Although both of these devices help correct heart irregularities, there are quite a few differences.
The heart of the average adult beats 60 to 100 times a minute, which is insignificant for most, unless you are a heart patient like Avery Hearvey.
"So his story is in 2002, he was having episodes where he was passing out or coming close to passing out," says Dr. Eleanor Kennedy. "He had an EKG during one of these episodes and the EKG suggested a dangerous heart rhythm."
On doctors' recommendations, Hearvey received an implantable cardioverter defibrillator (ICD) to regulate his heart.
Now he goes to St. Vincent Heart Clinic for his regular checkup on the device, also known as an interrogation.
"We learn if there is a problem with the lead wires that connect the pulse generator, which is where the battery is, whether there are any problems with the pace generator. And we also see how the patient is doing in terms of their heart rhythm," Dr. Kennedy says.
"He has not had any problems. He has gotten at least one shock from his defibrillator. So, he and many patients in our device clinic we feel are alive today related to the fact that they have a defibrillator."
The St. Vincent Heart Clinic follows 6,000 patients with implantable devices.
Like a pacemaker, a defibrillator maintains the correct heart rate by regulating heartbeats through electrical impulses. But unlike a pacemaker, when it detects the heartbeats are too fast, it shocks the heart back into a regular rhythm.
"Some people like to say it's like having an emergency room in your chest," says Dr. Kennedy.
The defibrillator is larger in size than a pacemaker and costs about five times as much. They are also highly regulated in terms of who can receive them.
"Patients need to be at high risk of needing the shock capability of the defibrillator in order to qualify to have one," she says.
The most common problem with ICDs is that they can sometimes give electrical pulses that aren't needed. Doctors can reprogram them or prescribe medicines so it occurs less often.
That's why it's a good idea to have your device regularly checked by your cardiologist.
ICD batteries have to be replaced every 5-7 years, and the wires may also have to be replaced eventually.