RU2766402C1 - Endocardial electrode for temporary transvenous pacing - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: invention relates to medical equipment, in particular to intensive care and cardiovascular surgery, namely to endocardial electrodes, and is intended for temporary electrical stimulation of heart in order to control activity of heart in conditions of acute and chronic problems with rhythm and conduction, caused by various diseases, or to accompany a range of cardiovascular interventions. Endocardial electrode for temporary transvenous pacing is made in the form of an elastic conductor in an insulating sheath with an active stimulating current-conducting tip on the distal end of the electrode. Immediately proximal to said active tip, a loop is formed on the electrode.EFFECT: reduced number of complications associated primarily with myocardial injury during electrode installation, ease of positioning, low frequency of dislocations with loss of stimulation and safety with possible excessive introduction during correction of position in intensive care unit without visual X-ray control, as well as simplification of the device manufacturing process.10 cl, 6 dwg

Description

The field of technology to which the invention belongs

The invention relates to medical technology, in particular to intensive care and cardiovascular surgery, namely to endocardial electrodes, and is intended for temporary electrical stimulation of the heart in order to control heart activity in acute and chronic rhythm and conduction problems caused by various diseases or to accompany a whole a number of cardiovascular interventions.

State of the art

From the existing level of technology known endocardial electrode Elvi 215-110 company "Elestim-cardio" for temporary pacing, which contains an internal coil coated with radiopaque insulating material polyurethane. The distal contact (cathode) is made of titanium and has a stimulation area of 12 mm ² . The distal end configuration allows easy conduction and positioning in the right ventricle. A medium hard electrode with an atraumatic “cournand” tip, which ensures reliable contact and reduces perforation of the heart muscle wall. The disadvantages of this technical solution are: instability of fixation, frequent dislocations, as the electrode is an electrode of medium hardness, which does not exclude damage to the myocardium.

http://www.elestim-cardio.ru/ru/catalog/elvi-215-110.html

Closest to the claimed technical solution is a bipolar ventricular endocardial electrode for temporary pacing TS-115 Ballon from Biotronik, which contains a coil covered with insulation connected to a contact element, and a stylet installed inside the coil with the possibility of axial movement. At the end of the electrode there is an inflatable latex balloon with a diameter of 8 mm for convenient positioning using blood flow. The main disadvantages of this technical solution are the possibility of developing right ventricular perforation when positioning the electrode, damage to the balloon during inflation and dislocation of the electrode, and the complexity of the technical design of this device, which requires clearance to fill the balloon along the entire length of the electrode.

https://cardiomed8.wixsite.com/system/kopiya-pacel-st-jude-medical

According to the literature, the frequency of perforation of the wall of the right ventricle during temporary pacing is 0.3-1%, which is a potentially fatal complication. (McCann P. A review of temporary cardiac pacing wires. Indian Pacing Electrophysiol J 2007; 7:40-49), (Aliyev F et al. Perforations of right heart chambers associated with electrophysiology catheters and temporary transvenous pacing leads. Turk Kardiyol Dern Ars 2011; 39:16-22). The incidence of temporary pacing lead dislocation is up to 9% (Jorge Lopez Ayerbe et al. Temporary Pacemakers: Current Use and Complications. Rev Esp Cardiol 2004 Nov; 57(11): 1045-52) and can also cause serious complications, with the frequency These complications are higher in patients with myocardial infarction, which make up the majority of patients requiring temporary pacing (Abinader E G et al., Temporary Transvenous Pacing: Analysis of Indications, Complications and Malfunctions in Acute Myocardial Infarction Versus Noninfartion Settings. Isr J Med Sci 1987 Aug 23(8):877-80).

Disclosure of invention

The problem to be solved by the present invention is to create an endocardial electrode for temporary transvenous pacing, which would reduce the number of complications associated primarily with myocardial injury during electrode installation, ease of positioning, low frequency of dislocations with loss of stimulation, as well as , simplifying the technological process of manufacturing the device and reducing its cost.

This problem is solved due to the fact that the endocardial electrode, namely its working area, is given an original target configuration in the form of a loop. This electrode for temporary transvenous pacing is made according to the classical, well-tested in practice scheme in the form of a conductive spiral in an insulating sheath with a contact element (active tip) located at the distal end of the electrode, and, as noted above, in the working contact area of the electrode (distal end device) a loop is formed. Thus, the endocardial electrode for temporary transvenous pacing is made in the form of an elastic conductor in an insulating sheath with an active stimulating conductive tip located at the distal end of the electrode, while a loop is formed on the electrode directly proximal to the specified active stimulating conductive tip.

The location and number of contact stimulating current-carrying elements on an electrode of the present form can vary widely. So this electrode can be provided with additional contact stimulating conductive elements located both on the loop and on the straight part of the electrode proximal to the loop.

