JP2001190695A - Biphasic electrical cardiac pacing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biphasic electrical cardiac pacing. SOLUTION: An apparatus for muscular stimulation contains means for defining a first stimulation phase with a first phase polarity, a first phase amplitude, a first phase shape and a first phase duration for pre-conditioning myocardium to accept subsequent stimulation, means for defining a second stimulation phase with a polarity opposite to the first phase polarity, a second phase amplitude that is larger in absolute value than the first phase amplitude and a second phase duration and means for applying the first stimulation phase and the second stimulation phase in sequence to a cardiac tissue. The two phase stimulation is applied sequentially. Anodal stimulation is first applied and followed by cathodal stimulation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates generally to a device for stimulating muscle tissue, and more particularly to a device for stimulating muscle tissue.
The present invention relates to a device for stimulating and pacing myocardium using a two-phase waveform, thereby improving conductivity and contractility.

[0002]

BACKGROUND OF THE INVENTION Cardiovascular function is extremely important for survival. Through blood circulation, body tissues take in the necessary nutrients and oxygen,
Discard the waste. When this circulation stops, the cells begin to undergo irreversible changes and eventually die. Myocardial contraction is the driving force behind this.

In the myocardium, muscle fibers are connected to each other as a branched network, which extends in all directions throughout the heart. If any part of this network is stimulated, the depolarization wave will propagate to all parts of the heart, and the entire structure will contract as a unit. Before the muscle fibers can be stimulated to contract, the membrane of the muscle fibers must be polarized. Normally, muscle fibers remain polarized until stimulated by some change in the environment in which they are placed. The membrane is stimulated by electrical, chemical, mechanical stimuli, or changes in temperature. The minimum stimulus intensity required to cause contraction is called threshold stimulation. The maximum stimulation intensity that could be managed without causing contraction is the subthreshold maximum amplitude.

When the membrane is electrically stimulated, the magnitude of the shock required to elicit a response depends on a number of factors.
The first is the duration of the current. An increase in stimulation duration is associated with a decrease in threshold current amplitude because the sum of the mobile charges is equal to the current amplitude multiplied by the pulse duration. Second, the proportion of the applied current that actually passes through the membrane varies inversely with the size of the electrode. Third, the percentage of the applied current that actually passes through the membrane changes in proportion to the proximity of the electrode to the tissue. Fourth,
The magnitude of the shock required to elicit a response depends on the timing of the stimulus within the excitatory cycle.

The majority of the heart is dedicated clumps and fibers of myocardial tissue. This tissue constitutes the heart conduction system, and serves to generate a depolarizing wave and give it to the entire myocardium. Interference or interference in the shock conduction of the heart can cause arrhythmias or significant changes in the speed or rhythm of the heart.

[0006] Patients suffering from conduction disorders may be rescued by artificial pacemakers. This type of device has an electrical stimulus generator driven by a small battery. When a prosthetic pacemaker is worn, the electrodes are usually passed through the blood vessels into the right ventricle or into the right atrium and right ventricle and the stimulus generator is implanted subcutaneously in the shoulder or abdomen. The conductor is implanted so as to adhere to the myocardium. The pacemaker then sends a regular electrical shock to the heart, responding that the myocardium contracts regularly. Implantable medical devices for pacing the heart are well known in the art and have been applied to the human body since the mid-1960s.

[0007] Both the cathode and anode currents can be used to stimulate the myocardium. However, anodic current is not considered clinically effective. The cathodic current consists of negatively polarized electrical pulses. This type of current causes the polarity of the cell membrane to be lost by discharging the membrane capacitor, causing the membrane potential to drop directly to a threshold level. The cathode current is
By lowering the resting membrane potential directly to the threshold, the latter has a threshold current that is one-half to one-third lower than the anodic current in late diastole. The anodic current includes an electric pulse having a positive polarity. The effect of the anodic current is to make the resting film highly polarized. When the anodic pulse ends abruptly, the membrane potential returns to the resting level, crosses the threshold, and a propagation reaction occurs. The use of anodic currents to stimulate the myocardium is generally not recommended because of the high stimulation thresholds and the use of high currents, which drains the battery of the implanted device and shortens its life. In addition, the use of anodic currents for cardiac stimulation is not recommended because anodic currents are depolarizing and may also cause arrhythmias, especially at high voltages.

