NON-INVASIVE CARDIAC PACING
BACKGROUND OF THE INVENTION
The present invention relates to non-invasive cardiac pacing, and is particularly directed to a method and device for transmitting electrical stimulation pulses to a heart ventricle, and monitoring cardiac function, by insertion of electrodes via the patient's esophagus, thereby avoiding the need for any surgical intervention.
It is already known in the art that atrial cardiac pacing can be performed by a procedure known as transesophageal 10 pacing, in which one or more electrodes are introduced into a patient's esophagus to bring the electrodes to a point in the esophagus which is directly adjacent to the left atrium of the heart. A device of this type is disclosed in U.S. Pat. No. 4,706,688. 15
When electrodes are brought to such a position and are pressed against the wall of the esophagus, cardiac stimulation pulses can be applied to the heart atrium. When a condition requiring atrial pacing is encountered, this technique can prove advantageous since it allows pacing to be 20 initiated rather quickly without requiring surgical intervention and the trauma associated therewith.
However, while there are certain situations in which ventricular pacing is indicated, there are no existing devices or procedures which allow ventricular pacing to be achieved 25 safely in a manner similar to the transesophageal pacing technique described above.
BRIEF SUMMARY OF THE INVENTION
It is a primary object of the present invention to make 30 possible ventricular pacing by means of a device which can be inserted through a patient's esophagus in order to bring an electrode or electrodes into position to effect ventricular pacing.
Another object of the invention is to provide a device for 35 this purpose which is constructed to be safely and comfortably introduced into the patient's esophagus via a naris.
A further object of the invention is to enable effective ventricular pacing to be achieved by the application of low current pulses. 40
The invention is based in part on the realization that electrodes can be suitably mounted to enable them to first safely pass through the esophagus into the stomach and to then be pressed against the stomach wall at a location proximate to the patient's ventricle. 45
Thus, the above and other objects are achieved, according to the present invention, by a device for effecting ventricular cardiac pacing, comprising: cardiac pacing electrodes; a carrier supporting the electrodes in a manner to permit the electrodes to be inserted into the stomach of a patient via the 50 patient's esophagus; and carrier displacing means supporting the electrodes and operable for pressing the electrodes against the wall of the stomach at a location adjacent a heart ventricle.
Objects according to the invention are further achieved by 55 a method for effecting ventricular cardiac pacing comprising: inserting electrodes into a patient's stomach via the patient's esophagus; pressing the electrodes against a portion of the wall of the stomach which is adjacent a heart ventricle; and delivering electrical impulses to the electrodes 60 for transfer to the heart ventricle as pacing pulses.
BRIEF DESCRIPTION OF THE SEVERAL
VIEWS OF THE DRAWING
FIG. 1 is a pictorial, cross-sectional view showing the 65 components of one embodiment of a device according to the invention in a position to effect ventricular pacing.
FIG. 2 is a block diagram of one embodiment of a testing system according to the present invention.
DETAILED DESCRIPTION OF THE
The device shown in FIG. 1 is composed basically of a tube, or catheter, 2 having a flexibility sufficient to enable it to be advanced through a patient's naris (not shown) and then through the patient's esophagus 12 so as to bring the leading, or distal, end of tube 2 into the patient's stomach 14. Balloon 6 is mounted on the distal end portion of tube 2. Balloon 6 may be inflated via an airway 8 that extends to the proximal end of tube 2, which would be located outside of the patient's body. The proximal end of airway 8 may be provided with an inflation bulb or other inflation device of the type commonly employed in medical equipment. In FIG. 1, balloon 6 is shown in its fully inflated state.
Tube 2 is provided, on its outer surface, with several annular electrodes 16, each connected to one respective conductor 20 that passes though tube 2 and extends to the proximal end of tube 2. The number, form and spacing of electrodes 16 will be selected on the basis of principles already known in the art.
The patient's heart 24 is normally located relative to esophagus 2 and stomach 14 in substantially the manner shown in FIG. 1, with its left ventricle in close proximity to, or in contact with, the wall of stomach 14, its right ventricle in proximity to the wall of stomach 14 and its left atrium close proximity to, or in contact with, esophagus 12.
According to the invention, two or more electrodes 16 are pressed, as a result of inflation of balloon 6, against the inner surface of the portion of the wall of stomach 14 which is in proximity to, or in contact with, at least the left ventricle of heart 24, and possibly also against the inner surface of the portion of the wall of stomach 14 which is in proximity with the right ventricle of heart 24. Balloon 6 may be given a compliance and may be dimensioned so that balloon 6 will, upon being inflated, act to slightly distend the associated the portion of the wall of stomach 14 to an extend sufficient to place that stomach wall portion in contact with the outer surfaces of one or both ventricle chambers. Then, electrical impulses conducted to electrodes 16 via conductors 20 will be conducted to heart 24 through the stomach wall to act as ventricular pacing pulses.
Due to the fact that balloon 6 can press electrodes 16 firmly against the stomach wall, and can press the stomach wall against at least one ventricle, electrodes 16 can be given small dimensions and low level pacing currents can be used.
Tube 2 of a device according to the present invention could be constructed on the basis of principles well known in the art and can be constituted by any tubular body having the requisite flexibility. This tube could be constituted, for example, by a device known as a tapscope, examples of which are marketed by the Arzco Corporation. Tube 2 could also be identical to a known tube used for transesophageal pacing, as disclosed in the above-cited U.S. Pat. No. 4,706, 688. Tube 2 may also be a flexible catheter made of electrically insulating material.
Balloon 6 can be secured to a distal end portion of tube 2 in any suitable manner already known in the art for securing balloons to catheters and other medical devices. When balloon 6 is not inflated, it will not offer any impediment to insertion of the device through a naris and then through the esophagus. In addition, When balloon 6 is not inflated, tube 2 will assume its normal generally straight configuration, thus allowing it to pass easily and safely through the