Since, 56, of St. Charles, Mo., felt healthy until her fainting spells began. At first the episodes were rare, but before long, Since passed out once or twice a week. Then, once or twice a day.

She was understandably alarmed. For more than a year, doctors were looking for a neurological cause for her fainting and found nothing.

Since noted that many of her episodes took place after exertion, such as when she was climbing stairs or changed position, even after rolling over in bed.

"I told my husband that it had to be my heart or lungs," Since says.

Finally, she had an echocardiogram that resulted in an immediate hospitalization and a frightening diagnosis, pulmonary hypertension (PH), or elevated blood pressure in the pulmonary arteries.

The condition can be progressive, debilitating and fatal. Until a few years ago, there were few effective treatments. Now, a handful of centers in the U.S. offer specialized care for PH patients with new treatments that reduce patients'' symptoms and restore quality of life. Washington University pulmonologist Murali Chakinala, MD, heads the pulmonary hypertension program at Barnes-Jewish Hospital.

Since was transferred to the intensive care unit at Barnes-Jewish Hospital, where she became Dr. Chakinala''s patient. Her heart was dangerously enlarged and extremely weak. During a three-week hospitalization, she had an indwelling vascular catheter placed and learned to operate an IV pump that constantly delivers life-saving Flolan, a vasodilator that relaxes the blood vessels of the lungs and strengthens heart function.

Though the therapy is complex — requiring Since to mix her medication daily and care for the pump — it has allowed a return to a normal lifestyle, even visiting her sister in the thin atmosphere of Colorado.

"I''m doing so well now," Since said. "I look back and it almost seems like a different person who was so sick. Dr. Chakinala and the whole team really came through for me."