Pacemakers and Defibrillators

Some arrhythmias are life-threatening and can increase the risk of heart failure, stroke, or death. Implantable pacemakers and defibrillator devices can help keep your heart in rhythm.

Experts at the AHN Cardiovascular Institute use the latest devices to treat abnormal heart rhythms.


Your physician may recommend a pacemaker if you have symptomatic bradycardia. If you have an abnormally slow heart rate and feel poorly as a result, a pacemaker can help regulate your heart rate

Types of pacemakers

Depending on your specific needs, your physician may recommend one of the following:

Transvenous pacemakers

Transvenous pacemakers use low-energy electrical pulses to stimulate a heartbeat. They are most often placed on the chest wall, below the collarbone, and wires connect to the heart. Depending on your specific needs, one, two, or three wires may be needed.

Leadless pacemakers

In certain situations, a leadless pacemaker may also be considered. Leadless pacemakers have more limited pacing capabilities but do not utilize wires because the contact point is built in. The device is so small that they are embedded entirely inside the heart. In fact, they are so compact that, when the battery is low and you require a new pacemaker, the old one may not need to be removed.

Implantable cardiac defibrillators (ICDs)

Implantable cardiac defibrillators, or ICDs, are similar to pacemakers but are modestly larger and have the ability to treat dangerously fast heart rhythms by delivering a high-energy shock to reset the rhythm. Sometimes a dangerously fast rhythm can be paced back into normal rhythm, with shocks reserved as backup. Most defibrillators are implanted similarly to transvenous pacemakers, on the chest below the collarbone, with leads attached inside the heart. Most defibrillators can also function as pacemakers and, depending on your medical situation, one, two, or three leads may be implanted. There is also a type of ICD called a subcutaneous ICD, with a single lead that is tunneled under the skin and placed around the heart. This type of device has limited pacemaker functionality, but it has other benefits. Deciding on the best type of device for you is an important discussion to be had with your cardiologist or electrophysiologist.

Pacemakers and defibrillators generally have two main components: the pulse generator, which houses the battery and computer circuitry, and the leads. The batteries in the pulse generator generally last seven to 10 years in an ICD and nine to 12 years in a pacemaker, though there is some variability depending on the specific device you have and how often it paces, or if you have any shocks. When the battery is low, another procedure is required to give you a new pulse generator. Leads are designed to last decades and, as long as they’re functioning well, they don’t need to be changed at the time of a new pulse generator. Technology is constantly improving, so the battery life on your next pulse generator will likely be even longer.

What to expect

How to prepare

Before having an ICD implanted, you’ll be asked to avoid food and drinks for at least eight hours before your procedure. Your doctor will provide other detailed instructions on how to prepare, including whether you should avoid specific medications.

How pacemakers are implanted

Pacemakers and ICDs are usually placed in the electrophysiology lab. In some cases, the catheterization lab or the operating room may also be used for implantation. You will be sedated by an anesthesiologist and local anesthesia will also be used over the incision site. Most people can be safely discharged to go home the same day as the implant procedure. However, some patients may be required to spend the night in the hospital to ensure the device is working properly.

To implant the device, a small incision is made in the skin below the collarbone. The lead or leads enter a vein near this location and follow that vein down to the heart. Once each lead is in place, it will be tested to ensure it’s working appropriately. The leads connect to a pulse generator, which includes the battery and computer c