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Why It’s Done

What is Cardiac Resynchronization Therapy?

Cardiac resynchronization therapy (CRT) is used to treat the delay in heart ventricle contractions that occur in some people with advanced heart failure.

Heart failure means the heart’s pumping power is weaker than normal. With heart failure, blood moves through the heart and body at a slower rate, and pressure in the heart increases. A delay between the contraction of the right and left ventricles often occurs with heart failure, so the walls of the left ventricle are unable to contract at the same time.

The CRT pacing device (biventricular pacemaker) is an electronic, battery-powered device that is surgically implanted under the skin.

The device has 2 or 3 leads (wires) that are positioned in the heart to help the heart beat in a more balanced way. The leads are implanted through a vein in the right atrium and right ventricle and into the coronary sinus vein to pace the left ventricle.

Description

When your heart rate drops below the set rate, the device generates small electrical impulses that pass through the leads to the heart muscle. These impulses make the lower chambers (ventricles) of the heart muscle contract, causing the right and left ventricles to pump together.

The end result is improved cardiac function.

CRT Device

The CRT device has 2 or 3 leads that are positioned in the:

  • Right atrium
  • Right ventricle
  • Left ventricle

Electrical System of the Heart

The atria and ventricles work together, alternately contracting and relaxing to pump blood through the heart. The electrical system of the heart is the power source that makes this possible.

Normally, the electrical impulse begins at the sinoatrial (SA) node, located in the right atrium. The electrical activity spreads through the walls of the atria, causing them to contract.

Next, the electrical impulse travels through the AV node, located between the atria and ventricles. The AV node acts like a gate that slows the electrical signal before it enters the ventricles. This delay gives the atria time to contract before the ventricles do. From the AV node, the electrical impulse travels through the His-Purkinje network, a pathway of specialized electricity-conducting fibers. Then the impulse travels into the muscular walls of the ventricles, causing them to contract. This sequence occurs with every heartbeat (usually 60-100 times per minute).

Benefits of CRT

CRT improves symptoms of heart failure in about 50% of patients who have been treated maximally with medications but still have severe or moderately severe heart failure symptoms. CRT improves survival, quality of life, heart function, the ability to exercise, and helps decrease hospitalizations in select patients with severe or moderately severe heart failure.

CRT & ICD Therapy

Some patients with heart failure may benefit from a combination of CRT and an implantable cardiac defibrillator (ICD). These devices combine biventricular pacing with anti-tachycardia pacing and internal defibrillators to deliver treatment as needed.

The CRT/ICD combination devices:

  • Resynchronize the heartbeat
  • Slow down an abnormal fast heart rhythm
  • Prevent abnormally slow heart rhythms
  • Record a history of the patient’s heart rate and rhythm

Some CRT and ICD combination therapies have an internal monitoring device inside so your doctor or nurse can track your heart rhythm and heart function, such as the pressure in areas of your heart.

You may be asked to use a telephone to transmit data electronically from your device to a computer server so your doctor or nurse can monitor your condition.

Monitors Used During the Procedure

  • Defibrillator/Pacemaker/Cardioverter: Attached to one sticky patch placed on the center of your back and one on your chest. This allows the doctor and nurse to pace your heart rate if it is too slow, or deliver energy to your heart if the rate is too fast.
  • Electrocardiogram/EKG/ECG: Attached to several sticky electrode patches placed on your chest as well as inside your heart. Provides a picture on the monitors of the electrical impulses traveling through the heart.
  • Blood pressure monitor: Connected to a blood pressure cuff on your arm. Checks your blood pressure throughout the procedure.
  • Oximeter monitor: Attached to a small clip placed on your finger. Checks the oxygen level of your blood.
  • Fluoroscopy: A large X-ray machine will be positioned above you to help the doctors see the leads on an X-ray screen during the procedure.

FAQS

Yes, CRT can help improve your ejection fraction (EF).

EF is the measurement of how much blood is being pumped out of the left ventricle of the heart. A normal EF ranges from 50% to 70%. People with heart failure who have a poor ejection fraction are at risk for fast, irregular and sometimes life-threatening heart rhythms. The CRT/ICD combination device can help protect you against these dangerous, fast heart rhythms.

People with heart failure who have a poor ejection fraction (less than 35%) are at risk for fast, irregular and sometimes life-threatening heart rhythms. CRT may be appropriate for people who:

  • Have severe or moderately severe heart failure symptoms
  • Are taking medications to treat heart failure
  • Have delayed electrical activation of the heart
  • Have a history of cardiac arrest or are at risk for cardiac arrest

Before the procedure begins, a nurse will help you get ready. You will lie on a bed and the nurse will start an IV in a vein in your arm or hand. The IV is used to deliver medications and fluids during the procedure.

