What’s the difference between a pacemaker and a defibrillator?

“I tell people if pacemakers are like cruise control, defibrillators are like the airbag in your car.”

The concept of using pacemakers and implantable device to manage irregular heart rhythm patterns (arrhythmias) and heart failure started over 50 years ago. Since then, we have seen these devices improve patient outcomes from atrial fibrillation, arrhythmias, and heart failure. An estimated 1.5 million Americans have a pacemaker today. As a new generation of heart patients seek implanted devices to aid in the regulation and monitoring of the electrical system of the heart, some question having a small piece of technology implanted inside their chest.

Maryellen King is an Advanced Practice Nurse who specializes in cardiac device management and electrophysiology. As Manager of the Remote Monitoring Clinic at Capital Cardiology, she is an expert on how implanted technology continues to evolve to meet the needs of future heart patients. Maryellen has been working with patients who have had a pacemaker or defibrillator implanted for the past ten years. She often starts her visits by explaining the difference between the two devices.

What is a pacemaker?

Pacemakers allow most heart patients to participate in life fully. “Pacemakers are like cruise control on a car,” King explained. The device works on demand to regulate through electrical pulses that aid the heart to beat a normal rate. “They are meant for low or slow heart rates. People who have conditions where their heart rate is consistently low, or it’s likely to drop too slow or slow suddenly. They may be candidates for a pacemaker.” The device helps patients have a normal resting heart rate between 60-100 bpm.

The first pacemaker was implanted in 1958; it fired for three hours. About 400,000 pacemakers are implanted in the U.S. each year. Today’s devices have a lithium battery that can last 8-10 years, “maybe a few years more or less depending on usage,” King added. In size, pacemakers are small and relatively light. They are about the size of a half-dollar or smaller than pop-socket on a smartphone. Newer models weigh between 1 and 2 ounces. While there may be a slight bulge under the skin where the device is implanted, most patients have no problem wearing jewelry or clothing. Most patients don’t feel the pacemaker working. “Sometimes, during testing, when we’re trying to check some settings someone’s aware that we might be doing something, they can feel thumping. On an overall basis, no, people forget they have them.”

What is a defibrillator?

“A defibrillator is a life-saving device,” said King. Known as implantable cardioverter defibrillator or ICD’s, “they were developed in the 1980s. The reason people get defibrillators is that they’re at risk for life-threatening heart rhythm. Not just a slow heart rate, but a heart rhythm that could cause their heart to stop pumping blood suddenly,” she added. ICD’s work differently than a pacemaker, in that, they monitor heart rhythms and delivers electrical shocks to the heart known as defibrillation. The ICD current allows the heart to reset its electrical state and return to a regular beat where your heart pumps blood effectively. If you have a dangerously fast or rapid heartbeat, you would be a candidate for an ICD. “I tell people if pacemakers are like cruise control, defibrillators are like the airbag in your car. If you know you’re at risk for an accident and you’re driving a car you want the safety features, you want the airbag.”

As technology gets smaller, faster, and smarter, it also has added a layer of care for heart patients at home. Maryellen King also manages the Remote Monitoring Clinic at Capital Cardiology Associates. Her team oversees data collected from hundreds of patients with implanted devices that transmit patient data in real-time. “The remote technology that’s available now is usually a little monitor the size of a book, that transmits while the patient is sleeping,” King shared. Her team of nurses and remote monitoring technicians scan for alerts or urgent issues that require immediate attention. They can check for the device battery, usage of the pacemaker or ICD, along with changes in the heart rhythm. “When there are irregularities in their reports, we work with patients to see they are on the correct medications or anti-coagulation. In some cases, we will call the patient to follow up or send them to the hospital, depending on what is the most appropriate direction.”

Written by Michael Arce, Marketing Coordinator, Capital Cardiology Associates
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