The present invention relates to an adaptor device for electrode catheters, in particular for unipolar electrode catheters.
The art field of heart surgery embraces numerous types of cardiac catheter designed for connection at one end, generally by way of a flexible tube functioning as a biocompatible outer sheath, to an artificial pacemaker implanted in the body of the patient, and carrying a terminal electrode at the remaining end which is offered in direct contact (positively anchored in most instances), to the ventricular cardiac muscle.
In the particular case in point, the expression `unipolar` is used to describe a catheter of which the terminal electrode constitutes the negative pole or cathode of the cardiac pacemaker, and the positive pole or anode is provided by the casing of the pacemaker itself. The terminal or ventricular electrode consists in a sharp point, preferably affording elements such as will penetrate and thus establish a continuous and secure contact with the cardiac muscle, connected to the negative pole of the pacemaker by way of an electrically conductive spiral wound wire (e.g. platinum-iridium alloy). It is being found currently, where patients require the replacement of an existing pacemaker rendered unreliable by reason of its low charge, irregular operation or malfunction, that problems can arise due to incompatibilities between the connectors of electrode catheters implanted in the past and those of more recent design; reflecting the ever greater technological advances being made in this field, in effect, the newer catheters are much smaller than their predecessors as the overall dimensions of the newer pacemakers also become much smaller.
Remembering that the ventricular electrode becomes embedded in time beneath a layer of organic tissue and cannot be removed (such a step is inadvisable from the medical standpoint), it happens that the solution adopted in present-day surgical practice is almost invariably one of implanting a completely new electrode catheter in the cardiac cavity for connection to the new pacemaker, and simply leaving the former electrode in place, unused, alongside the replacement.
As an alternative expedient, the prior art embraces adaptor-reducer type connectors functioning as a mechanical interface between the existing pins of a previously implanted electrode catheter and the receiver contacts of a replacement pacemaker; this inevitably reflects a compromise, from technical and medical standpoints alike, as the new implant is impoverished somewhat by the large dimensions of the mechanical components used for the interface. Given the reliance of the patient on the pacemaker, moreover, artificial stimulation must be maintained for the maximum time possible whichever replacement technique is ultimately adopted; accordingly, any replacement operation, and especially the fitment of a mechanical adaptor, must be accomplished as swiftly as possible.
The object of the present invention is to overcome the problem outlined above by providing an adaptor device that can be secured to the unattached end of a unipolar electrode catheter already in situ and used to make the requisite electrical connection to pacemakers of the latest generation; such a device will be simple in embodiment, swiftly implanted in surgery, and able to ensure a suitably dependable connection. Equally, this same object embraces the creation of an electrode catheter with a terminal portion readily adaptable to the markedly compact pacemakers of the latest generation.