The adult heart usually beats between 60 and 100 times a minute at rest, but if a person has bradycardia, a slower than normal heart rate, it indicates a problem with the heart’s electrical system.
Bradycardia could mean that the heart’s natural pacemaker is malfunctioning or that the heart’s electrical pathways may be disrupted. In severe bradycardia, the heart beats so slowly that it doesn’t pump enough blood to meet the body’s demands, and this can pose serious health issues.
To overcome this problem, several million Americans rely on a surgically implanted cardiac pacemaker and it’s this device that keeps the heart beating at a steady clip.
The technology involved in cardiac pacemakers has not changed all that much since the first device was implanted in 1958. A typical pacemaker consists of a pulse generator the size of a sliver dollar that sits snugly below the collarbone and is secured in a surgical pocket under the skin. The thin wires inserted through a vein—the leads—are stretched from the pulse generator to the heart.
The leads detect a patient’s heart rhythm and relay the information to the generator and enclosed computer chip, which then adapts its electrical responses to the patient’s needs so the heart continues to beat at a normal rate.
Leads, which also deliver the electrical impulses that prompt the heart to beat, are cables comprised of multiple thin wires covered by insulation. The tip of the lead is anchored to a section of heart muscle, while the rest of the cable floats freely in the vein.
Over time, the polyurethane and silicone leads can break, the insulation around them can crack, and they can become infection sites, which happens in 2 percent of cases. Dislodgement of leads can occur in upwards of 3 percent of cases. It’s not impossible to replace broken, failing or obsolete leads, but it is a very difficult and time-consuming procedure.
Understanding the inherent problems with the traditional cardiac pacemaker, the approval for use last year in Europe of a tiny leadless and self-contained cardiac pacemaker was heralded throughout the global cardiac community.
This wireless cardiac pacemaker that’s no bigger than a large vitamin is 10 percent the size of a traditional pacemaker. In the space of 15 to 30 minutes, the miniaturized battery-controlled device can be implanted directly in the heart without surgery by steering it through a femoral vein and up into the heart’s right ventricle.
Secured in place by prongs or a screw, a sensor electrode in the metal-clad device detects all heart rate information and relays it to the generator, which provides the necessary cardiac stimulation to keep the heart in regular rhythm.
Lithium battery life is estimated to be seven years or longer with the current miniaturized devices. The entire wireless pacemaker is fully retrievable via a catheter and a new one can be inserted when the battery wears out. Or, in lieu of replacement, another leadless pacemaker may simply be implanted when needed.
This pacemaker nanotechnology has eliminated surgery, lumps and scars on patient’s chest, restrictions on daily physical activities, as well as any complications stemming from any malfunctioning insulated connecting leads. Not yet approved in the United States by the Food and Drug Administration (FDA), late-stage clinical trials of several leadless pacemakers for patients experiencing heart rhythm issues are now ongoing testing at scores of sites around the country, each in pursuit of FDA approval.
Where Are They Now
Two leadless pacemaker devices currently dominate the space. Having already received the CE mark in Europe, the FDA approved the first leadless pacemaker in April of 2016. Though also CE marked, the second has yet to receive FDA approval. In January 2017, the US Centers for Medicare and Medicaid announced the coverage of leadless cardiac pacemakers. This decision will provide access to these medical devices for Medicare patients.