Abstract: A medical device system performs a method for determining presence of scar tissue through an implanted lead having an electrode for cardiac pacing and sensing. A sensing module senses heart activity with the electrode to produce a unipolar electrogram (EGM) waveform. A processor receives the unipolar EGM waveform and extracts two or more features representative of heart activity at the electrode. Scar tissue is identified at the site of the first electrode based upon at least two of the extracted features indicating scar tissue.

Abstract: A device includes a hemodynamic sensor measuring blood flow in the left chambers of a myocardium, at least one motion sensor measuring a displacement of the walls of the left ventricle of the myocardium, a first analysis module determining a time of closure of the aortic valve based on a signal of the hemodynamic sensor, a second analysis module determining a time of peak contraction of the left ventricle based on a signal from the motion sensors, and a third analysis module determining a time between the moment of peak contraction of the left ventricle and the moment of closure of the aortic valve. If the peak of contraction of the left ventricle is after the instant of closure of the aortic valve, the device adjusts the inter-ventricular delay and/or the atrioventricular delay to minimize or cancel the time disparity.

Abstract: A cardiac rhythm management system detects edema. In response to an episode of detected edema, it initiates or adjusts a cardiac resynchronization therapy and/or a cardiac contractility modulation (CCM) therapy.

Abstract: Methods, systems and devices described herein can be used for automatically adjusting one or more cardiac resynchronization therapy (CRT) pacing parameters (and more generally stimulation parameters), to achieve a long term reduction in left ventricular (LV) diastolic pressure (and more generally, preload) of a heart failure (HF) patient. A reduction in LV diastolic pressure is indicative of a reduction in preload (the force of blood the fills the left ventricle), which is typically indicative of an improvement in a patient's HF condition. In accordance with certain embodiments, when a set of stimulation parameters is tested, the set is tested for a period that is sufficiently long enough to allow the patient's compensatory mechanisms to react to the set of stimulation parameters and achieve a substantially steady-state LV diastolic pressure corresponding to the using the set of stimulation parameters.

Abstract: A microcurrent stimulation device with a power supply, two or more electrodes electronically coupled to the power supply, a microcontroller configured to generate an electromagnetic waveform, an impedance measurement module configured to measure electrical impedance of one or more biological tissues between the two or more electrodes. A first safety circuit monitors electric current flow through one or more components of the microcurrent stimulation device and interrupts electric current flow if the electric current flow through the one or more components is above a predetermined level. A second safety circuit interrupts electric current flow through the one or more components if a firmware failure occurs.

Abstract: Pacing related timing is determined for an implantable medical device (IMD) by pacing at an RV pacing site, a first LV pacing site and a second LV pacing site in accordance with a first site, a second site and a third site pacing order, and further in accordance with a first inter-electrode pacing delay between pacing at the first site and pacing at the second site and a second inter-electrode pacing delay between pacing at the second site and pacing at the third site. At least one of a sensed event or a paced event is detected for at each of the second site and the third site. The first inter-electrode pacing delay and the second inter-electrode pacing delay are adjusted to avoid sensed events in favor of paced events at each of the second site and the third site. An atrio-ventricular delay may also be adjusted to avoid sensed events or lack of capture due to possible fusion at the first site, in favor of paced events at the first site.

Abstract: A device for brain stimulation includes a lead body having a longitudinal surface and a distal end. The device further includes at least one ring array. The at least one ring array includes a plurality of split ring electrodes disposed on the distal end of the lead body. Each of the plurality of split ring electrodes includes a stimulating portion and a base portion coupled to the stimulating portion. The split ring electrodes of the at least one ring array are arranged about the circumference of the lead body. At least a portion of the base portion of at least one of the plurality of split ring electrodes is disposed below, and insulated from, at least a portion of the stimulating portion of another of the plurality of split electrodes.

Abstract: A cardiac rhythm management system selects one of multiple electrodes associated with a particular heart chamber based on a relative timing between detection of a depolarization fiducial point at the multiple electrodes, or based on a delay between detection of a depolarization fiducial point at the multiple electrodes and detection of a reference depolarization fiducial point at another electrode associated with the same or a different heart chamber. Subsequent contraction-evoking stimulation therapy is delivered from the selected electrode.