The device can be made hollow - ie. have a blindly ending channel throughout (to the distal end of the device) without any side holes, or a channel with additional side holes located in the loop area or on a straight segment proximal to the loop for stylet placement with the possibility of modeling its shape (preshaping), with the possibility of its axial movement, designed to control both the shape of the electrode and / or its rigidity. The side holes at the distal end of the device can be used for both blood sampling and drug administration. When the stylet is completely immersed in the lumen of the canal, the latter does not go beyond the insulating sheath of the device and is fixed in the lumen of the device using the classic so-called. luer hub.

The total length of the electrode can be different and meet the requirements of the conditions of its use: i.e. - the main access, which is used to perform temporary pacing (femoral, subclavian, jugular, cubital, etc.).

Thus, the structural basis of this device is the shape of the distal part of the endocardial electrode (the so-called damping loop) for temporary transvenous pacing, where the force exerted by the tip of the electrode on the endocardium is a constant value, due to the rigidity (material elasticity) of the loop formed on the distal end of the device. The force that the operator transfers to the electrode by moving it forward, or, further, the force that provides the very elasticity of the material and the "excess length" created by the operator along the axis of the electrode, falls on the atraumatic "dome" of the very arc (or loop) formed at the distal end of the device.

The device can be implemented in several versions and have a different shape in two or three sections. The distal end of the electrode, having a length of 5-12 mm (depending on the diameter of the loop), is straight with an atraumatic tip. The part of the electrode directly proximal to the specified area is preliminarily formed in the form of a loop with a diameter of 6-15 mm. The part of the electrode proximal to the ring can be straight or have a 45° bend, traditional for this kind of instrument, relative to the main axis of the electrode (5-10 cm proximal to the ring) to facilitate right ventricular catheterization. Endocardial contacts are made of titanium or other corrosion-resistant electrically conductive material and are located in such a way as to increase the possibility of contact with the wall of the right ventricle. The inner spiral, which is a conductor, is covered with an insulating material (polyurethane or other material with similar properties) and may contain a pre-installed straight stylet with the possibility of its axial movement and giving it a certain curvature, which allows adjusting the rigidity of the structure and the shape of the end part of the electrode.

The proposed device guarantees safe catheterization of the right ventricle, low possibility of dislocation with loss of stimulation during operation, and safety with possible over-introduction during position correction in the intensive care unit without visual fluoroscopic control.

Brief description of the drawings

The invention is illustrated by drawings, which show:

fig. 1 is a diagram of the transfer of force to the active tip in the case of using an electrode known from the prior art;

fig. 2 is a diagram of the transfer of force to the active tip in the case of using the electrode according to the invention;

fig. 3 - general view of the device with a curved section of the proximal part of the electrode;

fig. 4 - general view of the device with a straight section of the proximal part of the electrode;

fig. 5, 6 - an embodiment of the device with a stylet.

Implementation of the invention

As shown in FIG. 1, in the case of using a conventional catheter, the main force F, aimed at stabilizing the general position of the catheter, is completely transferred to the active stimulating conductive tip of the catheter, which can be dangerous.

In the case of a loop (see Fig. 2), the main force F is transmitted only to the upper part of the loop (“dome” of the loop), and not to the active stimulating conductive tip of the stimulating catheter, which produces a constant pressure on the endocardium, due to the rigidity of the material, from which has a terminal damper loop, which is much safer. The magnitude of the force F _H on the active stimulating conductive tip does not depend on the main force. The force on the active stimulating conductive tip will have a constant value and will depend only on the stiffness of the distal part of the helix. The depth of unwanted penetration of the active stimulating conductive tip into the myocardium depends on its external length (outside the ring of the distal loop) or on the distance between the active stimulating conductive tip and the "dome" of the loop.

In the following specific embodiment of the device according to the invention, the loop is made in the form of a single coil, forming a closed circle. This example of an electrode is not intended to be limiting in terms of the scope of protection, since the loop may be open loop, such as U-shaped or Q-shaped, closed loop, turn, circle, etc. in various embodiments of the invention.

According to a preferred embodiment of the invention (see Figs. 3-6), the basis of the device is a metal spiral, which is a conductor, made of conductive metal. The helix is coated with an insulating material (polyurethane or other material of similar properties) and may, in one embodiment, form a channel for passing a straight stylet made of metal, such as steel. The electrode 1 has contacts 2, 4 made of titanium or other corrosion-resistant electrically conductive material, located in such a way as to increase the possibility of reliable contact with the wall of the right ventricle. The electrode 1 in the distal section is pre-formed in the form of a loop (loop-damper) 3 with a diameter of 5-12 mm so that its end protrudes beyond the loop by no more than 3-4 mm. It is also possible to design the device with the proximal part of the electrode 1 formed at an angle of 45 degrees. The proximal end of the electrode 1 is connected by any known method to a device for temporary pacing (not shown).

