Cardiac Resynchronization Therapy Procedure

Overview

Doctors may suggest cardiac resynchronization therapy (CRT) for people with moderate to severe heart failure who have not improved enough with medicines. CRT can be especially helpful for those who have irregular electrical signals in their heart, like left bundle branch block (LBBB), or for people who experience heart rhythm problems such as arrhythmias. Some common reasons why a patient might need CRT include:

Having heart failure with symptoms such as shortness of breath, fatigue, or trouble exercising.
Needing a pacemaker or implantable defibrillator due to serious heart rhythm issues.
Having a low left ventricular ejection fraction (LVEF), which means the heart is not pumping enough blood.
Showing wide QRS duration on an electrocardiogram (ECG), a sign of electrical dyssynchrony.
Belonging to New York Heart Association (NYHA) class II, III, or sometimes IV heart failure.

When patients receive CRT for these conditions, the therapy improves the coordination of the heart chambers (ventricular contraction). This helps the heart pump blood better to the body, which can improve daily activities and quality of life. Benefits of CRT include:

Benefit	How It Helps the Patient
Better blood flow	Improves heart pumping to organs and tissues.
Fewer hospital stays for heart failure	Reduces need for emergency care.
Fewer symptoms (less fatigue, more energy)	Improves breathing and essens tiredness.
Potential lower risk of sudden cardiac death	Especially with CRT-D devices.
Lower risk for heart remodeling	Helps prevent worsening of heart structure.

CRT may be part of a broader treatment plan that includes medications, lifestyle changes, and regular follow-up appointments. Doctors typically do not use CRT for people who have only mild symptoms of heart failure.

Step-by-Step Surgical Procedure

Before the Procedure

Medical staff insert an intravenous (IV) line in the patient’s arm or hand.
The team gives a sedative to help with relaxation.
The doctor administers local anesthesia to numb the area of the chest where the CRT device will go, so the patient remains comfortable but awake or only lightly sedated.

During the Procedure

The doctor usually completes the surgery in a few hours.
The doctor makes a small cut near the collarbone.
The doctor threads wires called leads through a vein into the heart, using X-ray images for guidance:
- One lead to the right ventricle
- One to the right atrium (sometimes)
- One to the left ventricle (placed via the coronary sinus)
The doctor connects the leads to a CRT device (usually a pacemaker or a combined pacemaker-defibrillator) that sits under the skin.
The team programs the device to send electrical signals, helping the ventricles contract at the same time. Some CRT devices (CRT-D) also monitor the heart rhythm and deliver a shock if they detect a dangerous rhythm.

After the Procedure

Most patients stay in the hospital overnight while the team monitors them through electrocardiograms and other checks to ensure the device works.
Care instructions include:
- Limiting arm and upper body movement for several weeks
- Avoiding heavy lifting or strenuous activity for about a month
- Attending follow-up care visits to check device function and adjust programming if needed
Patients can usually return to normal activities within a few days, but should have someone else drive them home from the hospital.

CRT devices (CRT-P or CRT-D) are usually safe around everyday electronics, but patients should talk with the healthcare team about any special precautions. CRT-P is a pacemaker only, while CRT-D combines a pacemaker with a defibrillator that can correct life-threatening heart rhythms. The choice depends on a patient’s condition and risk factors.

Possible Complications and Side Effects

While CRT can be very helpful, the procedure and the device can come with risks and possible side effects. The chances of these problems can depend on the patient’s health, age, and the type of CRT device used. Possible risks include:

Infection: Infection can develop at the site where the device is placed.
Bleeding: Patients may bleed during or soon after the surgery.
Collapsed Lung (Pneumothorax): Placing the leads near the lungs can occasionally cause a collapsed lung.
Fluid Buildup or Bleeding Around the Heart: If the procedure causes a hole in the heart, fluid or blood may collect around it.
Device Issues: The pacemaker or defibrillator may not work correctly, or its wires (leads) can move out of place, sometimes requiring another operation.
Blood Clots: Blood clots can rarely form around the leads or in veins.

Other less common concerns include unfavorable reactions to anesthesia, ongoing pain, bruising, or swelling near the device site. Doctors and nurses lower these risks by using sterile techniques, planning the procedure carefully, and using X-ray imaging to place CRT leads properly into the heart through the venous system, such as the coronary sinus for left ventricular lead placement.

Results and Long-Term Outcomes

Cardiac resynchronization therapy (CRT) often improves both symptoms and quality of life in patients with heart failure. Many people feel more energetic, breathe more easily, and find it easier to stay active after the device is placed. Some patients notice improvement within a few weeks, while for others, benefits develop gradually over several months. In the long term, CRT can:

Reduce hospitalizations for heart failure.
Lower the risk of death from heart-related causes, especially when using CRT-D (with defibrillator).
Improve heart function, including higher ejection fraction in some patients.
Slow or reverse heart remodeling, reducing strain on the heart walls.
Support longer survival, especially when combined with other treatments.

CRT does not work for everyone. Doctors usually follow up with regular tests such as echocardiograms and device checks to monitor progress. If CRT is not effective, the care team may adjust the device settings or explore other therapies. Long-term success with CRT also depends on healthy lifestyle habits.

Patients should take medications as prescribed, avoid tobacco, follow dietary recommendations, and attend regular checkups to monitor heart function and device settings. Cardiac rehabilitation programs may also improve strength and stamina. Patients who respond well to CRT are often called “responders.” Predicting who will respond best is still an area of medical research.

Even if results vary, CRT remains an important option for managing moderate to severe heart failure. Adjusting to a heart device can bring emotional changes, especially at first. Some patients may feel anxious or self-conscious about having an implant. Support groups, counseling, or talking openly with healthcare providers can help ease this transition.