Abstract: A cardiac medical device and associated method control delivery of dual chamber burst pacing pulses in response to detecting tachycardia. In one embodiment, a single chamber pacing pulse is delivered in response to detecting a tachycardia. Dual chamber pacing pulses are delivered subsequent to the single chamber pacing pulse. An intrinsic depolarization is sensed subsequent to delivering the dual chamber pacing pulses. The tachycardia episode is classified in response to the sensed intrinsic depolarization.

Abstract: A band stop filter is provided for a lead wire of an active medical device (AMD). The band stop filter includes a capacitor in parallel with an inductor. The parallel capacitor and inductor are placed in series with the lead wire of the AMD, wherein values of capacitance and inductance are selected such that the band stop filter is resonant at a selected frequency. The Q of the inductor may be relatively maximized and the Q of the capacitor may be relatively minimized to reduce the overall Q of the band stop filter to attenuate current flow through the lead wire along a range of selected frequencies. In a preferred form, the band stop filter is integrated into a TIP and/or RING electrode for an active implantable medical device.

Abstract: An electrode for interventional purposes, such as a cardiac pacemaker, neurostimulation, or ICD electrode, comprises an elongate electrode body (6), at least one electrode pole (5) in the area of the distal end (4) of the electrode body (6) for delivering an intervention pulse, at least one supply line (7) running in the electrode body (6) to the at least one electrode pole (5), and an electrode sheath (8) for insulating the supply line (7). The first and/or second material is produced in such a way that it contains conductive particles embedded in a polymer matrix in a concentration which is greater than or equal to the percolation threshold.

Abstract: An apparatus comprises an implantable sensor and a signal analyzer circuit communicatively coupled to the implantable sensor. The implantable sensor is configured for coupling to an implantable lead and the implantable sensor provides an electrical vibration sensor signal representative of mechanical vibration of the implantable lead. The signal analyzer circuit is configured to determine a baseline of the vibration sensor signal, detect a change in the vibration sensor signal from the baseline vibration sensor signal, and provide an indication of the change to a user or process.

Abstract: Systems and methods are provided for reducing heating within pacing/sensing leads of a pacemaker or implantable cardioverter-defibrillator that occurs due to induced radio frequency (RF) currents during a magnetic resonance imaging (MRI) procedure, or in the presence of other sources of strong RF fields. For example, bipolar coaxial leads are described wherein the ring conductor of the lead is disconnected from the ring electrode via a switch in response to detection of MRI fields to convert the ring conductor into an RF shield for shielding the inner tip conductor of the lead so as to reduce the strength of RF currents induced therein and hence reduce tip heating. Other exemplary leads are described wherein a band stop filter is instead used to block RF signals to likewise convert the ring conductor into an RF shield. The switches and band stop filters also help to prevent MRI-induced stimulation.

Abstract: This disclosure describes implantable medical leads that include a lead body and an electrode. A width of the electrode as measured along a longitudinal direction of the lead varies about the perimeter of the lead. The uneven width of the electrode may bias a stimulation field in a particular direction, e.g., a radial or transverse direction relative to the longitudinal axis of the lead. Electrodes with an uneven width may be useful for controlling the direction of propagation of the stimulation field in order to, for example, avoid phrenic nerve stimulation during LV pacing or neck muscle stimulation during vagal neurostimulation.

Abstract: Methods and devices for implanting pacing electrodes or other apparatus, or for delivering substances, to the heart of other tissues within the body. A guided tissue penetrating catheter is inserted into a body lumen (e.g., blood vessel) or into a body cavity or space (e.g., the pericardial space) and a penetrator is advanced from the catheter to a target location. In some embodiments, a substance or an apparatus (such as an electrode) may be delivered through a lumen in the penetrator. In other embodiments, a guidewire may be advanced through the penetrator, the penetrating catheter may then be removed and an apparatus (e.g., electrode) may then be advanced over that guidewire. Also disclosed are various implantable electrodes and electrode anchoring apparatus.

Abstract: Some embodiments of a cardiac stimulation system may include a plurality of electrode assemblies that are interconnected by one or more wires while at least one of the electrode assemblies (e.g., a control electrode) wirelessly receives energy through inductive coupling with a power communication unit external to the heart (e.g., a device implanted along one or more ribs). These embodiments may provide an arrangement for efficient inductive coupling from the power communication unit to the control electrode. Also, in some circumstances, the cardiac stimulation system may eliminate the need for wired leads that extend to a location outside the heart, thereby reducing the likelihood of infection that passes along the wire and into the heart.