Abstract: Methods and/or devices for sampling a patient's intrinsic AV conduction time during cardiac therapy that may, e.g., change the AV delays to values based on the AV delays themselves, previously-sampled intrinsic AV conduction times, and/or one or more other parameters directly related to AV delays to provide a time period during which to measure the patient's intrinsic AV conduction time.

Abstract: A leadless implantable medical device (IMD) may include an electrode, a housing, and an energy transfer component. The housing retains a pulse generator configured to provide stimulation energy for delivery to a tissue of interest, a power supply, a memory storing programmable instructions, and a processor communicatively coupled to the memory. The processor is responsive to the programmable instructions to control operation of the leadless IMD. The electrode is securely affixed to the tissue of interest. The housing includes first and second body portions mated to one another at a detachable interface. The electrode is coupled to the second body portion. The energy transfer component is distributed between the first and second body portions and is configured to convey at least one of stimulation energy or sensed signals across the detachable interface when the first and second body portions are mated to one another.

Abstract: A system for use during revascularization includes a catheter having an adjustable balloon for delivery a stent, one or more pacing electrodes for delivering one or more pacing pulses to a patient's heart, and a pacemaker configured to generate the one or more pacing pulses to be delivered to the heart via the one or more pacing electrodes. The one or more pacing pulses are delivered at a rate substantially higher than the patient's intrinsic heart rate without being synchronized to the patient's intrinsic cardiac contractions, and are delivered before, during, or after an ischemic event to prevent or reduce cardiac injury.

Abstract: Techniques for minimizing interference between the first and second medical devices or between the different therapy modules of a common medical device are described herein. In some examples, a medical device may include shunt-current mitigation circuitry and/or at least one clamping structure that helps minimize or even eliminate shunt-current that feeds into a first therapy module of the medical device via one or more electrodes electrically connected to the first therapy module. The shunt-current may be generated by the delivery of electrical stimulation by a second therapy module. The second therapy module may be enclosed in a common housing with the first therapy module or may be separate, e.g., a part of a separate medical device.

Abstract: A rules engine acquires sensor data from sensors applied to the heart and determines whether an electrical waveform should be applied to the heart and, if so, the type of electrical waveform. A multi-phase cardiac stimulus generator generates waveforms in response to the rules engine from waveform data stored in a memory. The electrical waveform is applied to one or more electrodes implanted in or on the heart.

Abstract: A method can include providing (302) at least one parameter to control a therapy that is applied to at least one internal anatomical structure of a patient. Electrical data can be obtained from the patient (304), including electrical data acquired via a plurality of sensors during each of a plurality of iterations of the therapy. The electrical data can be analyzed (306) for a respective value of the at least one parameter of the therapy at each of the plurality of iterations of the applied therapy to compute an indication of at least one function of the at least one internal anatomical structure of the patient at each respective iteration of the applied therapy. The computed indication can be stored in memory (308). At least one parameter of the therapy can be adjusted (310) for delivery in a subsequent one of the plurality of iterations based on the indication of the at least one function.

Abstract: Various system embodiments comprise circuitry to determine when an arrhythmia has terminated, and a neural stimulator adapted to temporarily deliver neural stimulation therapy to assist with recovering from the arrhythmia in response to termination of the arrhythmia.

Abstract: Pacemaker for the stimulation of the human heart having three electrodes or two electrodes, with the first electrode connected to the right atrium, the second electrode connected to the right ventricle and the third electrode connected to the said right ventricle. The pacemaker is programmed so that there is first stimulation of the right atrium by means of the first electrode, then there is second stimulation of the right ventricle by means of the second electrode with an interval function of the programmed AV delay (50-400 msec) and with a voltage not exceeding 80-90% of the threshold potential, and finally there is third stimulation, again of the right ventricle by means of the third electrode with a voltage that conforms with Safety Margin rules and at a second stimulation time interval comprised between 50 msec and 300 msec.

Abstract: A device for detecting cardiac ischemia is disclosed. The device includes a processor that is configured to distinguish between two different heart beats types such as ventricularly paced beats and supraventricular beats. The processor collects separate reference data for a first one of the beat types indicative of the normal values of a cardiac feature. The processor performs an ischemia test to beats of the first type by first checking whether valid reference data exists for that beat type. If so, the ischemia test is based on this reference data. If no valid reference data exists for the firs beat type, the processor applies an ischemia test that is not based on reference data for the first beat type.

