About three years ago, Amy Hoffman began noticing that her heart was speeding up for no reason.

"I was feeling like my heart was constantly racing," she said. "It happened a couple of times a week, with chest pains."

She knew 120 heartbeats a minute was too fast. Over time, the condition got worse, and it would jump to 200 heartbeats on very short walks.

"I started to collapse in the hallway at work," she said. "My heart rate would not go down."

She was seeing a cardiologist for a sticky heart valve and brought up the condition.

The doctor tried beta blockers to slow down her heart, but the medicine made her blood pressure drop so low that she got dizzy when she stood up.

Hoffman had developed "inappropriate sinus tachycardia," which means her heart would beat too fast at the wrong time.

A small organ called a sinus node sits at the top of the heart and works like a distributor on an automobile engine. The sinus node sends electrical signals to the heart so that it beats. Sometimes the sinus node goes haywire.

It's not life threatening, but it can cause problems that can threaten safety and life, said Dr. Ali Mehdirad, professor of cardiology at St. Louis University. "If she passes out and falls and hits her head or something else, that can be life-threatening.

"When we have short circuits, then we can delete that from the electrical system by cauterizing it, like cauterizing a mole," Mehdirad said.

He threads a catheter through blood vessels into the heart. A mapping procedure finds the trouble spots on the node, he said. Then a hot probe burns and blocks the errant connection.

"We just delete the abnormalities of the wiring," he said. "Then the sinus node functions normally."

The procedure comes with a risk of killing the sinus node, he said. "Then the patient needs a permanent pacemaker. She (Hoffman) is one of the 70 percent who doesn't need a pacemaker."

The cause is uncertain, Mehdirad said. All the medical community really knows is sometimes the organ malfunctions, he said.

Hoffman said she knew the risks, but, "I was tired all the time and got to a point where I couldn't stand," she said. "My heart rate was over 200 and the heart muscle doesn't like that. I was afraid of heart failure."

When she wasn't working, "I was home on the couch sleeping."

'TON OF ENERGY'

She had the procedure in April. She needed only an overnight stay at the hospital.

"It took a couple of days to kick in, but I could tell right away there was a change," she said. "No chest pains, a different outlook on life.

"I had a ton of energy the next week. I was planting a garden, carrying bags of soil and I could do that for hours.

"I could go on long walks again. I have three dogs who like to walk."

She also has taken up running, mainly around the neighborhood. "I don't calculate miles; I'm just glad to be able to do it," she said.

Mehdirad said Hoffman was fortunate that she was diagnosed with the condition before she was misdiagnosed.

Inappropriate sinus tachycardia is often misdiagnosed as anxiety disorder, panic attack or depression, he said. Ironically, the misdiagnosed person ends up worried, anxious and depressed because the condition doesn't clear up, he said.

"Usually, young women have the condition," he said.

In many cases, women have been placed on nerve pills; anxiety pills, he said. "And they didn't need it."

He said he "gets two to three patients a month with the condition, but he's certain that more remain undiagnosed or misdiagnosed.

"In general, a young healthy, and otherwise healthy, female — 20 to 50 years old — has episodes of pounding, racing, fast heart rhythm," Mehdirad said, "and the general practitioners have not been able to take care of it. The patients need to be considered for inappropriate sinus tachycardia."

Still, "patients are getting more educated," he said. "After Miss Hoffman had her (procedure), two weeks later a young woman was in my office. She'd read Miss Hoffman's story on Facebook."