To prevent infection and to keep the pacemaker insertion site sterile:

  • An antibiotic will be given through the IV at the beginning of the procedure
  • For men, the left or right side of your chest will be shaved
  • A special soap will be used to cleanse the area
  • Sterile drapes are used to cover you from your neck to your feet
  • A soft strap will be placed across your waist and arms to prevent your hands from touching the sterile area

Yes, a medication will be given through your IV to relax you and make you feel drowsy, but you will not be asleep during the procedure.

The CRT device can be implanted using the endocardial or epicardial approach.

With the endocardial approach (transvenous), a local anesthetic is injected to numb the area, and you will be awake during the procedure. Small incisions are made in the chest where the leads and device are inserted. The leads are inserted through the incision and into a vein, then guided to the heart with the aid of the fluoroscopy machine. Two leads are guided to the right atrium and right ventricle, while the third lead is guided through the coronary sinus to the left ventricle. The lead tips are attached to the heart muscle, while the other ends of the leads are attached to the pulse generator. The generator is placed in a pocket created under the skin in the upper chest. When the endocardial approach is used, the hospital recovery time is generally 24 hours. The endocardial technique is technically challenging. In some cases, this technique may not be successful due to the size, shape, or location of the vein(s). If the endocardial approach cannot be used or is unsuccessful, the epicardial approach will be used.

The epicardial approach may also be used to place the CRT if you are already having surgery to treat another heart condition. With the epicardial (surgical) approach, general anesthesia is given to put you to sleep during the procedure. The leads are guided to the heart with the aid of the fluoroscopy machine. Two leads are guided to the right atrium and right ventricle, while the third lead is guided through the coronary sinus to the left ventricle. The lead tips are attached to the heart muscle, while the other ends of the leads are attached to the pulse generator. The generator is placed in a pocket created under the skin in the lower abdomen. The hospital recovery time is generally 3 to 5 days. Although recovery with the epicardial approach is longer than that of the transvenous approach, minimally invasive techniques enable a shorter hospital stay and quicker recovery time. Your doctor will determine the best implant procedure approach for you, depending on your condition.

After the leads are in place, they are tested to make sure lead placement is correct, the leads are functioning properly and the right and left ventricles are synchronized.

This lead function test is called pacing. Small amounts of energy are delivered through the leads into the heart muscle. This energy causes the heart to contract. You will be asleep for several minutes during the lead function test.

Once the leads have been tested, the doctor will connect them to the device. The rate and settings of your CRT device are determined by your doctor. After the implant procedure, the doctor uses an external device to program final device settings.

With the endocardial approach, you will feel an initial burning or pinching sensation when the doctor injects the local numbing medication. Soon the area will become numb. You may feel a pulling sensation as the doctor makes a pocket in the tissue under your skin for the device. Please tell your doctor what symptoms you are feeling. You should not feel pain. If you do, tell your nurse right away.

With the epicardial (surgical) approach, you will be given anesthesia to put you asleep during the procedure, so you will not feel anything.

With both approaches, you may feel discomfort at the implant site during the first 48 hours after the procedure. The doctor will tell you what what medications you can take for pain relief. Please tell your doctor or nurse if your symptoms are prolonged or severe.

The device implant procedure may last from 2 to 5 hours.

Yes, you will be admitted to the hospital overnight. Usually you will be able to go home the day after your device was implanted, unless the epicardial approach was used during the procedure.

Risks

What are the possible risks of the procedure?

A device implant is generally a very safe procedure. However, as with any invasive procedure, there are risks. Special precautions are taken to decrease your risks. Please discuss your specific concerns about the risks and benefits of the procedure with your doctor.

Before the Procedure

Taking Medication

Usually you will be instructed to stop taking anticoagulant medications, including aspirin or Coumadin, a few days before the procedure. Other blood thinners which need to be stopped include dabigatran, rivaroxaban, apixaban, and edoxaban.

If you take Coumadin, the results of your INR test must be within a suitable range before the implant procedure can be performed.

Your doctor may also ask you to stop taking other medications, such as those that control your heart rate. Do not discontinue any of your medications without first talking to your health care provider. If you have diabetes, ask the nurse how to adjust your diabetes medications or insulin.

Ask your heart doctor which medications you should stop taking and when to stop taking them.

