The electrical leads for cardiac stimulators comprise an insulated electrical conductive section and a lead-in securing section including a helical member which may be screwed into the heart muscle. Preferably, there is interposed between these two sections a non-insulated electrical conducting section which becomes embedded in the heart upon insertion of the electrical lead. If there is any breakage between the lead-in securing section and the rest of the electrical lead, electrical impulses are still supplied to the heart by the cardiac stimulator.
An insertion tool is provided to attach the electrical lead to the heart.
This invention relates to methods and means for attaching a pacemaker or cardiac stimulator to the heart of animals and humans. It also relates to a cardiac stimulator system for S-A node heart blockage and a method for resisting coronary insufficiency.
The beat of human and animal hearts is controlled by electrical impulses entering the atrium and passing through to the ventricles. When the travel of these electrical impulses from the atrium to the ventricles is partially or totally impeded this condition is referred to as a "heart block". For some time heart blocks have been corrected by attaching "cardiac stimulators", small generators of electrical impulses, through electrical leads to the malfunctioning heart.
Cardiac stimulators have been used to pace the heart in synchronous and non-synchronous manners. In synchronous pacing suitable equipment is connected to the atrium to pick up the beat of the atrium. This electrical beat is coordinated with electrical impulses sent by a cardiac stimulator attached to the ventricles to achieve "synchronous" beating between the atrium and the ventricles.
In non-synchronous pacing the cardiac stimulator is merely attached to the ventricle and the beating of the ventricles and atrium is not in complete harmony. The efficiency of the heart is reduced in non-synchronous pacing approximately 20%, but since it requires fewer attachments to the heart non-synchronous pacing has been the most commonly used pacing system.
Heretofore a thoracotomy was commonly required to attach a cardiac stimulator to the heart and the electrical leads were sutured into electrical contact with the heart. This technique has numerous disadvantages. Firstly, a thoracotomy, which requires a large incision in the chest or thorax, is drastic surgery and has a relatively high mortality rate. Secondly, suturing the electrical leads into the electrical contact with the heart causes severe trauma to the heart, which it is desirable to minimize.
An intravenous connection has also been used to attach electrical leads of a cardiac stimulator to the heart. In this technique the electrical lead is passed through a vein into the heart where it is held by fibrilla located in close proximity to the heart valve through which the lead is passed. There are, however, many disadvantages to this technique also, including: the possibility of damage to the vein during insertion, such as vein perforation; the failure to securely attach the electrical lead to the heart; and the possibility of perforating the heart wall with the electrical lead during insertion or after attachment has been completed.
It is therefore desirable to provide methods and means for attaching a cardiac stimulator to the heart of an animal or human which do not require a thoracotomy, have less traumatic effect upon the heart and securely attach the electrical leads to the heart.
It is therefore an object of the present invention to provide an electrical lead for a cardiac stimulator which may be securely attached to the heart of an animal or human without the trauma caused by suturing an electrical lead onto the heart.
It is a further object to provide an electrical lead for a cardiac stimulator which may be attached to the heart through less drastic surgical procedures than a thoracotomy.
It is another object to provide an electrical lead for a cardiac stimulator which may be easily, yet firmly, attached to the heart.
It is yet another object to provide an improved electrical lead utilizing an insertion tool for securing the lead to the heart.
It is another object to provide a cardiac stimulator system which is corrective of S-A node blockage.