Surgery – Truss – Pad
Patent
1989-08-28
1992-10-27
Kamm, William E.
Surgery
Truss
Pad
128642, 128696, A61B 504
Patent
active
051580926
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a device permitting localization of the emergence point of ventricular tachycardias in cardiological medicine, by a successive approach method, characterized, in comparison with traditional cardiac mapping, by: a precision of the same order, its speed of use, its low cost and the further possibility of localizing the macro-re-entry pathway (around aneurysms, for example).
In distinction to traditional mapping, this device dispenses with the construction of a map of isochrones.
The techniques currently used are either manual or automatic, and are applied to the epicardium, the endocardium or the myocardium itself: A) Epicardium/Manual method: a three-pole probe is moved on the surface of the heart, while a reference electrode is attached close to the base of the aorta.
An electrocardiograph comprising: probe, measured at the time which has elapsed (interval) between the depolarizations perceived by the reference electrode and the mobile electrode.
Several interval values enable a map of isochrones (equal interval curves) to be constructed, giving a two-dimensional view of the propagation of the depolarization. The point on this map corresponding to the shortest interval is considered to be the emergence point, which is accordingly subjected to surgical removal. This removal may be carried out by ventriculotomy with a scalpel, by diathermy or by a cryosurgical technique.
B) Epicardium/Automatic method: an epicardial net supports from 50 to more than 300 electrodes each connected to an instrumentation amplifier. Each route is multiplexed, sampled/blocked and converted to digital form. A processor acquires these data, processes them and displays them on a monitor or printer in list or image form.
C) Myocardium: a needle equipped with several electrodes provides information about the depth of the emergence point in the thickness of the myocardium.
D) Endocardium/Manual method: a catheter is positioned at different points of the endocardium. The location corresponding to the earliest interval, relative to the reference catheter, is subjected to fulguration.
E) Endocardium/Automatic method: an endocavitary inflatable balloon containing several tens of electrodes permits localization of the emergence point using the acquisition system described in B).
The principle of the device according to the invention is based on localization of the propagation of the myocardial cell depolarization, or of the muscle contraction of the heart which results directly therefrom. This localization is carried out in stages over the entire length of its pathway from an arbitrary point on the heart chosen by the operator, retracing this pathway as far as its source, which is referred to as the emergence point.
The device according to the invention comprises a probe connected to electronic circuits which are designed to process the signals gathered by the probe and to control a device/operator interface. The device according to the invention is referred to as an "azimuthal probe", the two words not being separated in this case. The term "probe" is reserved for an assembly comprising the sensors, their support, the electrical linking cable with its connector and any means of signalling which are attached thereto and intended for the operator.
The probe is composed of at least one assembly of two sensors sensitive to myocardial depolarization (electrochemical phenomenon) or to cardiac contraction (mechanical phenomenon which is the consequence thereof). Each assembly of two sensors is arranged on an approximately rectilinear axis. The sensors are attached to a support which the operator moves over the epicardium or over the endocardium.
The azimuthal probe enables the following to be determined: the cardiac muscle contraction which results directly therefrom, the common source of which is the activation of the emergence point; this sense is determined along the direction represented by the axis of the two sensors, when the operator can note the order of arrival of the activation potentials under one sensor
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de Bakker et al., "Endo. Card. Mapping by Simul. Recording of Endo, ECG's During Card. Surgery", Journal of the Amer. Col. of Card., vol. 2, #5, Nov. 1983.
Savard et al., "Interactive Electrophys Mapping Sys.", IEEE 1985 Compint Computer Aided Technologies, Montreal, Quebec, Canada, 9-13, Sep. 1985, pp.76-78.
Kamm William E.
Schaetzle Kennedy J.
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