One in eighteen people in the United States have an arrhythmia (an irregular heartbeat). For adults over forty, one in four could develop an arrhythmia. An irregular heartbeat could last for a brief amount of time and be harmless to a person's health. On the flip side, arrhythmias that persist for a long period of time can increase stroke risk and lead to premature death. Possible treatment options include open heart surgery but more commonly default to pacemaker placement. In fact, almost three million Americans live with pacemakers. However, a new treatment option designed by Northwestern University and the University of Texas at Austin offers a sophisticated alternative to pacemakers.

Similar to a child's temporary tattoo, a new graphene "tattoo" implant has been developed to treat arrhythmias. The implant is similar to a pacemaker in function but differs in its composition and structure. Pacemakers utilize hard, rigid materials that are incompatible with the body. The new device softly melds to the heart the way a temporary tattoo melds to skin. The implant is thinner than a strand of hair, allowing it to conform to the heart's shape. The material is also flexible, allowing the heart to beat freely without constraint.

The implant was tested in rats and successfully sensed irregular heart rhythms. Using this information, the implant delivers electrical stimulation through a series of pulses to set a regular pace for the heart. It does so without constraining or altering the heart's typical motion. Additionally, the material is transparent, allowing researchers to use an external source of light to record and stimulate the heart during testing.

Typical pacemakers are difficult to affix to the surface of the heart. They often utilize coils and wires that are made of thick, inflexible cords. This can cause damage to both the pacemaker and the heart. Scientists have observed that when rigid interfaces meet soft tissue, they are often incompatible and restrict motion. Alternatively, the new implant is soft and flexible and conforms to the heat directly. This means that it will conform to each heart differently, offering a more personalized treatment for arrhythmias.

Graphene tattoos had previously been developed for skin to monitor vitals and blood pressure. However, the material had to be reimagined for use on the heart. First, the graphene was encapsulated in silicon for increased flexibility. Additionally, gold tape was used as a conductor between the graphene and the heart. In total, the implant measures to be 100 microns thick, which is close to the thickness of a strand of hair. The device is stable for around 60 days, similar to a traditional pacemaker's lifetime.

The implant offers an efficient treatment option for arrhythmias. On top of that, the material is flexible, allowing it to mold to each person's heart in a different way. The implant requires further testing in humans, but its success so far suggests that we are entering a new stage in heart treatment options. The material could also show promise in treating other organs within the body.