Pacemakers have been around for decades but advancements in technology mean this lifesaving device keeps getting smaller, smarter and more efficient. So how do they work?
A pacemaker is the most common way to treat slow heart rates, or bradycardia. This often happens quite naturally as people age but may also be caused by heart block, where damaged nerves prevent signals from travelling through the heart.
Unlike defibrillators, which treat life-threatening rapid heart rhythms, pacemakers are often for people with normal hearts but a slow heart rate, usually less than 50-60 beats per minute. A rate this low makes it difficult for the heart to pump enough blood to the body, so patients experience symptoms such as light-headedness, shortness of breath, lack of energy and fainting spells.
The pacemaker itself is a tiny device, weighing only around 30 grams, that’s attached to one, two or sometimes three leads (wires). It’s fitted under the skin near the collarbone, reaching the heart through a vein in the shoulder.
A computer inside the pacemaker analyses heart rhythm and, if it slows down, sends an impulse to restore it to an appropriate rate. It can also record heart rhythms which can be downloaded for analysis.
“By and large patients can swim, travel, play golf, drive, basically do everything they used to do, two – four weeks after implantation,” says cardiologist, Dr Andrei Catanchin.
“These devices aren’t designed to restrict life, they’re design to enable people to do what they like to do, with a safe heart rate.”
Research to improve the technology is ongoing. The latest development is a tiny leadless pacemaker, smaller than a AAA battery, that can be implanted via a vein the leg and attached to the heart.
“It’s the way of the future,” says Dr Catanchin. “Minimal hardware, no cutting and nothing outside the heart. These sophisticated new devices are just starting to be implanted in Australia and we hope to do our first at Epworth very soon.”
Did you know?
- These days, fitting a pacemaker is a routine, minor procedure that can be performed under local anaesthetic. It’s actually one of the gentler, lower-risk procedures performed by cardiologists.
- For some time now doctors have been able to monitor pacemakers remotely. A device in the patient’s home communicates with the pacemaker and his or her medical team. This not only saves travel time, especially helpful for regional patients, it also works as an early alert system if something is going wrong.
- Pacemakers are now MRI (Magnetic Resonance Imaging) safe. In the past sending a patient with a pacemaker for an MRI would have presented a significant health risk.
- Pacemakers are so sophisticated they can sense movement, speeding up the heart when patients exercise and slowing it down when they’re resting.
- Battery technology has improved so significantly over recent years that pacemaker batteries now last at least 10, sometimes up to 13 years.