"Their heart may do this. Then it may come back and do this. There may be a space of time between it, then it will start again."
Sue Gentry is describing what's medically known as an arrhythmia, or irregular heartbeat.
Doctors have diagnosed her with atrial fibrillation, one of the most common rhythm problems in the heart.
"Atrial fibrillation is a rapid rhythm from the top chamber of the heart. Drives the top chamber about 400-500 beats a minute," says electrophysiologist Dr. Chakka.
He says treatment depends on the severity of the condition and the age of the patient.
For Gentry, who already has a pacemaker, alarming symptoms led her to seek medical attention.
"My feet started swelling and I had a hard time breathing," she says.
She was taken to the hospital and put on rhythm medicines. Doctors hope a combination of anti-arrhythmia medications and shock therapy will convert Gentry's heart back into a normal rhythm.
The procedure she is having is a simple one called cardioversion, where doctors attach medal pads to the patient's chest and administer low-energy shocks to trigger a normal rhythm.
If left untreated, arrhythmias can prevent your heart from pumping enough blood to your body and can raise your risk for stroke, heart attack and sudden cardiac arrest.
"Recognizing and treating it is very important," Dr. Chakka says. Many people walk into the emergency room with a stroke. That's the first time they are diagnosed with atrial fibrillation."
Patients who require an initial electrophysiology study usually have symptoms of shortness of breath, heart palpatations, fainting and chest pain - all symptoms to be aware of and talk to your doctor about.