Abstract: In a pacing mode where the left ventricle is paced upon expiration of an escape interval that is reset by a right ventricular sense, there is the risk that the left ventricular pace may be delivered in the so-called vulnerable period that occurs after a depolarization and trigger an arrhythmia. To reduce this risk, a left ventricular protective period (LVPP) may be provided. Methods and devices for implementing an LVPP in the context of multi-site left ventricular pacing are described.

Abstract: A device comprises a cardiac contraction sensing circuit, a timer circuit, an electrical stimulation circuit, and a controller. The timer circuit provides a time duration of an atrial-atrial interval between successive atrial contractions, a ventricular-ventricular interval between successive ventricular contractions, and an atrial-ventricular (A-V) interval between an atrial contraction and a same cardiac cycle ventricular contraction. The controller includes an event detection module and a pacing module. The event detection module is configured for determining whether A-V block events are sustained over multiple cardiac cycles. The pacing module is configured for providing pacing therapy according to a primary pacing mode that includes AAI(R) mode with non-tracking VVI backup mode, and for switching the pacing therapy to a secondary tracking pacing mode if A-V block events are sustained over multiple cardiac cycles.

Abstract: A medical electrical lead includes an inductance augmenter assembly. The assembly includes an inductor coil formed of an insulated wire, which is wound about a non-conductive core and is electrically coupled in series between a conductor coil of the lead and an electrode of the lead.

Abstract: Systems and methods for monitoring and performing tissue modulation are disclosed. An example system may include an elongate shaft having a distal end region and a proximal end and having at least one modulation element and one sensing electrode disposed adjacent to the distal end region. The sensing electrode may be used to determine and monitor changes in tissue adjacent to the modulation element.

Abstract: An apparatus and method is described to sense sparse signals from a medical device using compressed sensing and then transmitting the data for processing in the cloud.

Abstract: Electrode structures for transvascular nerve stimulation combine electrodes with an electrically-insulating backing layer. The backing layer increases the electrical impedance of electrical paths through blood in a lumen of a blood vessel and consequently increases the flow of electrical current through surrounding tissues. The electrode structures may be applied to stimulate nerves such as the phrenic, vagus, trigeminal, obturator or other nerves.

Abstract: A pulse oximetry system for reducing the risk of electric shock to a medical patient can include physiological sensors, at least one of which has a light emitter that can impinge light on body tissue of a living patient and a detector responsive to the light after attenuation by the body tissue. The detector can generate a signal indicative of a physiological characteristic of the living patient. The pulse oximetry system may also include a splitter cable that can connect the physiological sensors to a physiological monitor. The splitter cable may have a plurality of cable sections each including one or more electrical conductors that can interface with one of the physiological sensors. One or more decoupling circuits may be disposed in the splitter cable, which can be in communication with selected ones of the electrical conductors. The one or more decoupling circuits can electrically decouple the physiological sensors.

Abstract: A system including a plurality of wireless sensors for monitoring one or more parameters of a subject is provided. The wireless sensors can be attachable to or implantable in the subject and form a network. The sensors can include a sensing component configured to detect a signal corresponding to at least one condition of the subject. The sensors further can include a communication component configured to wirelessly transmit the detected signal to at least another of the plurality of wireless sensors, and wirelessly receive a signal transmitted from at least one of the remaining sensors in the network.

Abstract: A method of stimulation therapy and an apparatus for providing the therapy which addresses cardiac dysfunction including heart failure. The therapy employs atrial pacing pulses delivered to a heart after the atrial refractory period and timed so that they will not cause a ventricular contraction. These atrial pacing are timed to achieve beneficial effects on myocardial mechanics (efficacy) while maintaining an extremely low level of risk of arrhythmia induction. These methods may be employed individually or in combinations in an external or implantable ESS therapy delivery device.

Abstract: Disclosed are compositions, methods and systems for preventing or treating cardiac dysfunction, particularly cardiac pacing dysfunction by genetic modification of cells of targeted regions of the cardiac conduction system. In particular, a bio-pacemaker composition is delivered to cardiac cells to increase the intrinsic pacemaking rate of the cells, wherein the bio-pacemaker composition increases expression of a channel or subunit thereof that produces funny current and a T-type Ca2+ channel or subunit thereof, and expresses one or more molecules that suppresses the expression of the wild type potassium channel.

