Last month, Kate Gillum told her first-grade class via Zoom that she had a squirrel heart and she had to go to the hospital to fix it.

That was the way she described the fast, irregular heartbeat she had. Doctors call it atrial ectopic tachycardia, a problem with the heart’s electrical system.

Kate’s case was the first time her doctor performed what’s called an ablation while a patient is on ECMO, or extracorporeal membrane oxygenation. An ablation uses radiofrequency to destroy the cells that are causing the irregular heart rhythm; ECMO uses a machine to circulate the body’s blood for the heart.

Doing this required the enhanced cardiac team that is now in place at Dell Children’s Medical Center of Central Texas and the new cardiac care unit that opened last June.

On April 22, Kate felt like she needed to throw up. "It hurt really bad," she says.

The 6-year-old’s heart was failing, as it had gone into an irregular rhythm and couldn’t keep up.

All that Wednesday night, Kate was trying to throw up, but there was nothing left in her stomach. Her mom, Adrian Gillum, slept beside her. Even though she was afraid to take Kate to the doctor the next morning because of COVID-19, she knew she had to call.

Kate just didn’t look right. She was pale, and she hadn’t wanted to eat all week.

Adrian Gillum, of course, wondered if this could be related to COVID-19, but the family hadn’t been anywhere.

Kate’s pediatrician was trying to keep morning appointments for well-check visits only during the coronavirus pandemic, but the office made an exception and gave the Gillums a 9 a.m. appointment.

The stay-at-home order might have been a blessing. There was no school to try to send Kate to that morning, no work for Adrian to try to get to. There was nothing stopping them from getting Kate checked out.

When the doctor’s office checked Kate’s heart rate and oxygen level, her heart rate was 225 beats per minute. A typical 6-year-old’s heart rate is 75 to 115 beats per minute.

Adrian Gillum says the pediatrician told her not to freak out but that she was calling an ambulance.

Inside the ambulance, the emergency medical technicians tried to slow Kate’s heart rate down by giving her two doses of adenosine. It didn’t work. They took her to the nearest children’s hospital, which was St. David’s Children’s Hospital in North Austin.

Doctors there also tried to treat Kate with adenosine, but it wasn’t working. They called the cardiac team at Dell Children’s, and Kate was transferred there by ambulance.

For this ambulance ride, Adrian wasn’t allowed to go with Kate. She called her husband, Matt, who quickly got care for 2-year-old Claire, picked up Adrian and headed to Dell Children’s.

Since the pandemic, area hospitals have had strict visitor policies. For children, only one visitor is allowed at a time, and that visitor has to be pre-screened for symptoms.

Matt Gillum waited in the parking lot while Adrian Gillum went inside.

She knew it was bad when she got to Kate’s room in the cardiac care unit and saw 11 people in the room.

They did an echocardiogram of Kate’s heart and saw the damage. Kate’s heart was still beating between 170 and 190 beats per minute.

Adrian Gillum says she was pretty calm until doctors told her, "This is very serious. Do you understand what is happening?"

"I started to panic," she says.

As Kate was getting sicker and sicker, she was becoming belligerent and angry. Her skin was getting more pale, especially her feet and hands.

"She started looking, with each hour, more and more ill," says Dr. Arnold Fenrich, the cardiologist who treated Kate.

As her heart was failing, they were talking about the possibility of Kate needing a ventricular assistive device or a heart transplant.

The hope was that they could get her heart under better control through medication so Fenrich could get her to the catheterization lab to be able to perform the ablation.

Her doctors decided to put Kate on a ventilator. Adrian Gillum says she stepped out of the room. "I can’t see that," she says.

She started to cry in the hallway, and the staff sent a chaplain to stay with her and made a compassionate exception to allow Matt Gillum to be inside the hospital with her.

They were shown to one of the family rooms, where Adrian Gillum says they were sobbing. They wondered what was happening. All they knew was that Kate really wasn’t doing well if the staff let both parents in the hospital at once during the pandemic.

Adrian Gillum says she began wracking her brain as to how this could happen. Kate wasn’t a kid who was sick a lot, and at all her well-checks, she had had a normal heart rate.

"How did we miss this?" "What did we not know?"

It turns out, nothing. This isn’t something genetic or with a known cause.

Fenrich explains that this type of tachycardia is not common and can be slow enough that someone might not have symptoms. "It might go unrecognized for a period of time," he says. "It can be months to years."

When it happens in kids, it’s more difficult to recognize because they might not understand the symptoms they are feeling or tell someone about them. They might just say they feel like their heart is going fast.