Abstract: One embodiment of the present invention provides a lead electrode assembly for use with an implantable cardioverter-defibrillator subcutaneously implanted outside the ribcage between the third and twelfth ribs comprising the electrode.

Abstract: Methods for protecting biomaterials comprise attaching CD47 or Ig domain thereof to the surface of the biomaterial, thereby inhibiting or reducing immune cell attachment and/or immune cell-mediated damage to the biomaterial. Also provided are kits for practicing these methods and the protected biomaterials.

Abstract: An implanted electrical signal generator delivers a novel exogenous electrical signal to a vagus nerve of a patient. The vagus nerve conducts action potentials originating in the heart and lungs to various structures of the brain, thereby eliciting a vagal evoked potential in those structures. The exogenous electrical signal simulates and/or augments the endogenous afferent activity originating from the heart and/or lungs of the patient, thereby enhancing the vagal evoked potential in the various structures of the brain. The exogenous electrical signal includes a series of electrical pulses organized or patterned into a series of microbursts including 2 to 20 pulses each. No pulses are sent between the microbursts. Each of the microbursts may be synchronized with the QRS wave portion of an ECG. The enhanced vagal evoked potential in the various structures of the brain may be used to treat various medical conditions including epilepsy and depression.

Abstract: Techniques are provided for detecting heart failure or other medical conditions within a patient using an implantable medical device, such as pacemaker or implantable cardioverter/defibrillator, or external system. In one example, physiological signals, such as immittance-based signals, are sensed within the patient along a plurality of different vectors, and the amount of independent informational content among the physiological signals of the different vectors is determined. Heart failure is then detected by the implantable device based on a significant increase in the amount of independent informational content among the physiological signals. In response, therapy may be controlled, diagnostic information stored, and/or warning signals generated. In other examples, at least some of these functions are performed by an external system.

Abstract: A carrier for an ablation element is provided. The carrier includes a plurality of walls defining a receiving portion configured to receive at least a portion of an ablation element. A plurality of connection formations are disposed on an exterior surface of least one of the plurality of walls. Each of the plurality of connection formations is disposed at a different vertical position of the carrier. A device for epicardial ablation is also provided. The device includes a plurality of carriers disposed adjacent to each other. Each carrier includes a plurality of walls defining a receiving portion configured to receive at least a portion of an ablation element. A plurality of connection formations are disposed on an exterior surface of at least one of the plurality of walls of each carrier. Each of the plurality of connection formations is disposed at a different vertical position of a carrier.

Abstract: An implantable medical device, IMD, (100) is connectable to at least one ventricular lead (210) having a ventricular basal electrode (214) and a ventricular apical electrode (212). The IMD (100) comprises a pulse generator (120) for generating pacing pulses applied to a heart (10) through the ventricular lead (210). The operation of this pulse generator (120) is controlled by a controller (130) that is configured to control the pulse generator to first deliver a pacing pulse to the ventricular basal electrode (214) to stimulate the basal portion of the ventricle (12, 14) before a pacing pulse is delivered to the apical portion of the ventricle (12, 14) by the ventricular apical electrode (212). This pulse sequence achieves a biologically more correct cardiac stimulation and a contraction pattern that reduces the risk for valvular regurgitation.

Abstract: Various embodiments relating to MRI safe, multi-polar active fixation stimulation leads with co-radial construction are disclosed. Some embodiments, allow the use of the generally smaller diameter co-radially constructed body (coated wires) to construct an active fixation lead, with an extendable/retractable fixation mechanism. Some embodiments use a connector assembly with an inner terminal ring, a terminal pin partially rotatably positioned within the annular inner terminal ring, and one or more resilient C-clips disposed within circumferential recesses. The resilient C-clips mechanically and electrically couple the inner terminal ring and the terminal ring while substantially limiting relative longitudinal translation of the terminal pin.

Abstract: The present invention provides devices and methods for the treatment of atrial fibrillation. In one embodiment a deflectable sheath catheter includes an elongate catheter body having proximal and distal ends, the distal end having a distal tip region that includes a plurality of flexible segments with varying degrees of stiffness. A handle portion can be located at the proximal end of the catheter body to provide a steering mechanism that causes the distal tip region to deflect according to a compound curve.