[0008] Nearly all artificial pacing uses a negative stimulus pulse, or in a bipolar system, the cathode is the distal pole and the anode is separated from the myocardium. In the example where the use of anodic current is disclosed, it is typically used as a very small charge to eliminate residual charge on the electrode. It does not affect the myocardium itself or affect its state. For such use, see US Patent No. 4,545,395 to Herskovich.
No. 6 discloses.

Three layer waveforms are disclosed in U.S. Pat. Nos. 4,903,700 and 4,821,724 to Wiham et al. And U.S. Pat. No. 4,433,312 to Kars et al. In this case, the first phase and the third phase have nothing to do with the myocardium itself, and are only expected to affect the electrode surface itself. Thus, the charge provided in both phases is of a very low magnitude.

Finally, U.S. Pat.
No. 02322 discloses biphasic stimulation. The purpose of this disclosure is to create twice the voltage in the output circuit without large capacitors. Both phases of the disclosed biphasic stimulation are of equal intensity and duration.

The myocardial function is improved by the two-phase pacing action of the present invention. The combination of stimulable or tunable cathodic and anodic pulses keeps the conduction and contraction improvements due to anodic pacing while avoiding the disadvantage of increased stimulation threshold. The result is an increase in depolarizing wave velocity. This increase in propagation velocity significantly improves the contraction of the heart and results in improved blood flow. Providing sufficient stimulation at low voltage levels results in reduced power consumption and extended pacemaker battery life.

With respect to the myocardium, the striated muscle can also be stimulated by electrical, chemical, mechanical stimulation, or by temperature changes. If a muscle fiber is stimulated by a motor neuron (neural unit), all muscle fibers under which the neuron is under control (ie, muscle fibers within its own motor unit)
Activate to convey the shock. Depolarization in one area of the membrane stimulates adjacent areas to depolarize as well, with depolarization waves traveling on the membrane in all directions from the stimulation site. Thus, when a motor neuron transmits one shock, all fibers in the motor unit are stimulated and simultaneously contract. The minimum intensity that causes contraction is called threshold stimulation. It is a common wisdom that once the stimulus level is reached, increasing that level does not increase contraction. Further, the muscle fibers within each muscle are organized into multiple motor units, and since each motor unit is controlled by a single motor neuron, all muscles within one motor unit are stimulated simultaneously. However, the entire muscle is controlled by a number of different motor units that respond to different stimulation thresholds. Therefore, when a given stimulus is given to a muscle, some motor units may respond and others may not.

[0013] The combination of yin and yang pulses of the present invention results in improved muscle contraction when electrical muscle stimulation is directed due to nerve or muscle damage. If the nerve fibers are damaged due to trauma or disease, the muscle fibers in the area served by the damaged nerve fibers are:
Atrophy progresses and tends to disappear gradually. Unmoved muscles can be reduced to half their normal size within months. In the absence of irritation, the muscle fibers not only shrink in size, but also become fragmented and no longer regenerated and replaced by connective tissue. Electrical stimulation can maintain muscle tone, leaving live muscle tissue when nerve fibers are repaired or regenerated.

When muscle tissue is damaged by injury or disease,
The regeneration process can be assisted by electrical stimulation. Increased muscle contraction is achieved by the biphasic stimulation of the present invention. Combination of stimulation or adjustment Yin Yang pulse
Lower voltage levels result in more motor units contracting, which makes the muscles very responsive.

