How Does Cardiac Resynchronization Therapy Work to Regulate the Heart?

If you have experienced heart failure or an irregular heart rhythm (also known as arrhythmia), you may be a candidate for cardiac resynchronization therapy (CRT). While it’s a mouthful to say, the procedure works to improve the heart’s function and efficiency. But what exactly is CRT and how can heart patients benefit?

For heart failure patients, cardiac resynchronization therapy is used to improve the heart’s rhythm and the symptoms associated with an irregular heartbeat. The procedure involves implanting a small pacemaker, about the size of a half-dollar, just below the collarbone. Three wires, or leads, connected to the device will monitor the heart rate to detect irregularities and emit tiny pulses of electricity to correct the rhythm. One lead goes to each of your ventricles. The third goes to your right atrium, one of your heart’s upper chambers.

Who is a candidate for CRT?

Cardiac resynchronization therapy is designed for heart failure patients with moderate to severe symptoms whose left and right chambers do not beat in unison. CRT works to improve the heart’s efficiency and increase blood flow. However, CRT is not effective for everyone and is not typically used for patients with mild heart failure symptoms. Causes of a weak heart include:

• Heart attack
• Damage to the heart
• Medications
• An inherited heart problem from your parents or a heart issue you have had since birth (also known as congenital).

What are the benefits of cardiac resynchronization therapy?

CRT works to help your heart pump more blood to your body. According to the American College of Cardiology, benefits can include:

• Making your heart more efficient
• Improving symptoms like shortness of breath
• Lowering the risk of abnormal heart rhythms in your ventricles
• Improve life expectancy
• Improving the ability to exercise

There are two types of cardiac resynchronization devices. One is called a cardiac resynchronization therapy pacemaker or, biventricular pacemaker. The other is a similar device but also includes a built-in defibrillator. This type is called a cardiac resynchronization therapy defibrillator.

How do cardiac resynchronization devices work?

A cardiac resynchronization therapy defibrillator is a special device for heart failure patients who are also at high risk for sudden cardiac death. While functioning like a normal pacemaker to treat slow heart rhythms, a CRT-D device also delivers small electrical impulses to the left and right ventricles to help them contract at the same time. This specialized device can also treat dangerously fast heart rhythms. If the device senses heartbeats that are too fast, it delivers a shock to the heart. This shock, or defibrillation, stops the abnormal rhythm.

It's important to talk with your doctor to see if cardiac resynchronization therapy is right for you. CRT is often combined with other treatments.