Abstract: An artificial heart with a centrifugal pump is disclosed. In one embodiment, the artificial heart includes an impeller disposed in a housing. The impeller is configured to rotate to circulate blood through the housing. The impeller may include a set of blades on a first side of the impeller and a set of vanes on a second side opposite the first. The blades on the first side and the vanes on the second side allow blood circulation from both the first and the second sides of the impeller. The artificial heart may also or instead include a diffuser with adjustable vanes that enable variation in the output characteristics of the artificial heart pump. Various other artificial hearts, pumps, systems, and methods, including control systems and methods, are also disclosed.

Abstract: Exemplary methods are described for providing responsive vascular control with or without cardiac pacing. An implantable device with responsive vascular and cardiac controllers interprets physiological conditions and responds with an appropriate degree of vascular therapy applied as electrical pulses to a sympathetic nerve. In one implementation, an implantable device is programmed to deliver the vascular therapy in response to low blood pressure or orthostatic hypotension. The device may stimulate the greater splanchnic nerve, to effect therapeutic vasoconstriction. The vascular therapy is dynamically adjusted as the condition improves. In one implementation to benefit impaired physical mobility, vascular therapy comprises vasoconstriction and is timed to coincide with a recurring segment of the cardiac cycle. The vasoconstriction assists circulation and venous return in the lower limbs of inactive and bedridden individuals.

Abstract: In an example, a pacing therapy can be optimized using information indicative of an offset duration between an intrinsic first atrioventricular delay of a subject at rest and a second atrioventricular delay specified to enhance a cardiac output of the subject heart when the subject is at rest. Optimizing the therapy can include receiving information about a heart rate of the subject and receiving information about an intrinsic, heart rate dependent atrioventricular delay. In an example, a therapy parameter, such as a therapy atrioventricular delay, can be adjusted using information about the received heart rate of the subject, the heart-rate-dependent third AV delay, or the offset duration.

Abstract: According to some embodiments, a method for improving functional recovery after cerebro-vascular accidents, such as strokes, in humans and animals comprises stimulating a cranial nerve with electrical current. According to some embodiments, a method for improving functional recovery after stroke in a human or animal in need thereof comprises applying to the cranial nerve of the human or animal a stimulating electrical signal that causes neurophysiological, morphological, chemical, or neuronal connective alteration in the brain, where the alteration changes neural function in the brain so as to change functional recovery and functional dynamics in the human or animal. According to some embodiments, a method for improving functional recovery after stroke in a human or animal in need thereof comprises applying to a first cranial nerve a first stimulating electrical signal optimized so as to promote stroke recovery.

Abstract: The present invention relates in general to methodologies for the treatment quenching preconditioning and communication between the intrinsic cardiac nervous system and an electrical stimulus. In particular, the present invention utilizes spinal cord stimulation to alter and/or affect the intrinsic cardiac nervous system and thereby protect the myocytes, stabilize myocardial electrical instability and/or alleviate or diminish cardiac pathologies.

Abstract: According to various method embodiments, a person is indicated for a therapy to treat a cardiovascular disease, and the therapy is delivered to the person to treat the cardiovascular disease. Delivering the therapy includes delivering a vagal stimulation therapy (VST) to a vagus nerve of the person at a therapeutically-effective intensity for the cardiovascular disease that is below an upper boundary at which upper boundary the VST would lower an intrinsic heart rate during the VST.

Abstract: A method and apparatus for selection of one or more ventricular chambers to stimulate for ventricular resynchronization therapy. Intrinsic intracardia electrograms that include QRS complexes, are recorded from a left and right ventricle. A timing relationship between the intrinsic intracardia electrograms recorded from the left and right ventricle is then determined. In one embodiment, the timing relationship is determined using a delay between a left ventricular and a right ventricular sensed intrinsic ventricular depolarizations and a duration interval of one or more QRS complexes. In one embodiment, the duration of QRS complexes is determined from either intracardiac electrograms or from surface ECG recordings. One or more ventricular chambers in which to provide pacing pulses are then selected based on the timing relationship between intrinsic intracardia electrograms recorded from the right and left ventricle, and the duration of one or more QRS complexes.