Accordingly, it is an object of the present invention to improve the stimulation of heart tissue. It is another object of the present invention to increase cardiac output through good systole, thereby resulting in increased stroke volume. Another object of the invention is to increase the speed of impact propagation. Another object of the present invention is to extend the battery life of a pacemaker.
Yet another object of the present invention is to provide effective cardiac stimulation at lower voltage levels. Another object of the present invention is to eliminate the need to keep electrical leads in close contact with tissue to obtain tissue stimulation. Still another object of the present invention is to improve stimulation of muscle tissue. Yet another object of the present invention is to provide for the contraction of more muscle motor units at lower voltage levels.

[0016]

SUMMARY OF THE INVENTION A muscle stimulator according to the present invention comprises a first phase polarity, a first phase amplitude, a first phase shape, and a first phase for preconditioning the myocardium to receive the next stimulus. Means for defining a first stimulus phase having a phase duration, a polarity opposite to the first phase polarity, a second phase amplitude greater in absolute value than the first phase amplitude, a second phase shape, and a second phase duration. Means for defining a second stimulation phase having: and means for sequentially applying the first stimulation phase and the second stimulation phase to the heart tissue.

[0017] The muscle stimulating method and apparatus according to the present invention comprises:
Includes applying biphasic stimulation to muscle tissue by applying both cathodic and anodic pulses. According to one aspect of the invention, the stimulus is provided to the myocardium to enhance the function of the myocardium. Thus, heart stimulation can be performed without attaching the conductive wire closely to heart tissue.
According to yet another aspect of the invention, striated muscle is stimulated to elicit a muscle response.

The method and apparatus of the present invention include a first and a second stimulus phase, each stimulus phase having a polarity, amplitude, shape and duration, respectively. In a preferred embodiment, the first and second phases have different polarities. In one alternative instance,
The amplitudes of the two phases are different. In a second alternative, the durations of the two phases are different. In a third alternative, the first phase is shown with a cutting waveform. In a fourth alternative, the amplitude of the first phase is ramped.
In a fifth alternative, the first phase stimulus is applied for more than 200 milliseconds after the heart beat. In a preferred alternative, the first phase stimulus is a sub-threshold maximum amplitude, long duration anodic pulse, and the second phase stimulus is a high amplitude, short duration cathode pulse. Note that the alternative examples may be combined in various ways. Also, these alternatives are provided by way of example only and should not be construed as limiting.

The electronics for pacing devices (pacemakers) that need to carry out the method of the invention are well known to those skilled in the art. Current pacing device (pacemaker) electronics can be programmed to generate various pulses, including those disclosed herein.

The present invention relates to two-phase electrical stimulation of muscle tissue. FIG. 1 shows a two-phase electrical stimulus in which a first stimulus phase, including an anodic stimulus 102, is provided with an amplitude 104 and a duration 106. Immediately after this first stimulus phase, a second stimulus phase is provided that includes a cathodic stimulus 108 of equal intensity and duration.

FIG. 2 shows a two-phase electrical stimulus in which a first stimulus phase including a cathodic stimulus 202 of amplitude 204 and duration 206 is provided. Immediately after the first stimulus phase, a second stimulus phase is provided that includes an equal intensity and duration of anodal stimulus 208.

FIG. 3 shows an amplitude 304, duration 306,
3 illustrates a preferred embodiment of the present invention in which a first stimulation phase comprising a low level and prolonged anodic stimulation 302 is provided. Immediately after this first stimulus phase, a second stimulus phase is provided that includes a conventional intensity and duration of cathodic stimulus 308. In a variant of the invention, the anodic stimulation 302 is performed at a sub-threshold maximum amplitude. In another variation of the invention, the anodic stimulus 302 is less than 3 volts. In yet another variation of the present invention, the duration of the anodic stimulus 302 is about 2-8 milliseconds. In yet another variation of the present invention, the cathodic stimulation 308 is brief. In yet another variation of the present invention, the cathodic stimulus 308 is about 0.3-0.8 milliseconds. In yet another variant of the invention, the cathode stimulus 3
08 is a high amplitude. In another variation of the present invention, the cathode stimulus 308 is in the range of about 3-20 volts. In yet another variation of the invention, the duration of the cathodic stimulation 308 is less than 0.3 millisecond and the voltage is greater than 20 volts.
In another variation, the anodic stimulus 302 is provided for more than 200 milliseconds after the heart beat. In the manner illustrated in these examples, and by virtue of the changes and modifications which will become apparent upon reading the present specification, a maximum membrane potential without activation is achieved in the first phase of the stimulation.