How to Prepare

  • Do not eat, drink, or chew anything after 12 midnight before your procedure. This includes gum, mints, water, etc.
  • If you must take medications, only take them with small sips of water
  • When brushing your teeth, do not swallow any water
  • Remove all makeup and nail polish

What to Bring

  • A family member to wait with you before the procedure
  • Comfortable, easy-to-fold clothing
  • Toiletries and any other items you would like to make your stay more comfortable. Please note, this will be kept with whoever accompanies you
  • A one-day supply of your prescribed medications
  • Do not bring any jewelry, watches, and/or valuables

After the Procedure

What to Expect After the Procedure

In your hospital room, a special monitor (telemetry monitor), will continually monitor your heart rhythm. The telemetry monitor consists of a small box connected by wires to your chest with sticky electrode patches. The box displays your heart rhythm on several monitors in the nursing unit. The nurses will be able to observe your heart rate and rhythm.

You will also have a monitor (small recorder) attached to your chest with sticky electrode patches. The holter monitor records your heart rhythm for 12 hours to ensure that the pacemaker is functioning properly.

A chest X-ray will be done after the device implant to check your lungs and the position of the device and leads. Before you are discharged, the monitor will be removed, and the results will be given to your doctor.

For your safety, a responsible adult must drive you home. Ask your doctor when you may resume driving.

Care For the Insertion Site

You may feel discomfort at the device implant site during the first 48 hours after the procedure. Call your doctor or nurse if your symptoms are prolonged or severe.

Keep the area where the device was implanted clean and dry. Do not scrub the area. Steri-strips may be covering the wound site; they may be removed 3 weeks after the date of the implant. Do not cover the wound unless you have been instructed to do so. You do not need to keep the wound covered with a bandage. Do not use creams, lotions, or ointments on the wound site.

Look at the area daily to make sure it is healing properly. Call your doctor if you notice:

  • Increased drainage, bleeding, or oozing from the insertion site
  • Increased opening of the incision where the device was implanted
  • Redness, swelling, or warmth around the device insertion site
  • Increased body temperature (greater than 101 degrees Fahrenheit)

You may take a shower 5 days after the procedure.

Activities Guideline

For the first week after your procedure:

  • You may move your arms normally and do not have to restrict arm motion during normal activities. However, do not hold your arms above shoulder level for more than several minutes at a time
  • Stop any activity before you become over-tired
  • Try to walk as much as possible for exercise
  • Do not drive for at least one week after your procedure

For the first two weeks after your procedure:

  • Do not lift objects that weigh more than 10 pounds for 2 weeks after the procedure
  • Avoid activities that require pushing or pulling heavy objects
  • Avoid golfing, swimming, tennis, and bowling

Your doctor will tell you when:

  • You can resume driving
  • You can resume more strenuous activities or heavy lifting
  • You can go back to work

Follow Up

A follow-up device check appointment will be scheduled 2-4 weeks after the implant procedure.

This first follow-up appointment is critical. Adjustments will be made that will help your device last longer. An echocardiogram may be performed as part of your first follow-up evaluation.

About the Device

Device Checks

If you have a biventricular pacemaker (cardiac resynchronization therapy device – CRT):

  • After your first follow-up appointment, your pacemaker should be checked every 3 months from home
  • Please make sure that you are set up with a remote monitoring transmitter at the time of your first follow-up for a device check
  • You will receive instructions on how to use remote monitoring during the your first follow-up appointment
  • Your biventricular pacemaker should be checked every 6 months

If you have an implantable cardioverter defibrillator (ICD):

  • After your first follow-up appointment, your device should be checked every 6 months
  • Your device will allow you to use a remote monitoring transmitter. This lets you check your device every night
  • You will receive instructions on how to use remote monitoring during your first follow-up appointment.

Every year, around the anniversary of your device implant, you will have an echocardiogram scheduled along with a complete device check. Since the leads are tested during this appointment, this appointment is different than the telephone transmitter check.

Call your healthcare provider if you have any of these signs of infection:

  • Increased drainage, bleeding, or oozing from the insertion site
  • Increased opening of the incision where the device was implanted
  • Redness, swelling, or warmth around the device insertion site
  • Increased body temperature (greater than 101 degrees Fahrenheit)

The following symptoms may be related to your device:

  • Dizziness
  • Palpitations
  • Fast or slow heart rates
  • Lose or nearly lose consciousness before receiving therapy from the device
  • Have numbness or tingling of the arm closest to the device

If you have a telephone transmitter please call the transmitter line 8 a.m. – 5 p.m., Monday through Friday to check your device.

