Though an average of 150,000 patients receive cardiac resynchronization therapy (CRT) implants each year, in order to keep their heart chambers pumping in synchrony, that still leaves 50,000 who do not benefit from this expensive and invasive procedure.
Now, a new device has been developed to target those who did not improve after the CRT device implantation—those who are called “non-responders.” The device is called WiSE (Wireless Stimulation of the Endocardium); it’s about the size of a grain of rice and is controlled by ultrasonic pulses that moderate the heartbeat.
Results revealed that after applying WiSE on patients who didn’t improve after CRT device implantation surgeries or who simply didn’t qualify for the surgery itself, the condition of 85% of the patients improved greatly.
As WiSE is already available in Europe, cardiologists from the U.S. together with the Food and Drug Administration (FDA) are already working on a clinical trial that’s to begin by the year 2017.
CRT implants require three electrodes to be attached to a patient’s heart. These electrodes are attached by leads that maintains the synchronized beating of the heart’s chambers. The first two leads are inserted into the right atrium and ventricle. The third lead, on the other hand, is much harder to place, since it is inserted through a vein that wraps around the heart. Precision is key in this step, because if the third lead is placed where scar tissue is present, it won’t be able to stimulate the heart.
Placing a foreign object directly in the heart chamber is risky in itself since blood clots can form around these devices. Once the clots break away from the device, they travel through the blood vessel and can potentially cause clogs, leading to further heart failure.
WiSE has a tiny electrode that attaches to the inner wall of the left ventricle. A polyester scaffold is then placed over it to allow the heart cells to grow over and encapsulate it. It also isn’t as complicated as CRT implants that have a battery or a processor. Instead, WiSE has 47 piezoelectric elements that produce an electric charge when it senses mechanical stress.
WiSE can also work with previously implanted CRT devices and pacemakers that don’t keep up the task of maintaining a synchronized heartbeat within a patient’s heart. WiSE can detect the signals emitted by these devices and coordinate pulses to the left ventricle for every heartbeat. WiSE is able to replicate the natural activation of the heart much more closely when compared to CRT implants because WiSE is nestled inside the heart, generating a wave of electricity that starts from inside the heart and radiates outward, mimicking a natural heart beat.
CRT implants, on the other hand, work differently. According to Jagmeet Singh, a cardiologist at Massachusetts General Hospital and the team leader of the trial, “With conventional CRT the electrode is on the outside of the heart, so the signal goes from the outside in. But that’s against mother nature.”
The process of FDA approval is a lengthy one, and it may be some time before the WiSE implant becomes widely available in the U.S.; still, it’s a promising technology that may provide new hope for those who either cannot receive or did not respond to CRT implants.