FIG. 4 illustrates another embodiment of the present invention in which a first stimulus phase, including anodal stimulus 402, is applied over time 404 with increasing intensity levels 406. The slope of the increasing intensity level 406 may be either linear or non-linear, and the slope may vary. Immediately after this anodic stimulus, a cathodic stimulus 40 of conventional intensity and duration
A second stimulus phase comprising 8 is provided. In a variation of the invention, the anodic stimulus 402 rises to a sub-threshold maximum amplitude.
In yet another variation of the present invention, the anodic stimulus 402 rises below a maximum amplitude of 3 volts. In another variation of the present invention, the anodic stimulus 402 has a duration of about 2-8 milliseconds. In yet another variation of the present invention, the cathodic stimulation 408 is brief. In another variant of the invention, the cathode stimulus 40
8 is about 0.3 to 0.8 milliseconds. In another variant of the invention, the amplitude is high. In another variation of the present invention, the cathode stimulus 408 is in the range of about 3-20 volts. In yet another variation of the present invention, the cathodic stimulus 408 is less than 0.3 milliseconds in duration, greater than 20 volts in voltage. In another variation, the anodic stimulus 402 is provided for more than 200 milliseconds after the heart beat. In the manner illustrated in these examples, and by virtue of the changes and modifications which will become apparent upon reading the specification, a maximum membrane potential without activation is achieved in the first phase of the stimulation.

FIG. 5 shows a two-phase electrical stimulus in which a first stimulus phase comprising a series of anodic pulses 502 is provided at an amplitude 504. In one variation, the dwell time 506 is the same duration as the stimulation time 508, and is given at baseline amplitude. In a variation, the dwell time 506 is a different duration than the stimulation period 508 and is given at the baseline amplitude. The pause time 506 is
Occurs after each stimulation time 508, except that a second stimulation phase, including conventional intensity and duration of the cathodic stimulation 510, is applied immediately after the series of anodizing pulses 502. In a variation of the invention, the sum of the mobile charges delivered by the series of anodic stimuli 502 is the sub-threshold maximum level. In yet another variation of the present invention, the first stimulation pulse of the series of anodic pulses 502 is provided for more than 200 milliseconds after the heart beat. In another variation of the present invention, cathodic stimulation 510 is provided in a short time. In yet another variant of the invention, the cathode stimulus 51
0 is about 0.3-0.8 milliseconds. In another variation of the present invention, the cathode stimulus 510 is of high amplitude. In yet another variation of the present invention, the anodic stimulation 510 is in the range of about 3-20 volts. In another variant of the invention, the cathode stimulus 5
10 has a duration of less than 0.3 milliseconds and a voltage greater than 20 volts.

Referring to FIG. 8, the method of operating a pacing device (pacemaker) disclosed herein is performed by a pacing device 10 having a structure and arrangement according to the prior art. A pacing device 10 embodying the present invention is implanted in the body of a patient 12 and housed in a sealed, physiologically inert outer can. The outer can body is itself conductive and therefore
Acts as an intermittent electrode in the pacing / sensing circuit of the pacing device. One or more pacing device leads (typically ventricle 14V and atria 14A) are electrically connected to pacing device 10 in a conventional manner and extend through vein 18 to the patient's heart. One or more exposed conducting electrodes receive a cardiac electrical signal; and / or
Alternatively, a pacing device lead 14A, 14V (typically near the distal end of the lead) is provided to deliver pacing electrical stimulation to the heart 16. As will be appreciated by those skilled in the art, conductors 14A, 1
The 4V is implanted into either the atria or ventricles of the heart 16 at their tips.

