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Cardiac Resynchronization Therapy


What is cardiac resynchronization therapy?

Cardiac resynchronization therapy (CRT) is a procedure to implant a device in your chest to make your heart’s chambers contract in a more organized and efficient way. 

Cardiac resynchronization therapy uses a device called a biventricular pacemaker that delivers electrical signals to both of the lower chambers of your heart (ventricles). The signals tell your ventricles to contract at the same time, maximizing the amount of blood that’s pumped out of your heart.

Sometimes the device also contains an implantable cardioverter-defibrillator (ICD), which can deliver stronger electrical shocks if your heart rhythm becomes dangerously erratic.

Why is it done?

Cardiac resynchronization therapy is a treatment for heart failure in patients whose ventricles do not contract at the same time.

If you have heart failure, your heart muscle is weakened and may not be able to pump out enough blood to support your body. This can be worsened if your heart’s chambers are not in sync with each other.

Cardiac resynchronization therapy delivers electrical signals that cause your heart to beat in a way that maximizes the amount of blood that’s pumped out of your heart. This treatment may reduce your symptoms of heart failure and reduce your risk of heart failure complications, including death.

What are the types of cardiac resynchronization therapy devices?

The types of cardiac resynchronization therapy devices include:

Cardiac resynchronization therapy with a pacemaker (CRT-P). The device used for cardiac resynchronization therapy has three leads that connect the pacemaker to the right upper chamber of your heart (right atria) and both lower chambers (ventricles).


Cardiac resynchronization therapy with an ICD (CRT-D). People with heart failure who also have a risk of sudden cardiac death may benefit from an ICD that can detect dangerous heart rhythms and deliver a stronger correcting shock of energy than a pacemaker can deliver. In these cases, a cardiac resynchronization therapy device that works as both a pacemaker and an ICD may be recommended.


What is fluid monitoring for heart failure?

Some pacemakers/defibrillators have a fluid monitoring feature that may detect signs of worsening heart failure/ fluid overload. This feature works by sending electrical impulses through the heart chambers and lungs. When fluid builds up, the impulse traveling across the heart and lung cavities speed up. For heart failure patients, this fluid could be a sign of worsening heart failure. This device data can be transmitted to a doctor’s office, where the physician is able to make a clinical assessment of the patient and may provide for a more timely clinical intervention.

How do I get ready for the insertion of a CRT device?

You should discuss all the risks and benefits of the procedure with your doctor. You have to be fasting for 8 hours prior to the procedure. If you usually take medicines in the morning, ask your doctor if you can take them with a sip of water. Your healthcare team may ask you to stop taking any medicines that thin your blood several days before the procedure. If you take medicines for diabetes, ask your doctor to help you adjust your dose around your surgery. 

What happens during insertion of a CRT device?

  • In the procedure room you will lie down on an X-ray table.
  • An intravenous (IV) line will be put into your hand or arm. Your healthcare team will give you fluids, antibiotics, and pain medicine through this line.
  • Your team will watch your heart, blood pressure, and oxygen level.
  • Your doctor will give you medicines to help you relax or fall asleep. The doctor will also numb the area where the device will be placed. This is usually just under your left collar bone (clavicle).
  • Your doctor will make a small cut (incision) and create a pocket under the skin. This pocket will hold the wires and computer battery pack for the CRT.
  • Your doctor will put IV lines in the large vein that feeds your heart. CRT wires (leads) will be placed into the vein and fed into your heart. Special X-rays will be taken to make sure the leads are in the right place on both sides of your heart.
  • Your doctor will test the leads with an electric pulse.
  • If the leads are in the right place and working as they should, they will be attached to the CRT pacemaker. Your doctor will put the pacemaker through the incision and under your skin.
  • Your doctor will then close the incision with sutures and apply a dressing.

Is CRT therapy effective in every patient?

CRT therapy works in about 7-8 out of 10 cases of heart failure. Not everyone with heart failure can be helped by CRT. But in most patients, CRT may improve your survival, heart function, and quality of life. It also improves your ability to exercise.

What are the risks of cardiac resynchronization therapy?

CRT is not considered a major or dangerous type of procedure. But like all surgery, it carries some risks. They include:

  • Reaction to the anesthesia
  • Swelling or bruising in your upper chest area where the CRT device is placed
  • Bleeding
  • Infection
  • Heart rhythm problems
  • Movement of the device or the device wires. This may require a second surgery.
  • Mechanical problems with the CRT device

What happens after the CRT device is inserted?

