Cardiac Pacing for Irregular Heartbeat
Information on Pacemaker Types, Placement Procedure, Cautions
Aug 22, 2009
A cardiac pacemaker is an external or implanted device used to treat an irregular heartbeat. In a healthy heart, the beat is controlled by electrical impulses from a region called the sinus node. Heart problems that disrupt this electrical activity can cause the heart to beat too slowly (bradycardia), too quickly (tachycardia) or with an abnormal pattern (e.g. atrial fibrillation). The collective term for such disorders is ‘cardiac arrhythmia’.
Types of Pacemaker
Cardiac pacemakers can be temporary or permanent.
Temporary pacemakers are generally used in emergencies, to control the heartbeat until a permanent pacemaker can be fitted. For temporary pacing, adhesive pads containing electrodes are placed on the skin of the patient’s chest. Alternatively, a wire connected to an external pacemaker is inserted into the heart through a vein, under a local anaesthetic.
Permanent pacemakers are internal devices implanted into the chest. A modern pacemaker is smaller than a matchbox, weighs only 20–50 grams (British Heart Foundation) and consists of:
- a pulse generator, to produce electrical signals
- a sensor, to monitor the heartbeat
- electronic circuits, to control the pacemaker
- a lithium battery
- one or more electrode leads.
The pulse generator, sensor, circuits and battery are sealed within a case made from titanium, an unreactive metal that is rarely rejected by the body’s immune system. The electrode leads extend from the pacemaker into the heart.
Permanent Pacemaker Placement Procedure
Cardiac pacemakers are usually placed under the layer of skin and fat just beneath the left collar bone. In most cases, the surgery is performed under a local anaesthetic with a sedative to relax the patient, though a general anaesthetic may be used instead. After implanting the pacemaker through a small incision, the surgeon passes the electrode lead or leads into the heart through a suitable large vein.
Following the procedure, the pacemaker is tested to find the best settings for the individual patient’s arrhythmia. Settings can be adjusted and information about the working of the pacemaker obtained via a device called a 'programmer', which can communicate wirelessly with the pacemaker.
The patient is usually able to return to his or her everyday activities after about a week.
How a Pacemaker Regulates Heartbeat
A cardiac pacemaker takes over the function of the heart’s natural pacemaker, the sinus node. By sending electrical signals into the muscles of the heart at the correct frequency, it causes the heart to beat at a normal rate, overcoming the arrhythmia.
People with a permanent pacemaker need regular check-ups to ensure that the device is working properly. Pacemaker batteries have a life of about ten years or so; after this time, the old pacemaker is removed and a new one inserted in its place. This is a simpler procedure than the original implantation, however, as the leads are usually left in place and reconnected to the new pacemaker.
Pacemaker Cautions
Pacemakers are generally safe and trouble-free in use, but care should be taken in certain situations.
- People with a pacemaker should avoid playing contact sports such as rugby and boxing, where the pacemaker or its leads might become damaged.
- Strong magnetic fields – such as those inside an MRI scanner – can interfere with pacemaker activity. It is important to inform hospital staff about the presence of a pacemaker before undergoing any kind of scan or surgery.
- When travelling, pacemaker-users should tell airport security staff about their device before passing through the security system. The check should be performed by hand or using a hand-held metal detector, ensuring that the detector is not placed directly over the pacemaker. International Pacemaker Patient Identification Cards are available, and can be helpful in such circumstances.
A doctor or pacemaker clinic will be able to advise on other potential problems that might be encountered in everyday life.
Living With a Cardiac Pacemaker
Modern permanent pacemakers such as the Guidant and the St Jude Medical Pacesetter are unobtrusive in use and reliable in action. With proper care and regular check-ups, they can greatly improve the quality of life – or even save the life – of people with heart disease.
Reference
British Heart Foundation. Pacemakers. Accessed 22-08-09
Disclaimer
The information contained in this article is for educational purposes only and should not be used for diagnosis or to guide treatment without the opinion of a health professional. Any reader who is concerned about his or her health should contact a doctor for advice.
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