Get back your beat

Posted on 12 July 2013

When your heart skips a beat, a simple electronic device can get it back in sync. Discover how a pacemaker can change your life – in a heartbeat.

Words Linda Pretorius

Beat box
An electronic pacemaker is a small implantable device, about the size of a matchbox but only half as thick, that can restore your natural heartbeat. It consists of a small steel casing that houses a tiny electronic circuit and battery to generate a pulse, connected to flexible conducting wires called leads. ‘Pacemakers have varied degrees of sophistication,’ says Dr Zaid Mohamed, a cardiologist at Mediclinic Constantiaberg. ‘With a single-chamber system, a single lead carries the electrical signal from the generator to stimulate either the right atrium or the right ventricle. A system with two leads is used if your heart beats only intermittently by itself and the connection between the right atrium and ventricle is interrupted. Sometimes the heartbeat is so out of sync that a biventricular system, with leads to the right atrium and both ventricles, is needed to restore a natural heart rhythm,’ he explains.

Most pacemakers nowadays also include a sensor that monitors your heartbeat and pulse only when no natural beat is detected. This helps to ensure efficient energy use so that the battery life can be prolonged. On average, a pacemaker battery needs to be replaced after eight to 10 years. The pacemaker records information about the pattern of your heartbeat and battery efficiency so that your doctor can assess the device function during your checkups.

How a pacemaker is inserted
Step 1 An incision of about 5 cm is made in the muscle under your collarbone. (The pacemaker is usually implanted on the side opposite your dominant arm.)
Step 2 The leads are threaded through the subclavian vein into the heart chambers, with the progress of their journey monitored continuously on a video screen.
Step 3 Once in the correct position, the free ends of the leads are connected to a portable device to test proper conduction and determine the optimal pulse settings. The leads are then connected to your pacemaker’s pulse generator.
Step 4 The box is inserted in the pocket prepared in the chest muscle, and the incision is stitched closed.

Your heart is like your body’s metronome, beating regularly 60 to 100 times every minute. This is thanks to an elegant conduction system that allows self-generated electrical pulses to spread across the heart muscle in an orchestrated way, stimulating first the two upper heart chambers (atria) to expand and then the two lower ones (ventricles) to contract.

The circuit in short
There are three main relay stations along this conduction path. The sinoatrial node, a cluster of cells in the right atrium, gets the ball rolling, discharging at a fixed rate. The pulse then reaches another cluster of cells at the border between the right atrium and ventricle, called the atrioventricular node. From here the signal flows along bundles of conducting fibres to the right and left ventricles. ‘Damage or malfunction at any station along this conduction system will disrupt the circuit, causing an abnormal heartbeat, and so prevent efficient blood supply to the rest of the body,’ explains Dr Mohamed.

‘I’ve been given a new lease on life’
‘About a year and a half ago, I started feeling dizzy whenever I stood up and could hardly walk without support. After tests had ruled out any underlying neurological cause for my dizziness, I was referred to a cardiologist,’ says Dawn Lackay (72). ‘After the examination, the doctor told me, “You need a pacemaker to help your heart pump enough blood to your body,”’ she recalls. Dawn had a dual-chamber pacemaker implanted a few weeks later. ‘The operation was done under local anaesthesia and I was awake the whole time. I could feel how the doctors worked, but I experienced no pain; it felt almost as if someone was kneading my chest lightly. The staff were very considerate of my needs and talked to me throughout the procedure.’

Feel the rhythm
To monitor your heartbeat, place the tips of your second and third fingers of one hand on the opposite wrist, just below the base of your thumb. Press down gently until you feel a pulse and count the beat for one minute. It’s best to monitor your heart rate once you’ve been sitting relaxed for about 10 minutes.

The pace of life
‘A pacemaker gives back life. It’s one of the most beautiful gifts you can give a patient,’ says Dr Melt van der Spuy, a cardiologist at the Mediclinic Heart Hospital in Pretoria. Dizziness, shortness of breath and a chronic lack of energy are telltale signs that something could be amiss with your heart. Your doctor will conduct a range of tests, including blood and urine analyses, an ECG and X-rays, to confirm that your abnormal heartbeat is caused by faulty electrical conduction before suggesting a pacemaker best suited to you.

Most pacemaker patients are older people, but young people and even children with a congenital conduction disorder may have a pacemaker implanted. ‘On average, the procedure takes about an hour and can be done under either local or general anaesthesia, whatever makes for the most comfortable procedure. After the operation, you will have to stay in hospital for observation for about a day and then have a follow-up visit a month later to check that everything works as it should. Routine checkups are then required every six months,’ explains Dr van der Spuy.

Living with a pacemaker
‘You can lead a normal, active life with a pacemaker,’ says Dr Zaid Mohamed, a cardiologist at Mediclinic Constantiaberg. Here are a few things to keep in mind:
You won’t be able to see the pacemaker, because it is hidden under the skin in your chest. The only clue may be slight scarring where the incision was made.
A pacemaker will activate metal detectors, but passing through a detector won’t reset the programmed settings of the pacemaker. Carry some identification showing that you have a pacemaker to avoid unnecessary inconvenience at airports, shops and banks.
X-rays and CT scans are safe when you have a pacemaker, but you won’t be able to have an MRI scan because of the strong magnetic field. Always tell medical staff that you have a pacemaker before any medical procedure is performed.
You can still exercise and participate in normal physical activity when you have a pacemaker. The arm on the side opposite the implant should be used when you play golf, tennis or squash. Contact sports like boxing and rugby, however, are out.

The information provided in this article was correct at the time of publishing. At Mediclinic we endeavour to provide our patients and readers with accurate and reliable information, which is why we continually review and update our content. However, due to the dynamic nature of clinical information and medicine, some information may from time to time become outdated prior to revision.