You will be moved to the recovery area. You will stay there until the relaxing medicine has worn off. A healthcare provider will give you pain medicines as needed. You may need to stay in the hospital for a day. After you leave the hospital, it will be important to follow all of your doctor’s advice and keep all follow-up appointments. The following is what you can expect once you are home:

  • You should be able to follow your normal diet.
  • You may need to limit activities such as lifting heavy weights, straining, and stretching for the first 6 weeks. Ask your healthcare provider when you can return to specific activities.
  • Keep the dressing clean and dry until your healthcare provider tells you it is OK to remove the dressing and take a shower.
  • Check your incision area for any signs of infection. Let your healthcare provider know if you have any fever, redness, soreness, discharge, bleeding, or swelling.

What are the likely long-term instructions for living with your CRT device?

Make sure to have your doctor check the functioning of your device regularly. This should be done once every 3-6 months.

Carry a CRT pacemaker identification card and let all your caregivers know about your device.

Your pacemaker battery will last for about 5 to 8 years. Your doctor will be able to tell about 6 months before the battery runs down. Replacing the CRT pacemaker is a minor procedure.

It’s a good idea to keep all electrical devices about 6 inches away from your CRT pacemaker. They can interfere with its function. You may need to stay away from devices that have strong magnetic fields. These include electrical generators and appliances like microwaves. Talk with your healthcare provider if you have any questions about what to avoid. Most X-rays and metal detectors are safe, but you should avoid metal wands used for airport screenings and MRI imaging tests.

CRT Discharge Instructions

Wound care instructions:

  • Keep the area where the pacemaker/ICD was inserted clean and dry.
  • Do not get the pacemaker/ICD incision wet for at least 7 days.
  • If you have aquacel (skin colored) dressing over the incision site, it is waterproof. You can take shower with the dressing on. The dressing needs to be removed after 1 week.
  • If you have steristrips (small white paper tapes) over the incision site, the incision site must be kept dry for 1 week. Either you can use wet towel or you can use large piece of Saran/plastic wrap over the incision site while you take shower. Remove Saran/plastic wrap after shower so that the incision site is dry and leave it uncovered at all other times. You can start taking shower regularly after 1 week. The steristrips will fall off on their own or the doctor will remove them at your follow up visit.
  • Do not submerge the wound under water during the healing period for 6 weeks.

Notify your physician if:

  1. You notice unusual redness or swelling at the site,
  2. Drainage from the wound,
  3. A fever of greater that 100.5 or chills.
  • Avoid extreme pulling, pushing or lifting motions for 6 weeks from the date of the procedure, (such as placing your arm over your head without bending at the elbow).
  • No heavy weight lifting greater than 10 lbs.
  • No golf or swimming for 6 weeks.
  • You will need to be seen in 1-2 weeks to for a wound check.
  • If you do not have an appointment scheduled, call 602-698-5820 to schedule an appointment for a wound check.

Things you cannot do:

  • Arc welding can adversely interact with your device and cause an inappropriate shock.
  • Do not lean over a running car engine with the hood up. The electrical signal can be misinterpreted by the device. Being next to a running car should not adversely affect your ICD.

Things you can do:

  • You can have X-rays and CT scans
  • Normal household items such as microwave, TVs, refrigerators, ovens, saws, dryers, washers, electric blankets and computers DO NOT adversely affect your ICD.
  • Cellular phones do not, in general affect your ICD. It is recommended you use the ear opposite the device. Blue tooth is OK.

MRI Safe Pacemaker:

Most new PPM/ICD implants are now MRI compatible. If you need an MRI, please obtain clearance through your EP physician prior to ordering the MRI.

Traveling with your device:

  • Immediately following your surgery, you will receive a temporary identification card. A permanent identification card will be sent to you by mail in 8 weeks. Keep this card with you at all times.
  • Tell the airport personnel that you have a pacemaker-defibrillator, show them your ID card and they will wand everything but the device. X-ray will not harm your device.

What if I get shocked at home?

  • If you receive 1 shock and you feel fine, remain calm and call 602-698-5820 to be seen in the next 48 hours. Your device will store the information, so we will be able to review what caused the shock.
  • If you receive more than one shock, please call 911 to seek emergency medical attention.
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