System for multiple site biphasic stimulation to revert ventricular arrhythmias
First Claim
1. An apparatus for applying biphasic myocardial stimulation, the apparatus comprising:
- at least two electrodes adapted to administer biphasic stimulation to myocardial tissue; and
a pacemaker connected to provide biphasic stimulation to the at least two electrodes, wherein the biphasic stimulation comprises;
a first stimulation phase having a first phase polarity, a first phase amplitude, a first phase shape, and a first phase duration, so as to precondition the myocardium to accept subsequent stimulation, and a second stimulation phase having a second phase polarity, a second phase amplitude that is larder in absolute value than the first phase amplitude, a second phase shape, and a second phase duration; and
wherein the pacemaker repeatedly provides biphasic stimulation so long as fibrillation is detected.
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Accused Products
Abstract
An anti-reentry apparatus and method for reverting ventricular arrhythmias. Biphasic stimulation is applied at multiple ventricular sites to revert arrhythmias caused by reentry, particularly multiple random reentry. In the preferred embodiment, the first phase of biphasic stimulation is anodal, and is at a maximum subthreshold amplitude. The anodal phase preconditions the myocardium to accept the second phase (cathodal) such that less electrical energy is required to reach the threshold amplitude to produce depolarization. The anodal phase stimulation may have a shape over time that is square wave, ramped, or a series of short square wave pulses. Multiple electrodes located at multiple ventricular sites may be stimulated simultaneously, or they may be sequentially stimulated over time in a manner mimicking the normal progress pattern of cardiac depolarization. The multiple ventricular electrodes may stimulate from internal or external surfaces. One or both ventricles may receive biphasic stimulation from multiple electrodes. The invention also may be practiced with respect to atria.
234 Citations
22 Claims
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1. An apparatus for applying biphasic myocardial stimulation, the apparatus comprising:
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at least two electrodes adapted to administer biphasic stimulation to myocardial tissue; and
a pacemaker connected to provide biphasic stimulation to the at least two electrodes, wherein the biphasic stimulation comprises;
a first stimulation phase having a first phase polarity, a first phase amplitude, a first phase shape, and a first phase duration, so as to precondition the myocardium to accept subsequent stimulation, and a second stimulation phase having a second phase polarity, a second phase amplitude that is larder in absolute value than the first phase amplitude, a second phase shape, and a second phase duration; and
wherein the pacemaker repeatedly provides biphasic stimulation so long as fibrillation is detected. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
wherein the electrodes closest to the A-V node are the first to administer stimulation, wherein the electrodes farthest from the A-V node, following the normal intrinsic conduction paths, are the last to administer stimulation; - and
wherein the electrodes intermediate between the electrodes closest to the A-V node and the electrodes farthest from the A-V node each administer stimulation at an intermediate time that is proportional to their intermediate position, following the normal intrinsic conduction paths.
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19. The apparatus for applying myocardial stimulation according to claim 18, wherein the electrodes are ordered by class according to their distance from the A-V node, following the normal intrinsic conduction paths.
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20. The apparatus for applying myocardial stimulation according to claim 19, wherein the number of classes is between two and about thirty.
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21. The apparatus for applying myocardial stimulation according to claim 1, wherein the first stimulation phase comprises an anodal stimulus.
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22. A cardiac stimulation apparatus for reverting ventricular arrhythmias with biphasic waveforms, the apparatus comprising:
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at least two electrodes adapted to administer biphasic stimulation to cardiac tissue, wherein the biphasic stimulation comprises;
a first stimulation phase having a positive polarity, a subthreshold amplitude, a duration of about one millisecond to about nine milliseconds, and a shape, wherein the shape is selected from the group consisting of;
square wave pulse, ramped pulse, and series of short duration square wave pulses; and
a second stimulation phase having a negative polarity, an amplitude of about two volts to about twenty volts that is larger in absolute value than the first stimulation chase subthreshold amplitude, and a duration of about 0.2 millisecond to about 1.5 milliseconds.
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Specification