How an Electromechanical Hug Could Prevent Heart Attacks

Korean researchers make a wire wrap to stop rapid heart beat and restore cardiac electrical function.

Nancy Crotti

Cardiac pacemakers keep getting smaller, and now come in wireless varieties, but they still have a problem--they only reach part of the heart.

Researchers in Korea have devised a shape-conforming mesh that wraps around the heart to deliver electrical impulses to the entire organ. The wrap is made of silver nanowires embedded in a rubber polymer, and was designed to conform to the unique anatomy of different hearts, according to a paper published online in Science Translational Medicine.

The researchers from the IBS Center for Nanoparticle Research induced cardiac arrest in rats whose hearts they had wrapped in the mesh. The epicardial device provided synchronized electrical stimulation with the high conductivity of 11,210 S/cm, shortening total ventricular activation time, reducing inherent wall stress, and improving several measures of systolic function, such as increases of 51% in fractional shortening, ~90% in radial strain, and 42% in contractility, according to the paper.

The mesh also acted as an epicardial defibrillator, re-establishing normal contraction rhythms in rat hearts with induced ventricular tachyarrhythmia, or rapid beating.

Even so, previous clinical trials "showed controversial results in long-term survival," the article says. "The researchers hope that their device, which is designed to integrate more faithfully with the heart's structure and electrical conduction system, is more consistent in people."

They're not first to the table with a heart wrap. Scientists at Washington University in St. Louis and the University of Illinois at Urbana-Champaign published an article in Nature in 2014 about how they used 3-D printing to construct a platform for deformable arrays of multifunctional sensors, electronic and optoelectronic components, "providing a mechanically stable biotic/abiotic interface during normal cardiac cycles" in ex vivo experiments.

Meanwhile, more traditional cardiac stimulation is getting smaller and wireless. In April, FDA approved Medtronic's Micra as the first pacemaker in the U.S. that does not require wired leads to provide an electrical connection between the pulse-generating device and the heart.

St. Jude Medical is still waiting for FDA approval of its wireless Nanostim pacemaker, which received the CE Mark in Europe in March, according to the company.

The devices--about the size of large vitamins and implanted inside the heart--forgo the need to run leads to the heart, avoiding problems such as infection. The devices both have long battery life--12 years for the Micra and 13 years for Nanostim.

Nancy Crotti is a contributor to Qmed.

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