The total length of the electrode 1 can be from 600 to 1200 mm, which is sufficient for pacing the right ventricle using any conventional transvenous access. The length of the straight stylet 5 is obviously less than the full length of the electrode and can reach 1190 mm; the distal end of the stylet does not extend beyond the electrode itself, which eliminates the risk of complications during delivery and positioning. The adjustable stylet immersion depth allows changing the rigidity of the distal portion of the device and its configuration by straightening the loop 3 with a deeper immersion of the stylet and makes it possible to premodify the stylet shape, achieving the necessary bending when inserting into the cavity of the right ventricle in all possible anatomical variants. The length h of the active tip 2, i.e. of the distal straight conductive tip of the electrode is 5-12 mm, due to which, after removing the stylet, the straight tip protrudes beyond loop 3 by no more than 4 mm, which reduces the risk of perforation of the right ventricular wall, while ensuring reliable contact with it.

It is also possible to design the device with a proximal 45-degree pre-shaped portion, which improves the controllability and deliverability of the device.

Contacts 4 are located both on the straight part of the electrode and on loop 3, which increases the likelihood of reliable contact with the wall of the right ventricle and reduces the likelihood of loss of stimulation. It is also possible to design the device with contacts 4 in the area between the loop 3 and the part formed at an angle of 45 degrees, which further increases the likelihood of contact with the wall of the right ventricle.

The invention is used in the following way.

After securing venous access to the superior or inferior vena cava system by any available means, the assembled device is advanced to the right atrium using standard precautions. If there is resistance to the conduction of the device, partial or complete removal of the stylet 5 is possible, which changes both the geometry of the device and its rigidity. Thus, pulling the stylet 5 by 10-20 mm allows the loop 3 portions of the electrode to partially change shape (Fig. 5, 6), which improves the controllability and deliverability of the device. Further removal of the stylet 5 will allow the loop to fully form and take the shape of the 45 degree part of the electrode, which can also be used to manipulate the device upon delivery. If the angle of the catheter is insufficient, it can be increased by removing the stylet, creating the desired stylet angle and immersing the stylet into the channel, providing the electrode with the desired shape.

Once the device has reached the right atrium/ventricle through the inferior or superior vena cava systems, the stylet is fully or partially retracted, allowing lead 1 to take the desired shape. The depth of immersion of the stylet 1 allows you to adjust the rigidity and controllability of the device and the transmission of the pushing force. After that, the device is passed to the apex of the cavity of the right ventricle under fluoroscopic control, or focusing on the shape of the electrocardiographic curve, which is taken from the distal electrode. After inserting the device, the stylet 5 must be removed by at least 60 mm, which allows the preformed part of the electrode 1 to take the form of a loop 3, eliminating the risk of perforation of the right ventricular wall. Next, the device moves forward until the active tip 2 comes into contact with the endocardium of the right ventricle, after which the stylet 5 is completely removed and pacing is performed according to the accepted method.

Due to the fact that the portion of the electrode immersed in the cavity of the right ventricle has the form of a loop, where the distal tip of the electrode protrudes beyond its limits by no more than 4 mm, the risk of perforation of the wall of the right ventricle is minimal.

Also, due to the presence of contacts both on the tip of the electrode and on its preformed part, the probability of dislocation of the device with loss of stimulation is reduced.

Claims (10)

1. An endocardial electrode for temporary transvenous pacing, made in the form of an elastic conductor in an insulating sheath with an active stimulating conductive tip located at the distal end of the electrode, characterized in that a loop is formed on the electrode directly proximal to the specified active stimulating conductive tip. 2. An electrode according to claim 1, characterized in that said electrode is provided with additional contact stimulating conductive elements located on the loop. 3. An electrode according to claim 2, characterized in that said electrode is provided with additional contact stimulating conductive elements located proximal to the loop. 4. The electrode according to any one of paragraphs. 1-3, characterized in that the elastic conductor is made hollow to accommodate the stylet with the possibility of its axial movement, designed to control the shape of the electrode and/or its rigidity. 5. The electrode according to any one of paragraphs. 1-4, characterized in that the elastic conductor is made in the form of a spiral. 6. The electrode according to any one of paragraphs. 1-5, characterized in that the total length of the stylet is not more than 1199 mm. 7. The electrode according to any one of paragraphs. 1-5, characterized in that the total length of the electrode is 1200 mm. 8. The electrode according to any one of paragraphs. 1-7, characterized in that the length of the straight distal end of the electrode protruding beyond the loop is 2-4 mm. 9. The electrode according to any one of paragraphs. 1-8, characterized in that the loop diameter is 6-12 mm. 10. The electrode according to any one of paragraphs. 4-8, characterized in that the electrode has side holes in the area of the loop and/or on a straight segment proximal to the loop.

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