Referring to FIG. 9, the electronic circuit in the pacing device 10 according to the disclosed example of the present invention has a conventional structure and function. Therefore, it will be apparent to those skilled in the art that the structure and function of such a component have been determined, and will not be described in detail herein. For example, the pacing / control circuit 20 for carrying out the present invention includes a sense amplifier circuit 24, a pacing output circuit 26, a quartz clock 28, and a memory (random access memory (RAM) and read-only memory (ROM)). 30, central processing unit (C
PU) 32, and a telemetry circuit 34, all of which are well known. The CPU 32 executes a command programmed to give a pacing operation to the pacing output circuit 26 from the waveform stored in the RAM 30.

The wires 14A, 1A connected to the pacing device 10
The 4V extends between the implantation site of the adjustment device and the patient's heart 16 by implantation. Conductor 14A, 14V
Is directly or indirectly coupled to sense amplifier circuit 24 and pacing output circuit 26 as will be apparent to those skilled in the art. Thus, in a conventional manner, the electrical signal of the heart is sent to the sense amplifier circuit 24 and the pacing pulse is sent to the heart tissue via leads 14A, 14V.

The pacing device structure 10 preferably has internal telemetry (telemetry) circuitry so that it can be programmed (and potentially reprogrammed) using external programming and a control unit (not shown). 3
It is preferable to include the number 4. Suitable programmers and telemetry systems for use in practicing the present invention have been known for many years. Most commonly, telemetry systems for implantable medical devices use radio frequency (RF) transmitters and receivers and corresponding RF transmitters and receivers in external programming devices. Within the implantable device, the transmitter and receiver use wire coils as antennas to receive downlink telemetry signals and emit RF signals for uplink telemetry. This system is modeled as an air-core coupled transformer. The components of the pacing device 10 are supplied with power from a battery (not shown) in the sealed housing of the pacing device 10 according to the prior art.

<Example 1> The stimulation characteristics and the propagation characteristics of the myocardium were examined in isolated hearts using pulses of different polarity and phase. The experiments were performed with five isolated Langendorff rabbit perfused hearts. The epicardial conduction velocity was measured using a bipolar electrode array. The measurement was performed between 6 and 9 mm from the stimulation site. Transmembrane potentials were recorded using floating intracellular microelectrodes. Single-phase cathode pulse, single-phase anode pulse, advanced cathode two-phase pulse, and advanced anode 2
The protocol (plan) such as phase pulse was examined. Table 1 shows the conduction velocity across the fiber direction for each stimulation protocol when applying 3V, 4V and 5V stimuli with a pulse duration of 2 ms.

[0030]

[Table 1] Conduction velocity across the fiber direction (duration 2 ms) 3V 4V 5V Cathode single phase 18.9 ± 2.5cm / sec 21.4 ± 2.6cm / sec 23.3 ± 3.0cm / sec Anode single phase 24.0 ± 2.3cm / 27.5 ± 2.1cm / sec 31.3 ± 1.7cm / sec Advanced cathode 2 phase 27.1 ± 1.2cm / sec 28.2 ± 2.3cm / sec 27.5 ± 1.8cm / sec Advanced anode 2 phase 26.8 ± 2.1cm / sec 28.5 ± 0.7cm / sec Seconds 29.7 ± 1.8 cm / sec Table 2 shows the conduction velocity along the fiber direction for each stimulation protocol when applying 3V, 4V, and 5V stimuli with a pulse duration of 2 ms.

