Devices to stimulate and/or regulate cardiac function are known in the prior art. Such devices typically include a power source, such as a pacemaker, and one or more surgical electrodes attached to the pacemaker and to a patient's heart. Generally, there are two types of devices to stimulate or regulate cardiac function; namely, permanent pacemakers and temporary pacemakers.
The permanent-type of pacemaker is implanted entirely within a patient's body and is intended for long-term use. The temporary pacemaker is located outside the patient's body and is connected to the heart by a surgical electrode called a “temporary pacing wire” because it is intended for short-term use (e.g., 1 to 10 days). As used herein, the phrase “temporary cardiac pacing wire” shall mean those pacing wires specifically designed and intended for short-term use within the body and not those pacing wires specifically designed and intended for chronic implant. Although surgical electrodes are used for preparing electrocardiograms and other applications, the description that follows will, for the sake of brevity, focus on temporary pacing wires.
In general, temporary pacing wires are constructed from a number of fine, stainless steel wires braided or twisted together to form a single, flexible, multi-strand electrode wire. The major portion of the wire is electrically insulated with a polyethylene, polytetrafluorethylene, silicone, nylon, or other non-conducting coating, a short length of wire at either end being left uninsulated. To the distal end of the electrode wire, there is attached, by swaging or other means, a fine curved needle for piercing the heart tissue to place the electrode in the myocardium. At the proximal uninsulated end of the electrode wire, a straight (e.g., Keith-type) cutting needle is attached for piercing the thoracic wall to lead the electrode wire outside the body for connection with the pacemaker. Once that has been accomplished, the needle, or its sharp-pointed end, is clipped or broken off and the proximal end of the electrode wire is readied for attachment to the pacemaker as required to stimulate or regulate the beating of the heart.
During the time that the temporary pacing wire is performing its function, the distal end of the electrode must remain securely attached to the heart. The retention force must be sufficient to prevent the temporary pacing wire from being accidentally detached by the continually beating heart. When there is no longer a need to stimulate or regulate the heart, it is necessary to remove the temporary pacing wire that runs from the external pacemaker to the heart. The removal of the temporary pacing wire should be accomplished with minimal heart trauma.