Back in Ancient Rome, physicians used to treat heart problems with electric rays. But it wasn’t until the late 19th century that doctors and scientists finally realized the heart worked with currents and could be revived with electricity.
Fast-forward 50 years, to 1928, where an Australian anesthesiologist developed the first external instrument that would deliver currents via needles implanted directly into the heart. Ouch.
Picking up the pace
Meanwhile, in 1932 in the United States, a physiologist was hard at work creating what he dubbed the first artificial pacemaker. This device used bipolar needles inserted into the heart, but the current was delivered by winding the device manually.
Twenty years later, the artificial pacemaker was designed to be more portable. However, it still needed to be plugged into an electric outlet, making the host only as portable as an extension cord. A few years later, a revised model used batteries instead of outlets, but these only lasted 1,000 hours.
It wasn’t until the mid-1960s that implantable pacemakers no longer required anesthesia or thoracotomies, working as-needed instead of continuously. To help extend the pacemaker’s life, lithium-iodine batteries were created to replace their mercury-oxide-zinc predecessors.
The 1980s brought with them the redesign of the leads to emit steroids as a means of decreasing the tissue swelling around the implants. The advances also allowed for dual-chamber pacing — contraction of both the atria and ventricles of the heart. And in the 1990s, microprocessors were used to adapt and meet the changing needs of the patient’s heart.
With the technology boom of the 21st century, implantables became able to record and upload the heart’s data via Wi-Fi. These life-saving devices are now also able to defibrillate the heart by restoring it back to normal function.
The modern pacemaker weighs less than an ounce. More recent models can respond to changes in blood temperature and breathing. They can also self-adjust based on the person’s activities.
What’s next? The future of pacemakers is limitless. Modern-day batteries could mean a longer life. Improved leads could reduce the body’s chance of rejection. Pacemakers could even become the size of dimes.