[0031]

[Table 2] Conduction velocity along fiber direction (2 ms stimulation) 3V 4V 5V Cathode single phase 45.3 ± 0.9cm / sec 47.4 ± 1.8cm / sec 49.7 ± 1.5cm / sec Anode single phase 48.1 ± 1.2cm / sec 51.8 ± 0.5cm / sec 54.9 ± 0.7cm / sec Advanced cathode 2 phase 50.8 ± 0.9cm / sec 52.6 ± 1.1cm / sec 52.8 ± 1.7cm / sec Advanced anode 2 phase 52.6 ± 2.5cm / sec 55.3 ± 1.5cm / sec 54.2 ± 2.3cm / sec

A significant difference was observed in the conduction velocities between the cathode single phase, anode single phase, advanced cathode 2 phase and advanced anode 2 phase (p <0.001). Maximum upstroke of action potential ((dV / dt) maximum) from transmembrane potential measurement
However, it was found that there was a sufficient correlation with the change in the conduction velocity in the longitudinal direction. With a 2 ms duration and a 4 volt pulse ((dV / dt) maximum), the cathode pulse is 63.
5 ± 2.4V / sec, anode pulse is 75.5 ± 5.6V /
Seconds.

Example 2 The effect of changing the pacing protocol on cardiac electrophysiology was analyzed using isolated hearts of Langendorff rabbits. The heart was stimulated with a constant voltage rectangular pulse. Protocols such as cathode single phase, anode single phase, advanced cathode 2 phase, and advanced anode 2 phase were investigated. The applied voltage was increased from 1 volt to 5 volts in 1 volt increments for both anode and cathode stimulation. The duration was increased from 2 ms to 10 ms in 2 ms increments. At a distance of 3 to 6 mm from the free wall of the left ventricle, the conduction velocity of the epicardium was measured in the case of following the fiber direction of the left atrium and the case of crossing it. FIG.
FIG. 7 shows the effect of stimulation pulse duration and stimulation protocol on conduction velocity.

FIG. 6 shows that 3 to 6 mm across the fiber direction.
Shows the speed measured between. In this region, at each pulse stimulation duration tested, cathodic monophasic stimulation 602
Showed the slowest conduction velocity. The next slowest was the anodic monophasic stimulus 604 and the advanced cathodic biphasic stimulus 606.
The fastest was the advanced anodic biphasic stimulation 608.

FIG. 7 shows the speed measured between 3 and 6 mm, parallel to the fiber direction. In this region, of the pulse stimulus durations tested, cathodic monophasic stimulation 702 exhibited the slowest conduction velocity. The measurement results of the velocities of the anodic monophasic stimulus 704 and the advanced anodic biphasic stimulus 706 were almost the same as those of the anodic monophasic stimulus which showed a slightly higher velocity. The fastest conducting velocity was the advanced anodic biphasic stimulus 708.

According to a first aspect of the present invention, electrical stimulation is provided to the myocardium. The anodically stimulating component of the biphasic electrical stimulation hyperpolarizes the tissue prior to stimulation, conducting a faster impact,
It releases more intracellular calcium, thereby increasing cardiac contractility so that superior cardiac contraction occurs. The cathodic stimulation component eliminates the disadvantages of anodal stimulation, so that effective cardiac stimulation can be provided at lower voltage levels than are required only for anodal stimulation. That, in turn, extends the life of the pacing device battery and reduces tissue damage.

According to a second aspect of the present invention, two-phase electrical stimulation is applied to the blood pool of the heart, ie, blood flowing toward and around the heart. Accordingly, heart stimulation can be performed without attaching a conductive wire in close contact with heart tissue.

According to a third aspect of the invention, biphasic electrical stimulation is applied to striated muscle tissue. The result of combining cathodic and anodic stimulation is that at lower voltage levels, more muscle motor units can be reduced, resulting in improved muscle response.

It will be readily apparent to those skilled in the art that, given the description of the basic concepts of the present invention, the foregoing detailed description has been presented by way of example only, and not limitation. Although not explicitly stated in the specification,
Various alterations, improvements and modifications will be apparent to those skilled in the art.
These modifications, changes and improvements are suggested herein and are within the spirit and scope of the invention. In addition, the pacing pulses described herein are well within the performance capabilities of existing pacing device electronics for proper programming. Accordingly, the invention is limited only by the following claims and equivalents thereof.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of advanced anode two-layer stimulation.