Abstract: An implantable sensor is provided that includes a piezopolymer sensor element including a body having a plurality of layers of a piezopolymer, and an attachment device configured to hold the piezopolymer sensor element in direct contact with at least one of a bodily fluid and bodily tissue such that the piezopolymer sensor element is configured to bend in response to motion of the at least one of bodily fluid and bodily tissue. A pair of electrodes is attached to the piezopolymer sensor element and the electrodes are configured to collect an electrical charge that is generated within the piezopolymer sensor element due to the bending of the piezopolymer sensor element.

Abstract: Electrical crosstalk between two implantable medical devices or two different therapy modules of a common implantable medical device may be evaluated, and, in some examples, mitigated. In some examples, one of the implantable medical devices or therapy modules delivers electrical stimulation to a nonmyocardial tissue site or a nonvascular cardiac tissue site, and the other implantable medical device or therapy module delivers cardiac rhythm management therapy to a heart of the patient.

Abstract: A connector for an implantable medical lead that is electrically and mechanically connectable to an implantable medical device, has a connector pin made of a first conducting material. A tubular insulator made of an insulating material concentrically surrounds at least a portion of the pin. A connector ring made of a second conducting material is concentrically positioned around at least a portion of the insulator. The insulator is connected to the connector ring by spark plasma sintering in the case of an active fixation lead, and is connected to the ring and the pin by spark plasma sintering in the case of a passive fixation lead.

Abstract: A medical electrical lead that includes a lead body and at least one tubular electrode sub-assembly positioned over and attached to the external surface of the lead body. The lead body includes at least one elongated conductive element, such as a cable, that is electrically connected to a coiled electrode of the tubular electrode sub-assembly. The tubular electrode sub-assembly includes a tubular liner and an electrode embedded in the outer surface of the liner. In some embodiments, only a portion of the inner surface of the tubular liner is attached to the lead body which may potentially improve flexibility of the medical electrode lead in the area occupied by the tubular electrode sub-assembly.

Abstract: The invention relates to an intracardial implantable electrode line for connection to an implantable medical device, in particular a cardiac pacemaker or cardioverter/defibrillator or the like, which has an acceleration sensor in the area of its distal end, which is implemented to record and differentiate acceleration values in at least two different directions. The invention additionally relates to a cardiac stimulation configuration which also has a cardiac stimulator in addition to such an electrode line.

Abstract: A nerve stimulation electrode implantation system includes: an introduction portion that has a cylindrical main body which has an internal cavity, and an incision component which has a blunt dissection portion that bluntly dissects biological tissue, and which is formed so as to be transparent, and which is attached to a distal end portion of the main body; an observation portion that is inserted into the introduction portion such that it is able to observe the periphery of the incision component through the incision component; and a peeling portion that is positioned such that it is able to rotate around its own axis and is able to move relatively in this axial direction relative to the introduction portion, and that removes peripheral tissue from the periphery of the nerve tissue.

Abstract: This document discusses, among other things, a lead body extending longitudinally along a lead axis, a driver axially displaceable relative to the lead body, and a driven member coupled to the lead body and displaceable away from the lead axis. The driven member at least partially defines an expandable passage having at least one internal dimension. The driver is displaceable into the expandable passage and has at least one outer dimension that is larger than the at least one internal dimension of the expandable passage. An example method includes disposing a first member having a first cross-section in a lead assembly having a lead axis, an expandable passage, and a displaceable member proximate the expandable passage. The method further includes urging the first member into the expandable passage in the lead assembly, and urging the displaceable member away from the lead axis to expand the expandable passage.

Abstract: A method and apparatus for retaining a medical device within a blood vessel are described. A medical device (e.g. a pulse generator or a lead) is positioned within a blood vessel. An expandable the retention sleeve is passed into the vessel adjacent to the medical device and expanded to an expanded position to engage the medical device between an exterior surface of the retention sleeve and a surface of the vessel.

