The new device is designed as a small sticker that can be worn on the chest. Tiny transducers on the sticker send ultrasound pulses through the chest to stimulate the heart. The ultrasound waves trigger the opening of certain ion channels in heart cells, an effect the researchers amplified through genetic engineering. When the channels open, they let in calcium, which signals a heart cell to squeeze and beat.

In experiments in the lab, the researchers applied ultrasound waves to engineered human cardiac cells and found that the pulses effectively maintained the cells’ healthy contractions. They also tested the ultrasound sticker on rats and found the device quickly, safely, and noninvasively corrected arrhythmias and restored normal, regular heart contractions.