FIG. 2 is a schematic diagram of advanced cathode two-layer stimulation.

FIG. 3 is a schematic diagram of a low-level, long-time advanced anodic stimulation followed by conventional cathodic stimulation.

FIG. 4: Long-term advanced anodic stimulation at an inclined low level,
It is a schematic diagram of the subsequent conventional cathode stimulation.

FIG. 5 is a schematic diagram of a continuous, low-level, short-time advanced anodic stimulation followed by conventional cathodic stimulation.

FIG. 6 is a graph showing the relationship between conduction velocity across a fiber and pacing duration generated from a leading anode two-phase pulse.

FIG. 7 is a graph showing the relationship between the conduction velocity parallel to the fiber and the pacing duration generated from the advanced anode two-phase pulse.

FIG. 8 shows a pacing device of the present invention.

FIG. 9 shows an electronic circuit of the pacing device of the present invention.

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[Procedure amendment]

[Submission date] March 10, 2000 (200.3.1.1)
0)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

[0008] Nearly all artificial pacing uses a negative stimulus pulse, or in a bipolar system, the cathode is the distal pole and the anode is separated from the myocardium. In the example used in the anode current is disclosed in order to eliminate the residual charge on the electrodes, usually, that is used as a charge of minute strength. It does not affect the myocardium itself or affect its state. For such uses, see Herskovich's U.S. Pat.
No. 56.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

The method and apparatus of the present invention provide that each stimulus phase is
First, each with polarity, amplitude, shape and duration
And a second stimulus phase. Preferred embodimentMrNow, the first phase and
And the second phase have different polarities. One generationIn an alternative exampleIs 2
Different phase amplitudes. In a second alternative, the duration of the two phases
Are different. In a third alternative, the first phase is indicated by a cutting waveform
It is. In a fourth alternative, the amplitude of the first phase is ramped. No.
In a fifth alternative, the first phase stimulus is 200 ms after the heart beat
Added beyond. In a preferred alternative, the first phase stimulus is
Long duration anodic pulse with maximum amplitude below the value, second phase stimulation
Are cathode pulses of high amplitude and short time. Said feeIn an alternative example
Was noted that can be combined in various forms
No. Also, these alternatives are provided as examples only.
And should not be construed as limiting.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

FIG. 4 illustrates another embodiment of the present invention in which a first stimulus phase, including anodal stimulus 402, is applied over time 404 with increasing intensity levels 406. The slope of the increasing intensity level 406 may be either linear or non-linear, and the slope may vary. Immediately after this anodic stimulus, a cathodic stimulus 40 of conventional intensity and duration
A second stimulus phase comprising 8 is provided. In a variation of the invention, the anodic stimulus 402 rises to a sub-threshold maximum amplitude.
In yet another variation of the present invention, anodal stimulation 402 rises to less than the maximum amplitude 3 volts. In another variation of the present invention, the anodic stimulus 402 has a duration of about 2-8 milliseconds. In yet another variation of the present invention, the cathodic stimulation 408 is brief. In another variant of the invention, the cathode stimulus 40
8 is about 0.3 to 0.8 milliseconds. In another variant of the invention, the amplitude is high. In another variation of the present invention, the cathode stimulus 408 is in the range of about 3-20 volts. In yet another variation of the present invention, the cathodic stimulus 408 is less than 0.3 milliseconds in duration, greater than 20 volts in voltage. In another variation, the anodic stimulus 402 is provided for more than 200 milliseconds after the heart beat. In the manner illustrated in these examples, and by virtue of the changes and modifications which will become apparent upon reading the specification, a maximum membrane potential without activation is achieved in the first phase of the stimulation.