Abstract: Techniques are provided for detecting atrial events that might be hidden due to the operation of a post-ventricular atrial blanking (PVAB) interval or other atrial channel blanking interval. In one example, candidate atrial events are identified within signals occurring during the PVAB interval. Then, a determination is made as to whether the candidate atrial event is a true atrial event based on a comparison of characteristics of the candidate atrial event with characteristics of prior known atrial events within the patient. By comparing the characteristics of the “hidden” event with the characteristics of prior known atrial events within the patient, a quick and accurate determination can be made whether the event should be counted as a P-wave. In this manner, hidden atrial arrhythmias can be detected and mode switch oscillations can be reduced or eliminated.

Abstract: Embodiments of the present invention are directed to devices, systems and methods for pacing and sensing, in a chamber of a patient's heart, that provide for good sensed R wave amplitudes and capture thresholds, yet avoids extracardiac stimulation. Such benefits are achieved by using what is referred to herein as a “distributed” anode, where one portion of the anode is within 5 mm of the cathode, but another portion of the anode is at least 10 mm from the cathode. While especially useful for pacing and sensing in the left ventricle, embodiments of the present invention can be used to pace and sense in any chamber of the heart.

Abstract: The present invention relates to a medical device (2) for electrical stimulation. The device comprising an implantable elongated lead system (20) having a distal end (21) and a proximal end (22), the lead system comprises one or more electrical conductors (23) for connection to one or more electrodes (24). The one or more electrical conductors are wound along a length axis (25) of the lead system with a plurality of windings, and wherein the density of windings is non-uniformly distributed along the length axis. In an embodiment, the medical device is in the form of a deep brain stimulation (DBS) device.

Abstract: A medical device includes a sensor for sensing for an MRI gradient magnetic field and a microprocessor configured to operate in a signal processing mode in which electrical signals induced by the gradient magnetic field are not counted as cardiac events.

Abstract: A composite lead body includes a rigid polymer material, such as silicone-polyurethane co-polymers, in a proximal portion of the lead body and a flexible polymer material, such as silicone, in a distal portion of the lead body. The flexible polymer material is molded in-situ about the end of the rigid polymer material, which is pre-formed, forming a junction at which the two polymers are bonded together, preferably in an interdigitated manner. The end of the rigid polymer is treated with a primer in order to facilitate the formation of a strong bond between the polymers. The molding process, advantageously, provides substantial control over the final shape of the molded polymer, inhibiting the formation of discontinuities in the shape of the lead body.

Abstract: An esophageal mapping catheter enables a physician to map the location of the esophagus so as to avoid damaging the esophagus during radio frequency (RF) ablation procedures. Information from the esophageal mapping catheter is communicated to a patient information unit, communications unit and/or electroanatomic mapping system. The electroanatomic mapping system uses the information from the esophageal mapping catheter to develop a three-dimensional map of the esophagus and to monitor the temperature within the esophagus in order to prevent the creation of esophageal fistula.

Abstract: A cardiac stimulator has an implantable cardiac lead that carries a temperature sensitive element with a surface thereof in contact with biological matter. The temperature sensitive element emits a temperature signal corresponding to the temperature of biological matter, such as blood, in contact with the surface of the temperature sensitive element. Processing circuitry receives the temperature signal and determines a variability thereof within a selected time interval. A status signal is emitted dependent on this variability.

Abstract: A method and apparatus is described for detecting and localizing areas of myocardial infarction or ischemia. By pacing sites in proximity to the infarcted or ischemic region with appropriately timed pacing pulses, the region is pre-excited in a manner that lessens the mechanical stress to which it is subjected, thus reducing the metabolic demand of the region and the stimulus for remodeling.

Abstract: A medical electrical lead includes a canted lead body distal portion extending from an approximately straight lead body proximal portion; the canted distal portion includes an approximately straight segment and a hump-like segment extending from a first end, in proximity to the approximately straight segment, to a second end. The lead further includes a first electrode coupled to the approximately straight segment of the distal portion and a second electrode coupled to the distal portion in proximity to a second end of the hump-like segment.

Abstract: Various fixation techniques for implantable medical device (IMDs) are described. In one example, an assembly comprises an IMD; and a set of active fixation tines attached to the IMD. The active fixation tines in the set are deployable from a spring-loaded position in which distal ends of the active fixation tines point away from the IMD to a hooked position in which the active fixation tines bend back towards the IMD. The active fixation tines are configured to secure the IMD to a patient tissue when deployed while the distal ends of the active fixation tines are positioned adjacent to the patient tissue.

