Condition for Pacemaker Implantation
A pacemaker insertion is the implantation of a small electronic medical device that sends out small electrical impulses to make the heart beat in a regular rhythm and at a normal speed. It is usually placed in the chest (just below the collarbone)
Purpose Of A Pacemaker -The primary purpose of a pacemaker is to maintain an adequate heart rate, either because the heart's natural pacemaker is not fast enough, or because there is a block in the heart's electrical conduction system.
Diagnosis Before Pacemaker Implantation :
- Holter Monitoring
- Stress Test
Percussive pacing : Percussive pacing, , is the use of the closed fist, usually on the left lower edge of the sternum over the right ventricle in the vena cava, striking from a distance of 20 – 30 cm to induce a ventricular beat .This is an old procedure used only as a life saving means until an electrical pacemaker is brought to the patient.
Transcutaneous Pacing : Transcutaneous pacing (TCP), also called external pacing, is recommended for the initial stabilization of hemodynamically significant bradycardias of all types. The procedure is performed by placing two pacing pads on the patient's chest, either in the anterior/lateral position or the anterior/posterior position. The rescuer selects the pacing rate, and gradually increases the pacing current until electrical capture is achieved, with a corresponding pulse. It is an emergency procedure that acts as a bridge until transvenous pacing or other therapies can be applied.
Epicardial Pacing : Temporary epicardial pacing is used during open heart surgery .The electrodes are placed in contact with the outer wall of the ventricle (epicardium) to maintain satisfactory cardiac output until a temporary transvenous electrode has been inserted.
Transvenous Pacing (temporary) : Transvenous pacing, when used for temporary pacing, is an alternative to transcutaneous pacing. A pacemaker wire is placed into a vein, under sterile conditions, and then passed into either the right atrium or right ventricle. The pacing wire is then connected to an external pacemaker outside the body. Transvenous pacing is often used as a bridge to permanent pacemaker placement. It can be kept in place until a permanent pacemaker is implanted or until there is no longer a need for a pacemaker and then it is removed.
Subclavicular Pacing : The procedure is performed by incision of a suitable vein into which the electrode lead is inserted and passed along the vein, through the valve of the heart, until positioned in the chamber. The procedure is facilitated by fluoroscopy which enables the physician to view the passage of the electrode lead. After satisfactory lodgement of the electrode is confirmed, the opposite end of the electrode lead is connected to the pacemaker generator.
There are three basic types of permanent pacemakers, classified according to the number of chambers involved and their basic operating mechanism:
Single-chamber pacemaker. In this type, only one pacing lead is placed into a chamber of the heart, either the atrium or the ventricle.
Dual-chamber pacemaker. Here, wires are placed in two chambers of the heart. One lead paces the atrium and one paces the ventricle. This type more closely resembles the natural pacing of the heart by assisting the heart in coordinating the function between the atria and ventricles.
Rate-responsive pacemaker. This pacemaker has sensors that detect changes in the patient's physical activity and automatically adjust the pacing rate to fulfill the body's metabolic needs.
To achieve Cardiac resynchronization therapy (CRT), a biventricular pacemaker (BVP) is used, which can pace both the septal and lateral walls of the left ventricle. By pacing both sides of the left ventricle, the pacemaker can resynchronize the ventricular contractions.
Procedure of Implantation
The procedure is performed using analgesics and sedatives and with antibiotic cover. The area of the implantation may be shaved and cleaned prior to implantation as necessary to reduce the chance of infection.
During the procedure an ECG and blood pressure monitor will allow your heart rate and blood pressure to be recorded while you lie on the table in the cardiac catheter laboratory. In addition to the conscious sedation, local anaesthetic will be injected under the skin in the area of the pacemaker insertion. A 5-10cm incision will then be made below the collar bone and a small pocket under the skin or muscle will be made for the pacemaker battery, and one or more leads will be inserted into a nearby vein so they can be passed to the heart using x-ray control. The cardiologist will then close the incision with sutures and apply a dressing to the skin over the wound.
Recent Advances –
Implantable cardioverter defibrillators (ICDs)
An implantable cardioverter defibrillator (ICD) is a device similar to a pacemaker. It sends a larger electrical shock to the heart that essentially "reboots" it to get it pumping again. Some devices contain both a pacemaker and an ICD.
ICDs are often used as a preventative treatment for people thought to be at risk of cardiac arrest at some point in the future. If the ICD senses the heart is beating at a potentially dangerous abnormal rate, it will deliver an electrical shock to the heart. This often helps return the heart to a normal rhythm.
A conventional ICD has a pacing lead that's implanted along a vein (transvenously). There's also a newer type of ICD where the pacing lead is implanted under the skin (subcutaneously).
'Dynamic Pacemaker', could compensate for both actual respiratory loading and potentially anticipated respiratory loading. Dynamic pacemaking technology could also be applied to future artificial hearts. Advances in transitional tissue welding would support this and other artificial organ/joint/tissue replacement efforts. Stem cells may or may not be of interest to transitional tissue welding.
Many advancements have been made to improve the control of the pacemaker once implanted. Many of these have been made possible by the transition to microprocessor controlled pacemakers. Pacemakers that control not only the ventricles but the atria as well have become common. Pacemakers that control both the atria and ventricles are called dual-chamber pacemakers.
Nanostim Leadless Pacemaker - One of the most innovative technologies discussed at the meeting was the Nanostim leadless pacemaker, Singh explained. The tiny device, about the size of the tip of a pen, is implanted via catheter inside the heart. It attaches to the wall of the left ventricular apex with a screw-in active fixation mechanism. The small size of the device — less than 10 percent the size of a conventional pacemaker — allows for percutaneous placement through an 18 French sheath in the femoral vein, using a steerable catheter.
Success Rate –
For a 3-lead pacemaker system, the success rates are about 97 percent. The risks of major complications from a pacemaker implant are low.
Hospital Stay –
It takes 1-2 hours for the complete procedure. New pacemaker implants require one nights stay in hospital.