Abstract: A method of fabricating electrical feedthroughs selectively removes substrate material from a first side of an electrically conductive substrate (e.g. a bio-compatible metal) to form an array of electrically conductive posts in a substrate cavity. An electrically insulating material (e.g. a bio-compatible sealing glass) is then flowed to fill the substrate cavity and surround each post, and solidified. The solidified insulating material is then exposed from an opposite second side of the substrate so that each post is electrically isolated from each other as well as the bulk substrate. In this manner a hermetic electrically conductive feedthrough construction is formed having an array of electrical feedthroughs extending between the first and second sides of the substrate from which it was formed.

Abstract: Described herein are implantable systems and devices, and methods for use therewith, that can be used to perform arrhythmia discrimination based on activation times. A plurality of different sensing vectors are used to obtain a plurality of IEGMs that collectively enable electrical activations to be detected in the left atrial (LA) chamber, the right atrial (RA) chamber, and at least one ventricular chamber of a patient's heart. For each of a plurality of cardiac cycles, there is a determination, based on the plurality of obtained IEGMs, of an LA activation time, an RA activation time, and a ventricular activation time. Arrhythmia discrimination is then performed based on the determined activation times.

Abstract: A method for use with an implantable system including a lead having multiple electrodes implantable proximate to a patient's left ventricular (LV) chamber includes simultaneously delivering pacing pulses over corresponding pacing vectors defined by electrodes proximate to the LV chamber. The method includes recording evoked responses responsive to the pacing pulses that are measured over separate corresponding sensing channels. The method also includes comparing the evoked responses to a template that represents local capture of a local LV tissue region along one or more of the corresponding pacing vectors. The comparison is used to determine whether the pacing pulses achieved local capture along the corresponding pacing vectors. At least one of the pacing pulses or pacing vectors are updated based on the comparison of the evoked responses to the template in order to determine a local capture threshold for the corresponding pacing vectors.

Abstract: One or more temporal stimulation parameters of vagus nerve stimulation (VNS) are selected to substantially modulate one or more target physiological functions without substantially modulating one or more non-target physiological functions. In one embodiment, a stimulation duty cycle is selected such that VNS is delivered to the cervical vagus nerve trunk to modulate a cardiovascular function without causing laryngeal muscle contractions.

Abstract: Devices, systems, and methods for treating a heart of a patient may make use of structures which limit a size of a chamber of the heart, such as by deploying a tensile member to bring a wall of the heart toward (optionally into contact with) a septum of the heart. The implant may include an electrode or other structure for applying pacing signals to one or both ventricles of the heart, for defibrillating the heart, for sensing beating of the heart or the like. A wireless telemetry and control system may allowing the implant to treat congestive heart failure, monitor the results of the treatment, and apply appropriate electrical stimulation.

Abstract: Methods and devices for determining optimal Atrial to Ventricular (AV) pacing intervals and Ventricular to Ventricular (VV) delay intervals in order to optimize cardiac output. Impedance, preferably sub-threshold impedance, is measured across the heart at selected cardiac cycle times as a measure of chamber expansion or contraction. One embodiment measures impedance over a long AV interval to obtain the minimum impedance, indicative of maximum ventricular expansion, in order to set the AV interval. Another embodiment measures impedance change over a cycle and varies the AV pace interval in a binary search to converge on the AV interval causing maximum impedance change indicative of maximum ventricular output. Another method varies the right ventricle to left ventricle (VV) interval to converge on an impedance maximum indicative of minimum cardiac volume at end systole. Another embodiment varies the VV interval to maximize impedance change.

Abstract: Methods and devices for cardiac signal analysis in implantable cardiac therapy systems. Several signal processing and/or conditioning methods are shown including R-wave detection embodiments including the use of thresholds related to previous peak amplitudes. Also, some embodiments include sample thresholding to remove extraneous data from sampled signals. Some embodiments include weighting certain samples more heavily than other samples within a sampled cardiac signal for analysis.

Abstract: A device and method for delivering high-energy electrical stimulation to the heart in order to improve cardiac function in heart failure patients. The high-energy stimulation mimics the effects of exercise and improves symptoms even in patients who are exercise intolerant. The high-energy stimulation may be delivered on an intermittent basis either as pacing pulses in accordance with a programmed pacing mode and with a higher pacing pulse energy than used for conventional pacing or as low energy shock pulses.

