the lungs constrict and make the walls thicken and unable to carry as much blood. Like a garden hose with a kink in it, pressure builds up and backs up. The heart works them harder, trying to force blood through. Eventually it cannot keep up and there is less blood circulating through the lungs to pick up oxygen.
Patients become tired, dizzy, and short of breath.
Swollen ankles and legs, chest pain, and heart palpitations are also common symptoms. Without treatment, PH is usually fatal within three years of diagnosis. In the United States, about 300 new cases of PH are diagnosed each year. The greatest numbers are in women between the ages of 21 and 40. In about 6 percent to 10 percent of cases, PH is genetic.