Abstract: A method of determining pacing therapy for an individual patient including determining representative electromechanical physiologic characteristics for a plurality of normal patients having a range of anatomical dimensions and developing a plurality of normal templates. Each template indicates the representative electromechanical physiologic characteristics of a group of normal patients having similar anatomical dimensions.

Abstract: Exemplary lead assemblies include a lead body having a plurality of conductor wires embedded therein, a plurality of electrode contacts at least partially disposed on an outer surface of the lead body, and a plurality of switching networks each configured to control an operation of one or more of the plurality of electrode contacts.

Abstract: An implantable lead having a distal assembly including a coupler, a fixation helix secured to the coupler, a housing in which the fixation helix and the coupler are disposed, and a resilient seal that is fixedly secured to the coupler between proximal and distal ends thereof and able to translate with the coupler relative to the housing. The seal is positioned to sealingly engage an internal surface of the housing. When the coupler is translated such that the fixation helix is in a fully extended position, the seal is positioned to substantially seal off the housing to prevent tissue ingrowth.

Abstract: A lead includes a conductor having a distal end and a proximal end and a resonant circuit connected to the conductor. The resonant circuit has a resonance frequency approximately equal to an excitation signal's frequency of a magnetic resonance imaging scanner or a resonance frequency not tuned to an excitation signal's frequency of a magnetic resonance imaging scanner so as to reduce the current flow through a tissue area, thereby reducing tissue damage. The resonant circuit may be included in an adapter that provides an electrical bridge between a lead a medical device such as an electrode, sensor, or signal generator. The resonant circuit may also be included directly in the housing of a medical device.

Abstract: An implantable lead includes a lead body, having a distal end and a proximal end, configured to be implanted in a patient, and a connector provided at the proximal end. A load detection assembly is provided on the lead body, wherein the load detection assembly includes a housing that holds a sensor and a load transfer element. The load transfer element engages the sensor and conveys a force induced on the load transfer element to the sensor. Optionally, the housing may isolate the sensor from lateral forces and the load transfer element may only convey, to the sensor, longitudinal forces that are directed in a predetermined single direction. For example, the load transfer element may only convey, to the sensor, longitudinal forces that are directed perpendicular to a surface of the sensor.

Abstract: Implantable medical device with at least one long extended electrical conductor that is insulated from the surrounding material by a dielectric having an inside diameter diel including an electrode pole for emitting therapy signals or for detecting diagnostic signals that represents in the implanted state a load characteristic capacitance ZL for electromagnetic radio frequency waves; having between its proximal end and the electrode pole at least one first longitudinal section of a first characteristic impedance Z0 for electromagnetic radio frequency waves; and including immediately adjacent to the first longitudinal section at least one second longitudinal section, at least 0.25 inside diameters (diel) long, which is shorter in comparison to the first longitudinal section having a second characteristic impedance Z1 for electromagnetic radio frequency waves, and wherein the second characteristic impedance is either larger or smaller than the load characteristic impedance.

Abstract: An implantable medical electrical lead includes an extendable/retractable active fixation distal tip assembly. The distal tip assembly includes a shell having an internal cavity and a helix guide member extending at least partially across the cavity and including an axial surface. The distal tip assembly also includes a rotatable coupler within the cavity and a fixation helix fixedly attached to the coupler. The fixation helix engages the helix guide member such that rotation of the coupler and the fixation helix causes the coupler and the fixation helix to advance distally relative to the shell. The coupler further includes a distal rotation stop member protruding axially from the coupler configured to abut the axial surface of the helix guide member to delimit rotation and extension of the coupler and the fixation helix.

Abstract: Temporarily or permanently implantable medical device, having at least one longitudinally extended first electrical conductor having a functional lead, which is connected to a functional electrode pole for dispensing therapeutic signals or for detecting diagnostic signals, and including at least one second electrical conductor, which is coupled to the functional lead and is guided with it in a shared insulating sheathing, such that a coupling between the functional lead and the second electrical conductor is designed to input electromagnetic radiofrequency waves guided in the functional lead at least partially into the second electrical conductor.

Abstract: One aspect relates to a medical implant, for example, implantable stimulation electrode, having a tight substrate and a porous contact region. One aspect also relates to a lead of a cardiac pacemaker having an implantable stimulation electrode and to a method for manufacturing a medical implant, for example, an implantable stimulation electrode. A medical implant according to one aspect is characterized in that the implant includes a sintered body with graduated porosity.

