Biventricular pacing devices are used in people whose heart failure has caused the ventricles to beat "out of synch" instead of in a coordinated way.
In biventricular pacing, implanted devices send electrical signals to the main chambers of the heart, which restore synchronization.
The devices can pace the heart only, or can include a defibrillator, which can protect against sudden cardiac death.
Restoring ventricular synchronization has been shown to improve symptoms and quality of life in recipients and reduces the chances of dying. The procedure typically requires an overnight hospital stay and rarely causes complications.
In biventricular pacing, physicians implant devices in patients who have moderate to severe heart failure, which has caused the ventricles, which normally contract simultaneously, to beat at different times (dysynchrony or asynchrony). Dysynchrony can further weaken the heart in patients who experience it. Physicians can implant a device to restore the synchronization, called cardiac resynchronization therapy (CRT). These CRT devices can pace the left and right ventricles, thus resynchronizing the heartbeat. In addition, many of these devices can also provide a small electrical shock to the heart to restore a normal rhythm and prevent sudden cardiac death.
WHEN IS IT INDICATED?
Biventricular pacing is indicated for people who have:
Moderate to severe heart failure symptoms despite lifestyle changes and optimal medication;
A weakened and enlarged heart; and
Left bundle branch block.
The physician may order an electrocardiogram or an echocardiogram before the implantation procedure. On the day of the procedure, the person needs little preparation other than to communicate how he or she is feeling. The patient should inform the physician about all medications taken within the past month (including vitamins and supplements), and in most cases avoid eating 12 hours prior to the surgery.
WHO IS ELIGIBLE?
Patients who have moderate to severe heart failure symptoms despite lifestyle changes and optimal medical therapy and ventricular dysynchrony are eligible for cardiac resynchronization therapy.
RISK FACTORS FOR POSSIBLE COMPLICATIONS
The following factors can interfere with the effectiveness of a CRT device:
Abnormal electrolyte levels; and
WHAT TO EXPECT
CRT device insertion can be done on an inpatient or an outpatient basis, typically in an electrophysiology laboratory. The insertion point is cleaned and shaved to minimize infection risk, as well as receive an anesthetic to numb the area. The physician then makes a small incision in the chest wall, just below the clavicle (collarbone). Next, the physician creates a small pocket in the chest wall just below the clavicle and places the device into the pocket. The device leads are then passed through a vein in the upper chest and directed to the right atrium and the left and right ventricles, using fluoroscopy for guidance. The physician attaches one lead to the inner right atrium, the second lead to the inner right ventricle, and the third lead to the left ventricle by way of the coronary sinus. Small screws or tines attach the leads to the heart. Following insertion, the skin is closed with sutures or staples.
The procedure typically takes approximately 2 hours.
An overnight hospital stay is typically required to confirm that the patient's condition is stable. The physician may order an x ray, ECG, or echocardiogram to ensure the device and leads are in the proper location and working correctly. Ten to 14 days after surgery, the sutures or staples will be removed.
Complications are rare, but may include:
Severe bruising or bleeding;
Formation of blood clots;
Tearing of a blood vessel;
Puncturing of the lung or heart muscle;
Introduction of air into the space between the lung and chest wall, which could collapse a lung;
A lead wire dislodging from the heart;
Device malfunction; and
Infection of the pocket into which the device was placed.