World’s smallest pacemaker is activated by light

Northwestern University engineers have developed a pacemaker so tiny that it can fit inside the tip of a syringe — and be non-invasively injected into the body.

Although it can work with hearts of all sizes, the pacemaker is particularly well-suited to the tiny, fragile hearts of newborn babies with congenital heart defects.

Smaller than a single grain of rice, the pacemaker is paired with a small, soft, flexible, wireless, wearable device that mounts onto a patient’s chest to control pacing. When the wearable device detects an irregular heartbeat, it automatically shines a light pulse to activate the pacemaker. These short pulses— which penetrate through the patient’s skin, breastbone and muscles — control the pacing.