Abstract: Described herein are implantable cardiac stimulation devices, and methods for use therewith. A pacing channel of such a device includes a pace output terminal, a pulse generator and at least two pace return electrode terminals. The pace output terminal is coupleable to an electrode for use as an anode. The pulse generator is configured to selectively output an electrical stimulation pulse to the pace output terminal. Each of the pace return electrode terminals is coupleable to a separate one of at least two further electrodes for use as a cathode. Switching circuitry selectively couples any one of the pace return electrode terminals of the pacing channel to the pace return capacitor of the pacing channel at a time, thereby enabling the pace return capacitor to be shared by at least two of the pace return electrode terminals of the pacing channel. Additional embodiments are also disclosed herein.

Abstract: An electric stimulator for heart, brain, organs and general cells with a possibly random shape and position of electrodes which enhances its performance for breaking the symmetry. Two types of electrodes are introduced: type-1, or active electrodes are similar to prior art, while type-2, or passive electrodes have not been used in this context. Passive electrodes are electrically insulated, being unable to inject current in the surrounding medium, but they are capable of shaping the electric field, which has consequence on the path of the stimulating currents injected by type-1 electrodes. The invention also discloses a supercapacitor-type passive electrode of type-2, which maximizes the stored charge on the electrode—therefore increasing the electric field magnitude created by it.

Abstract: According to one aspect, various methods and apparatus are used for treating a condition of a patient's heart, and for monitoring cardiac operation. In one approach consistent therewith, an electrode arrangement is placed in a right ventricle of the heart. The electrode arrangement is used to capture the myocardium for re-synchronization of the left and right ventricles by providing first and second signal components having opposite polarity on respective electrodes. The electrode arrangement is connected to an implantable CRM device that has the capability of pacing/sensing atrium, pacing/sensing ventricles, and deliver defibrillation therapy from the right side of the heart. The CRM device captures ventricular contractions to treat conduction abnormalities in one or more of the ventricles.

Abstract: A method discriminates between ventricular arrhythmia and supraventricular arrhythmia by determining the direction of an electrical signal conducted through the atrioventricular node. An implantable cardiac defibrillator provides atrioventricular and ventriculoatrial pacing bursts to determine if an arrhythmia with a 1:1 atrial to ventricular relationship is due to ventricular tachycardia or supraventricular tachycardia. This discrimination capability reduces the incidence of inappropriate shocks from dual-chamber implantable cardiac defibrillators to near zero and provides a method to differentially diagnose supraventricular tachycardia from ventricular tachycardia.

Abstract: Various aspects of the present subject matter relate to a method. According to various method embodiments, cardiac activity is detected, and neural stimulation is synchronized with a reference event in the detected cardiac activity. Neural stimulation is titrated based on a detected response to the neural stimulation. Other aspects and embodiments are provided herein.

Abstract: Cardiac lead implantation systems, devices, and methods for lead implantation are disclosed. An illustrative cardiac lead implantation system comprises a mapping guidewire including one or more electrodes configured for sensing cardiac electrical activity, a signal analyzer including an analysis module configured for analyzing an electrocardiogram signal sensed by the mapping guidewire, and a user interface configured for monitoring one or more hemodynamic parameters within the body. The sensed electrical activity signal can be used by the analysis module to compute a timing interval associated with ventricular depolarization.

Abstract: An implantable medical device includes a sensor configured to generate an endocardial acceleration (EA) signal representative of activity of a patient's heart. The device further includes one or more circuits configured to identify within the EA signal at least one EA signal component corresponding to at least one peak of endocardial acceleration, and extract from the at least one EA signal component at least two characteristic parameters. The one or more circuits are further configured to generate a composite index based on a combination of the at least two characteristic parameters, determine a plurality of values of the composite index for a plurality of pacing configurations, and select a current pacing configuration from among the plurality of pacing configurations based on the plurality of values of the composite index.

Abstract: An implantable medical system that includes a cardiac therapy module and a neurostimulation therapy module may identify when neurostimulation electrodes have migrated toward a patient's heart. In some examples, the system may determine whether the neurostimulation electrodes have migrated toward the patient's heart based on a physiological response to an electrical signal delivered to the patient via the neurostimulation electrodes. In addition, in some examples, the system may determine whether the neurostimulation electrodes have migrated toward the patient's heart based on an electrical cardiac signal sensed via the neurostimulation electrodes.