An implantable cardioverter defibrillator (ICD or AICD) is a permanent device in which a lead (wire) inserts into the right ventricle and monitors the heart rhythm. It is implanted similar to a single chamber pacemaker and the generator lays in the upper chest area and venous access is through the subclavian vein. Therapies are delivered in the form of anti-tachycardia pacing (ATP) or shocks to convert to sinus rhythm from sustained ventricular tachycardia or ventricular fibrillation, both of which are life-threatening rhythms.
Cardiac resynchronization therapy (CRT) is treatment to help your heart beat with the right rhythm. It uses a pacemaker to restore the normal timing pattern of the heartbeat.
The CRT pacemaker coordinates how timing of the upper heart chambers (atria) and the lower heart chambers (ventricles). It also works on the timing between the left and right sides of the heart.
When your heart doesn’t pump strongly enough, fluid can build up in your lungs and your legs. This is called heart failure. This condition can happen when the two bottom chambers (ventricles) of your heart don’t beat at the same time.
Your doctor may find out that you also need an implantable cardioverter defibrillator (ICD). This device helps fix serious heart rhythm problems. If you need this device, it may be combined with the CRT.
CRT therapy means you will need to have the pacemaker placed under your skin by minor surgery. Wires from the device are connected to the ventricles on both sides of your heart. The CRT device sends electrical signals to the ventricles to make them pump together the way they should. This type of electrical stimulation is called biventricular pacing.
CRT therapy works in about 7 out of 10 cases of heart failure. Not everyone with heart failure can be helped by CRT. For instance, if you have advanced heart failure, you are not as likely to respond to CRT. Overall, CRT may improve your survival, heart function, and quality of life if you have mild to moderate heart failure. It also improves your ability to exercise.