Devices Used in Cardiology (Pacemaker, Defibrillator)

The heart is the basis for all human life. Even a few missed heartbeats can signal a major problem, and keeping the heart on a regular schedule is one of your body’s top priorities.

When any of the normal electrical impulses that cause your heart to beat are interrupted or changed, this is called “arrhythmia” in the heart. Sometimes the heart will beat too quickly, sometimes too slowly, or sometimes with a different issue altogether – these all fall under the “arrhythmia” category. Heart arrhythmia can lead to problems with blood flow, some of which are serious and can be life-threatening.

For many people at risk of arrhythmia, or who are already suffering from this condition, pacemakers and defibrillators (Implantable Cardioverter Defibrillators, or ICDs) are some of the most common solutions. Pacemakers and ICDs are similar in many ways – they both help stimulate normal heart beat when the body is unable to. They work in different ways, however, and one might be more useful than the other for certain situations.

Pacemaker

A pacemaker is mainly for people who suffer from continuous issues with heart arrhythmias, rather than individual traumatic events like a heart attack. A pacemaker is a small, battery-charged device that’s inserted into the body to help maintain regular heartbeats.

A pacemaker is made up of two simple parts:

Generator: The battery power – it produces electrical impulses that can help trigger your heart if it’s having problems.
Wires: The parts that connect the generator to the heart

Most pacemakers go inside the body, and are inserted using a small surgical incision. In some cases, temporary pacemakers are used on the outside of the body for a short period of time.

A pacemaker replaces natural impulses in the body that can no longer perform their designated task. They stimulate the heart to beat and send blood elsewhere in the body, and speed things up if they’re moving too slowly.

Most pacemakers have sensors to stop them from firing if the heart is already beating quickly enough, but some also still function without these sensors. The ones that do have these sensors are called “demand pacemakers.”

There are three broad types of pacemakers:

1. Single chamber: Carries impulses from the generator only to the right ventricle (chamber) of the heart.
2. Dual chamber: Sends impulses to both the right ventricle and the right atrium, another heart chamber.
3. Biventricular: Stimulates the lower chambers of the heart, rather than normal pacemakers which stimulate the upper chamber(s).

Implantable Cardioverter Defibrillator (ICD)

ICDs are like pacemakers, but the big difference is that they’re designed for people who are at high risk of singular events like a heart attack – these devices don’t do as much consistent, day-to-day work as a pacemaker does.

From a technology standpoint, the two devices are almost exactly the same. ICDs are also battery-powered, are also placed under the skin, and also feed a generator into wires which connect to the heart and track heartbeat.

Rather than constantly stimulating a heartbeat, though, ICDs track heartbeat. ICDs are the final lines of defense against a catastrophic cardiac arrest or other life-threatening heart incident – if the ICD senses one of these events happening, it springs into action and activates the heart to keep you alive.

There are ICD units that have some of the same daily pacemaking properties as a standard pacemaker, but most are meant for serious problems that may come up. ICDs are recommended to people who have already had a serious incident in the past, or are at high risk of having one in the future. ICD patients may also have certain restrictions on diet, exercise and other habits. Your doctor will discuss these with you.