Claims (23)

[Claims] 1. A two-phase electrical cardiac pacing device, comprising: a first phase polarity, a first phase amplitude, a first phase shape and a first phase duration for preconditioning the myocardium for receiving post-stimulation. Means for defining a first stimulus phase having, a second stimulus phase having a polarity opposite to the first phase polarity, a second phase amplitude having an absolute value greater than the first phase amplitude, a second phase shape and A two-phase electrical cardiac pacing device comprising: means for defining a second phase duration; and means for sequentially applying a first stimulation phase and a second stimulation phase to heart tissue. 2. The cardiac pacing device of claim 1, wherein the first phase polarity is positive. 3. The two-phase cardiac pacing device of claim 1, wherein the first phase amplitude slopes from a baseline value to a second value. 4. The two-phase electric heart pacing device according to claim 3, wherein the second value is a value at the time of maximum amplitude below a threshold. 5. The two-phase cardiac pacing device of claim 4, wherein said sub-threshold maximum amplitude is about 0.5-3.5 volts. 6. The two-phase cardiac pacing device of claim 3, wherein the first phase duration is at least as long as the second phase duration. 7. The two-phase cardiac pacing device of claim 3, wherein the first phase duration is about 1 to 9 milliseconds. 8. The two-phase electrical cardiac pacing device of claim 3, wherein said second phase duration is about 0.2-0.9 milliseconds. 9. The two-phase cardiac pacing device of claim 3, wherein the second phase amplitude is about 2 to 20 volts. 10. The two-phase electrical heart pacing device of claim 3, wherein the second phase duration is less than 0.3 milliseconds and the second phase amplitude is greater than 20 volts. Pacing device. 11. The two-phase electrical cardiac pacing device according to claim 1, wherein the first stimulation phase has a predetermined amplitude,
2 further comprising a series of stimulation pulses of polarity and duration
Phase electric heart pacing device. 12. The two-phase electrical pacing device of claim 11, wherein the first stimulation phase further comprises a series of rest periods. 13. The two-phase electrical cardiac pacing device of claim 12, wherein the means for applying the first stimulus phase includes adding a rest period of baseline amplitude after at least one stimulus pulse. A two-phase electric heart pacing device further comprising: 14. The two-phase electrical pacing device of claim 13, wherein the rest period has a duration equal to the duration of a stimulation pulse. 15. The two-phase cardiac pacing device of claim 1, wherein the first phase amplitude is a sub-threshold maximum amplitude. 16. The two-phase electrical cardiac pacing device according to claim 15, wherein said sub-threshold maximum amplitude is about 0.5-3.
5 volt two-phase electrical heart pacing device. 17. The two-phase cardiac pacing device of claim 1, wherein the first phase duration is at least as long as the second phase duration. 18. The two-phase electrical cardiac pacing device of claim 1, wherein the first phase duration is about 1 to 9 milliseconds. 19. The two-phase cardiac pacing device of claim 1, wherein the second phase duration is about 1 to 9 milliseconds. 20. The two-phase cardiac pacing device of claim 1, wherein the second phase amplitude is about 2 to 20 volts. 21. The two-phase electrical cardiac pacing device of claim 1, wherein the second phase duration is less than 0.3 millisecond and the second phase amplitude is greater than 20 volts. Heart pacing device. 22. The two-phase electrical cardiac pacing device of claim 1, wherein the first stimulation phase is initiated more than 200 milliseconds after the completion of one cardiac cycle. . 23. A two-phase electrical cardiac pacing device, wherein the first stimulus phase has a positive polarity, a first phase amplitude, a first phase shape and a first phase duration, wherein the first phase amplitude Is about 0.5 ~
At 3.5 volts, the first phase duration is about 1 to 9 milliseconds, and the first stimulus phase predicts the myocardium, beginning more than 200 milliseconds after the completion of one cardiac cycle. Means for initiating the application of the first stimulus phase for adjusting; a second stimulus phase having a negative polarity, a second phase amplitude, a second phase shape and a second duration, wherein the second Means for initiating application of the second stimulus phase having a phase amplitude of about 4 to 20 volts and the second phase duration of about 0.2 to 0.9 milliseconds; Means for sequentially applying said second stimulation phase to heart tissue.