If you have a remote monitor please call the clinic between the hours of 8 a.m. – 5 p.m., Monday through Friday and we will instruct you to sent us a transmission.

Device Therapy

If you receive therapy from your ICD device:

  • Stay calm or lie down
  • If someone is touching you when the device delivers therapy or fires, he or she may feel a tingling sensation; this is not harmful
  • If possible, ask someone to stay with you until you feel better
  • If you feel fine after the shock, you do not need to seek medical attention
  • Call your doctor within 24 hours.

Call your doctor if you:

  • Do not feel well within 5 to 10 minutes after receiving the shock; call your doctor or 9-1-1
  • Received a shock, this needs to be done within 24 hours of the shock
  • Received therapy from the device two or more times in a 48 hour period
  • Received therapy from the device before your 6-8 week follow-up visit

What Therapy From Your Device Will Feel Like

You may or may not be able to tell when your device detects and corrects your heart rhythm. It often depends on the type of therapy you receive from the device:

  • Pacing: You may or may not feel the impulses. They are usually painless
  • Cardioversion: The shock may feel like a thump on the chest, but it only lasts for a moment
  • Defibrillation: The shock may feel like a kick in the chest, but it only lasts for a moment. Some patients describe the feeling as a shock from an electrical outlet.

Most of the time, you will be awake for the therapy, but you may lose consciousness prior to the shock.

What to Do With Your Device If You Need Surgery

Your cardiologist will tell you if programming changes are needed before or after your surgery.

Your pacemaker should be checked within 3 months before your surgery; please schedule an appointment with your cardiologist.

If you have an ICD, the shock therapies will need to be programmed off during surgery. Please contact your doctor’s office so they can make arrangements for this.

How Long Your Device Will Last

ICDs and CRT devices last 6 to 8 years.

Living With the Device

Most household appliances do not interfere with pacemakers

Cell Phones

While your cell phone may not affect your pacemaker, to be safe, use your cell phone on the side opposite of where the device was implanted. Cell phones should not be placed directly against the chest or on the same side as your device.

Headphones

Certain types of headphones may contain a magnetic part that can affect pacemaker function. Keep headphones 1-2 inches away from your pacemaker. Do not keep your headphones in the breast pocket of a shirt or drape them around your neck.

Security Devices

If you must pass through entrances where anti-theft devices or metal detectors are being used for security, be sure to walk quickly through them. If hand-held metal detector scanning is necessary, tell the security personnel that you have a pacemaker. You should not hold the metal detector near the device for any length of time.

Powerful Magnets, Magnetic Fields, and Equipment

You will need to avoid strong electric or magnetic fields, such as:

  • Some industrial equipment
  • Ham radios
  • High intensity radiowaves
  • Arc resistance welders.

In strong magnetic fields, the device stops monitoring your heart rhythm. Once you are out of these fields, normal device function resumes and there is no damage to the device.

Magnetic Resonance Imaging (MRI)

Some devices are compatible with MRIs. If you have been instructed to have an MRI, contact your implanting physician about the type of device that you have implanted and if this type of testing is safe for you.

Hybrid Cars

Stay about 2 feet away from the engine and do not keep your smart key near your device. Do not put it in a pocket that is over your device.

We know these are very conservative recommendations and there have been no reports of adverse outcomes due to exposure to either of these environments. However, this information has been recommended by current sources and is the best information we have at this time.

If you have any questions about the use of equipment around your device, check your device manufacturer website and ask your doctor or nurse.

Electric Fence For Pets

Stay at least a foot away.

We know these are very conservative recommendations and there have been no reports of adverse outcomes due to exposure to either of these environments. However, this information has been recommended by current sources and is the best information we have at this time.

If you have any questions about the use of equipment around your device, check your device manufacturer website and ask your doctor or nurse.

Carry an ID Card

You will receive a temporary ID card that tells you what type of device and leads you have, the device manufacturer, the date of the device implant, and the name of the doctor who implanted the pacemaker.

Within three months you will receive a permanent ID card from the device company. It is important to carry this card at all times in case you need medical attention or to tell people you have a pacemaker.

Let your healthcare providers know you have an implanted device. In rare occasions they may want to adjust your treatment plan because you have a pacemaker or defibrillator.

Airport Security

For patients who travel outside of Houston, our cardiology specialists recommend taking a few precautions. Should the security personnel use a wand to clear people, show them your card, and ask them to avoid placing the wand over your implanted heart device. Ask security if there is another method for clearance.