The Gillums began to settle into a routine. Adrian Gillum would stay with Kate for the day; then Matt would take the night shift. His mom came down from Fort Worth to bring Claire back with her. Her mom came to stay with them.

Doctors kept trying medications to slow down Kate’s heart, but it wasn’t working.

By Sunday, they decided to add another medication, and the Gillums were told that there was a risk that this medicine could cause Kate to worsen and need to go on the ECMO machine. The staff set up Kate’s room to be able to do emergency surgery if needed.

They allowed both parents to be together when they started the medication. After five or six hours, Kate seemed to be doing OK, and Adrian Gillium left for the night.

Kate’s heart rate began dropping, but not in a good way. Matt Gillum was told it wasn’t going well.

Then they started doing CPR on Kate.

Matt Gillum called his wife, crying. "You have to get here right now."

It was about 5:30 a.m. on April 26.

Adrian Gillum fell down the stairs at home trying to hurry to get to the hospital. Her mother had to drive her there as she hobbled on her ankle. Matt Gillum called her again to plead with her to get there.

By the time Adrian Gillum arrived, Dell Children’s made the exception and again allowed two parents to be with Kate. She was more stable and on ECMO, which would give them more time to try to get her heart rate under control.

They took Adrian Gillum down to the emergency room to check out her ankle, which wasn’t broken, and fit her with crutches and a brace. They had staff take her by wheelchair to where she needed to go.

That Monday, Fenrich knew he needed to do the ablation, and it would have to be done while on ECMO.

The staff had to be extremely well-coordinated to move a patient while on ECMO to the catheterization lab because of the tubing that is coming out of the patient and into the machine to do the job that the heart would normally do.

The ablation couldn’t be done in her room because the catheterization lab has all the electrophysiology equipment and the fluoroscopy.

"Getting her to the room took upwards of an hour," Fenrich says. "It’s just down the hall."

Then he had to find the source of the problem that is the size of a pinhead within the heart.

Fenrich threaded a catheter through Kate’s femoral vein in her leg up to the right side of the top chamber of the heart. They mapped the right side and didn’t find anything. It had to be on the left side.

Kate is one of 20% of people who have a hole between the two sides of the heart. That hole is supposed to be open when you are born and then close around your first birthday.

Fenrich was able to go through that hole instead of having to create his own hole to reach the left side, where he found the tiny spot that was causing all the problems. He destroyed that tissue with radiofrequency.

Kate was carefully watched, especially for the first 24 hours. Fenrich says that if she could stay in a normal heart rhythm during that first day, it would be extremely rare for her to have this problem again.

Two days later, a week after she first became ill, she was taken off ECMO. And then off the ventilator.

Kate, who had been asleep for nine days, was confused when she woke up.

"She said to me, ’Heart?’" Adrian Gillum says. "I nodded and got tears in my eyes."

Then Kate told her, "I feel better." And she started crying. Then she said, "I love you."

"It was so sweet," Adrian Gillum says.

"Everything kept continuing to progress," Adrian Gillum says. Kate was eating and drinking, then going for wheelchair rides, then walking around the hospital, then taking walks outside to look at the turtles in the healing garden.

On May 6, Kate got to go home. "It was amazing," Adrian Gillum says.

Even though it was a stressful time and an unusual time with visitor limitations, Adrian Gillum says they felt supported by the staff and their community.

Matt Gillum is a pastor at Austin Baptist Church. Word began to be spread around the world, and digital cards came in through Dell Children’s platform for the family.

Nurses who first took care of Kate would come by her room later and would have tears in their eyes, Adrian Gillum says. "They were so happy to see that she was doing well."

They would tell her, "This is a miracle." "This is amazing." "They wanted the best for her," Gillum says. "They had a personal investment in it."

The Gillums wanted to be able to thank the hospital staff, but, "How do you thank someone for saving your child’s life?" Adrian Gillum says.

This is the most gratifying case Fenrich has been involved with, he says. "To take someone where we were having conversations about a transplant or a ventricular assist device and fix them. Now they are back home and running around and playing. Just to be able to make that happen — to me, that’s extremely gratifying."

"The team of physicians, nurses, anesthesiologists knew how to take care of sick kids with heart problems here," Fenrich says. "Before we had the CCU (cardiac care unit) set up the way it is, we may not have had the same great result."

Dell Children’s has been rapidly expanding many of its departments, including cardiology, in the last three years. It will open up a 161,000-square-foot Dell Children’s Specialty Pavilion next April.

In May, it sent in its application to perform heart transplants.

"Austin is a big enough city and a city that deserves to have the best care, and we have that now," he says.