Implantation of pacemakers

The most common condition requiring a pacemaker is bradycardia; a heart rate that is too slow for the body’s demands. Symptoms of bradycardia may include dizziness, extreme fatigue, and shortness of breath or fainting spells. Bradycardia is most commonly caused by ‘sick sinus syndrome’ (when the sinus node sends out electrical impulses too slowly or irregularly) or ‘heart block’ (when the electrical impulse is slowed, becomes irregular or is stopped).

A pacemaker restores regular electrical impulses to your heart. The pacemaker has two basic parts - a pulse generator (which contains the battery and circuitry and functions like a miniature computer by controlling the timing of electrical impulses sent to the heart) and pacing leads (which are insulated wires the electrical impulses travel through). At the tip of the lead is a metal electrode that the pacemaker uses to monitor the heart’s electrical activity. It is able to send out electrical impulses when the heart needs them.

Pacemakers have a special sensor that detects changes in your exercise state. The pacemaker’s circuitry interprets these changes and increases or decreases the pacing rate to meet your body’s demands. It will increase with physical activity (i.e. walking, gardening or exercising) and will slow down accordingly with rest or sleep.

The type of pacemaker you require will depend upon your medical condition. You may require a single chamber, dual chamber or bi-ventricular pacemaker.

In many heart rhythm disturbances, your heart may beat normally part of the time and therefore your pacemaker will only work when required. The pacemaker stores information about your heart’s rhythm. It is completely programmable and if your pacing requirements change this is easily attended to in your Doctor’s rooms without the need for any further hospitalisation.

The pacemaker is implanted transvenously. The leads are introduced into a vein in the left upper chest region. The lead is then threaded through the vein to the appropriate chamber in the heart. The procedure is performed in the Cardiovascular Theatre and requires only a local anaesthetic.