Prevent Deadly Heart Arrhythmias?
Heart disease and the complications caused by heart disease is the number one killer in the United States. The Center for Disease Control reports that someone in the US dies of a heart attack every 40 seconds, and approximately 805,000 people in the US have a heart attack annually. While heart disease is the primary cause of heart attack, electrical misfiring leads to irregular heartbeats, thus, making up a significant proportion of heart-related deaths.
Physiologically, the heart’s natural pacemaker is the sinoatrial (SA) node located on top of the heart’s atrium conducting the electrical impulse downwards into the atrial and ventricle chambers of the cardiac muscle. Scarification or damage to all or part of this region prevents the transmission of this electrical signal causing an irregular heartbeat or arrhythmia, leading to a heart attack or stroke.
Currently, medications to control heart rhythm, surgically implanted pacemakers, and defibrillators, as well as ablation therapy, are used to control and prevent heart-related arrhythmias. Unfortunately, each of these procedures has its own cons, especially defibrillators that produce both a powerful and painful shock without warning, leaving the patient with depression and anxiety. However, with the advancement of technology, there is a need to implement new and novel technological approaches to mediate cardiac arrhythmias.
To circumvent the issues caused by implanted defibrillators, Cosgriff-Hernandez, a biomaterial engineer, and her colleagues at the University of Texas, Austin, have developed a polymeric liquid gel that can be injected into the coronary vein where it solidifies into a thin, flexible conductive plastic wire. The polymer consists of two liquid phase components. The first liquid polymer is poly(ether urethane diacrylamide) or PEUDAm, forming the plastic wire. The second liquid polymer is N-acryloyl glycinamide, which crosslinks the residues within the gel, hardening the wire. Interestingly, both remain in a liquid state until they are mixed.
Using the heart of a live pig, they inserted both liquid polymers through a catheter that kept them from interacting. Once the catheter was removed, it allowed both to mix and react, forming a stable, conductive, nontoxic, and biocompatible flexible wire within the heart. In order to mimic a real-world diseased heart, they scarred the cardiac tissue of a pig and repeated the catheter injection process. After the wire hardened, they connected the wire to a standard battery-powered pacemaker and achieved a near-normal heart rhythm.
Unfortunately, this application within a human heart is not yet available and is aways off from clinical applications. The long-term safety and stability of the injectable polymer needs to be studied in both animals and humans; however, this is may be a significant first step toward revolutionizing how cardiologists regulate arrhythmias caused by one of the most prevalent disease states within the US.