In March 1998, the U.S. Food and Drug Administration gave premarket approval (PMA) to the new Mark IV external transmitter for adult and pediatric patients who have lost neurological control of respiration. FDA premarket approval is required before Class III medical devices can be commercially distributed in the United States.
In advance of FDA approval, the Mark IV had been distributed in 24 countries worldwide. The Mark IV qualified for the CE Mark under the European Active Implantable Medical Device Directive in 1994.
The implanted receiver is a small electronic device, about the size of a US quarter and approximately 1/4″ thick, that receives radiofrequency energy and converts it to electrical impulses which stimulate the diaphragm.
The implanted electrode is a highly flexible stainless steel wire, insulated by silicone rubber, with a platinum nerve contact on one end, and a connector that mates with the receiver at the other.
The I-110 family of receivers were implemented for phrenic pacing in 1990 and approved by the US FDA in 1991. Obsolete I-107 receivers are pin-compatible with the current design and can be upgraded in a simple outpatient surgical procedure.
A bipolar configuration is also available for those patients implanted with other medical devices, such as a cardiac pacemaker, to provide an additional margin of electrical isolation.
An external antenna is worn over each implanted receiver and sends power and radio signals from the transmitter to the receiver transcutaneously. This radiofrequency coupled design means that there are no wires or plugs protruding from the skin, and no batteries in the implant that would require periodic replacement.
An antenna is a durable disposable item which requires periodic replacement. It is recommended that antennas be replaced prophylactically every six months. Antennas are available in one-meter and two-meter lengths.
Antennas do not contain latex. Additionally, no latex products are used in their manufacturing. Instructions for the use and care of antennas can be found here.