A cardiologist implants the CRT in the same place as a simple Pacemaker and three wires are used to monitor heart rate, detect heart rate irregularities and emit tiny pulses of electricity to correct them. A CRT is used to ‘resynchronise’ the heart.
An ICD is often used as a preventative measure for those who are potentially at risk of cardiac arrest in the future. If the heart is being at a potentially dangerous abnormal rate, the ICD will sense this and deliver an electrical shock to the heart, helping the heart to return to a normal rhythm.
Why might I need a CDT or ICD?
CRT:
We may recommend a cardiac resynchronisation therapy (CRT) device if you have moderate to severe heart failure and:
• Your heart's pumping chambers aren't working together
• You have an irregular heart rhythm, such as a left bundle branch block
• Your heart is weak and enlarged
• Medicines and lifestyle changes aren't working well enough
• You have complete heart block
A CRT device helps the heart pump more efficiently and can treat dangerously fast heart rhythms. It works by sending small amounts of electrical energy to the heart through insulated wires called leads.
ICD:
We may recommend an implantable cardioverter defibrillator (ICD) if you have a condition that increases your risk of a dangerous heart rhythm or cardiac arrest:
• History of cardiac arrest - You may need an ICD if you survived a cardiac arrest due to ventricular fibrillation.
• Abnormal heart rhythms - You may need an ICD if you have had episodes of ventricular tachycardia (VT) or ventricular fibrillation (VF).
• Heart conditions - You may need an ICD if you have a genetic condition that causes arrhythmia, such as congenital heart disease or Long QT syndrome. You may also need an ICD if you have cardiomyopathy, a condition that results in low heart function.
• Heart failure - You may need an ICD if you have heart failure and are at risk of developing a life-threatening heart rhythm.
• Other conditions - You may need an ICD if you have a neuromuscular disorder, such as muscular dystrophy, or cardiac sarcoidosis.
CRT:
Cardiac resynchronisation therapy (CRT) requires a minor surgery to place a device in the chest. CRT devices include:
• Cardiac resynchronisation therapy with a pacemaker (CRT-P). This device is for people who have certain stages of heart failure and irregular heart signaling. It sends signals that make the lower heart chambers beat at the same time. It helps the heart fill with blood properly.
• Cardiac resynchronisation therapy with a defibrillator (CRT-D). This combination device uses a pacemaker and an implantable cardioverter-defibrillator (ICD). It may be recommended for people with heart failure who also have a risk of sudden cardiac death. It can find dangerous heart rhythms and correct them. It can pace the heartbeat or shock the heart out of a dangerous heart rhythm.
Preparation:
You'll receive an IV line, and you will receive medicine to help you relax and numb the area where the device will be placed.
Insert wires:
We will insert wires into a vein in your upper body or thigh and thread them into your heart.
Create a pocket:
We will make a small incision and create a pocket under your skin to hold the CRT device.
Connect wires to device:
We will connect the wires to the CRT device and test them with an electric pulse.
The surgery to place the CRT device usually takes a few hours.
How the surgery is done may depend on the type of CRT device you're getting.
ICD:
An implantable cardioverter-defibrillator (ICD) is a small battery-powered device placed in the chest. It detects and stops irregular heartbeats, also called arrhythmias. An ICD continuously checks the heartbeat. It delivers electric shocks, when needed, to restore a regular heart rhythm.
You might need an ICD if you have a dangerously fast heartbeat called ventricular tachycardia or ventricular fibrillation. An ICD also may be recommended if you're at high risk of dangerous irregular heartbeats, usually because of a weak heart muscle.
An ICD isn't the same as a pacemaker. A pacemaker is a device used to prevent dangerously slow heartbeats.
There are two basic types of ICD:
• A traditional ICD is placed in the chest. Wires, called leads, attach to the heart.
• A subcutaneous ICD (S-ICD) ) is placed under the skin at the side of the chest below the armpit. It's attached to a sensor, called an electrode. The sensor runs along the breastbone. An S-ICD is larger than a traditional ICD. It doesn't touch the heart.
To place the ICD, the doctor makes a small cut in the skin in the chest area. One or more flexible wires called leads are inserted into a blood vessel near the collarbone. The doctor guides the wires to the heart. One end of each wire attaches to the heart. The other ends attach to a device called a shock generator. The device is placed under the skin beneath the collarbone.
The procedure to place an ICD in the chest usually takes a few hours.
Once the ICD is in place, your doctor tests it and programs it for your specific heart rhythm needs. Testing the ICD might require speeding up the heart and then shocking it back into a regular rhythm.
Depending on the problem with your heartbeat, an ICD could be programmed for:
• Low-energy pacing. You may feel nothing or a painless fluttering in your chest when your ICD responds to mild changes in your heartbeat.
• A higher energy shock. For more-serious heart rhythm problems, the ICD may deliver a higher energy shock. This shock can be painful, possibly making you feel as if you've been kicked in the chest. The pain usually lasts only a second. There shouldn't be discomfort after the shock ends.
Risks of cardiac resynchronization therapy may depend on the type of device used and your overall health.
Risks related to the device and surgery to place the device may include:
• Infection
• Bleeding
• Collapsed lung
• A hole in a heart chamber, causing fluid and blood to collect in the sac surrounding the heart
• Failure of the device
• Movement of device parts, which could require another procedure to correct
You usually stay in the hospital overnight after a CRT or ICD device. Make plans to have someone drive you home from the hospital.
Most people can go back to their usual activities after a few days. Your care team gives you specific instructions to follow. You might be told to limit upper body and arm activities. Your healthcare team also may tell you not to do strenuous exercise or lift heavy items for about a month.