Abstract: A temporarily or permanently implantable medical device having at least one elongated electrical function conductor for transmitting therapeutic signals or diagnostic signals or both. At least one additional conductor is provided which together with the function conductor forms, at least in places, a double line which is separated from the function conductor by a dielectric and which is coupled to the function conductor via a coupling impedance. The coupling impedance is dimensioned so that the value of the line wave impedance of the function conductor for frequency ranges far above a frequency range of the therapeutic or diagnostic signals is much greater than the in the frequency range of the therapeutic or diagnostic signals, so that currents in a frequency range above the frequency range of the therapeutic or diagnostic signals are damped more intensely than the currents which form therapeutic or diagnostic signals.

Abstract: An implantable medical device having at least one electrical conductor that extends longitudinally and includes a functional lead. The functional lead is connected to an electrode pole to discharge therapeutic signals or to detect diagnostic signals, wherein the functional lead or the electrode pole, or both the functional lead and the electrode pole, are constructed with a ring shape in a first longitudinal section. The electrical conductor includes at least one second electrical lead which is routed in a spiral shape in the first longitudinal section in such a manner that electromagnetic radio frequency waves which can be conducted in the first electrical lead can be coupled into the second electrical lead in the first longitudinal section.

Abstract: An implantable medical device, which is connected or is to be connected to at least two elongated electric function conductors for the transmission of treatment signals or diagnostic signals or both, and at least one electrode pole connected to at least one of the function conductors, via which electrode pole electric current can be delivered in the case of use to surrounding tissue of the body or with which electric potentials can be sensed in the surrounding tissue or both. Includes a wave transfer module connected to the function conductor and which is embodied to transform waves arriving via a function conductor and to switch them as transformed waves onto another function conductor or the same function conductor in such a controlled manner that the waves are destructively superimposed at the electrode pole.

Abstract: An implantable medical device having at least one first and one second longitudinally extended electrical functional conductor for transmitting therapeutic signals or diagnostic signals or both and one electrode pole connected to the functional conductor, the electrical current being delivered to the surrounded bodily tissue in the use case by means of this electrode pole or with which electrical potentials can be sensed in the surrounding tissue in the use case or both, such that the two electrical functional conductors are inductively coupled for defined resonant frequencies such that RF energy of a first functional conductor is diverted to the second functional conductor and the energy is delivered to the surrounding tissue in the use case via this functional conductor and via an electrode pole connected to this functional conductor.

Abstract: An apparatus and method can receive wireless energy using a wireless electrostimulation electrode assembly. In certain examples, at least some of the received wireless energy can be delivered as an electrostimulation to a heart. In certain examples, the wireless electrostimulation electrode can be mechanically supported at least partially using a ring formed by an annulus of a mitral valve of the heart. In certain examples, the wireless electrostimulation electrode assembly can be configured to be intravascularly delivered to an implant location within a chamber of the heart at the annulus of the mitral valve of the heart, and can fit entirely within the heart.

Abstract: A lead for active implantable medical devices comprising a chip, notably for electrode multiplexing. The lead (10) includes an insulating supporting tube (20) interposed in a flexible elongated tube, with a central bore (22) coaxial with the lumen of the lead. The supporting tube comprises on its surface at least one crossing conductive strip (28) extending in the axial direction. A chip (18) on a flexible substrate is disposed with a bent or curved conformation in a receptacle of the supporting tube isolated from the conductive strip. An electrode, e.g., for cardiac sensing/pacing, (16) on the supporting tube (20) is electrically connected to an outer conductive pad (24) of the chip. The conductive strip is connected (i) at each end (28b), face to face to a conductive connection (12), housed in the sheath, and (ii) in a central region (28a), to an inner conductive pad (26) of the chip.

Abstract: In general, the disclosure is directed toward releasing material within a medical device via an optical feedthrough. A system for releasing material with a medical device comprises a cup that holds a material, wherein the cup includes a discharge port, a seal disc that seals the material within the cup, an optical feedthrough assembly coupled to the cup, a shell that defines a chamber within a medical device, wherein the optical feedthrough assembly is coupled to the shell, and a radiant energy source that shines a beam through the optical feedthrough assembly to puncture the seal disc to allow the material to enter the chamber via the discharge port.