Abstract: External cardiac defibrillators that include automatic or semi-automatic self-contained defibrillators to be used by non-health professionals (physicians, nurses and other specifically trained persons). A power subassembly in an automatic or semi-automatic cardiac defibrillator system which, associated with a computer device, is capable of diagnosing a patient's condition by performing a simplified electrocardiogram, transmitting the data to the electronic device and supplying, controlled by this device, electric shocks to the patient, and also providing or contributing to further ancillary defibrillation functions.

Abstract: A defibrillator is described which executes a resuscitation protocol having a CPR pause period. The CPR pause period may be interrupted for the acquisition of ECG signal data which is not contaminated by chest compression artifacts. Following the acquisition of ECG signal data, the CPR period resumes and continues for its full period. The ECG signal data acquired during the interruption of the CPR period is analyzed and, if a shockable rhythm is identified, a shock sequence is initiated immediately upon conclusion of the CPR period.

Abstract: A system includes a first computing device comprising a processor coupled to a memory. The processor and the memory are configured to receive at least one of (i) information indicative of treatment of a victim by a first caregiver using the first computing device and (ii) information indicative of a health status of the victim; determine that treatment of the victim by the first caregiver using the first computing device is completed; and transmit the received information to a second computing device.

Abstract: A defibrillator system optimizes the timing and manner of applying a defibrillator charge to a patient based upon data provided to the defibrillator from a utility module or one or more external devices. A parameter module on the utility module provides the defibrillator with patient parameter information. Devices external to the utility module may provide the utility module with coaching data that the utility module may pass through to the defibrillator as a proxy to the external devices. The utility module may also provide external devices with patient data that the utility module may pass through to the external devices as a proxy to the defibrillator on a scheduled or other basis. The utility module may additionally provide a reserve of power to enable defibrillators to be used where power is unavailable and to enable defibrillators to deliver multiple charges more readily anywhere, anytime.

Abstract: A semi-automated AED with a second shock switch. In an illustrative embodiment, programming running on the AED after prompting a user of the AED to push a shock switch looks to see if an event associated with pushing the shock switch, such as the delivery of a shock, has occurred. If the event being monitored for has not occurred within a given time, the user is prompted to push another button to initiate the event.

Abstract: One embodiment of an electrode lead comprises a lead body, at least one electrode at a distal end of the lead body, an actuatable member and at least one anchor wire. The actuatable member is positioned within a lumen of the lead body. The at least one anchor wire has a proximal end that is attached to the actuatable member. Movement of the actuatable member relative to the lead body moves the at least one anchor wire through at least one opening in the lead body.

Abstract: Disclosed is a method for the diagnosis of conductor anomalies, such as an insulation failure resulting in a short circuit, in an implantable medical device, such as an implantable cardioverter defibrillator (ICD). Upon determining if a specific defibrillation pathway is shorted, the method excludes the one electrode from the defibrillation circuit, delivering defibrillation current only between functioning defibrillation electrodes. Protection can be provided against a short in the right-ventricular coil-CAN defibrillation pathway of a pectoral, transvenous ICD with a dual-coil defibrillation lead. If a short caused by an in-pocket abrasion is present, the CAN is excluded from the defibrillation circuit, delivering defibrillation current only between the right-ventricular and superior vena cava defibrillation coils. Determination that the defibrillation pathway is shorted may be made by conventional low current measurements or delivery of high current extremely short test pulses.

Abstract: An accessory kit for use with a wearable medical device, such as a wearable defibrillator, that includes a control unit and a first plurality of electrodes electrically coupled to the control unit. The first plurality of electrodes includes a first plurality of ECG sensing electrodes and a first plurality of therapy electrodes configured to provide a defibrillating shock to a body of a patient. The accessory kit includes a waterproof enclosure configured to receive the control unit and protect the control unit during operation in a wet environment and a second plurality of electrodes that are electrically coupled to a connector configured to removably and electrically couple to the control unit. The second plurality of electrodes includes a second plurality of ECG sensing electrodes and a second plurality of therapy electrodes configured to provide a defibrillating shock to the body of the patient.

Abstract: An instrument is described for assisting a rescuer in the proper administration of CPR. A sensor detects movement of the chest caused by ventilation. The sensor signals are processed to produce a control signal representative of the effectiveness of the ventilation. A lung icon is displayed in the outline shape of human lungs and the outline is displayed filled to a level which indicates the effectiveness of the ventilation.

Abstract: Automated treatment of arrhythmia utilizing an electrotherapy device. Time-coordinated applications of medium-voltage therapy (MVT) followed by high-voltage therapy (HVT) include a first MVT waveform to a first target region and a second MVT waveform to a second target region, such that the HVT is synchronized relative to a first compression cycle corresponding to activation of the first target region, and to a second compression cycle corresponding to activation of the second target region resulting from the administration of the MVT.

Abstract: An example system and method of locating a source of a heart rhythm disorder are disclosed. In accordance with the method, a first pair of cardiac signals is processed to define a first coefficient associated with variability of the first pair of signals at a first region of the heart. Further, a second pair of cardiac signals is processed to define a second coefficient associated with variability of the second pair of signals at a second region of the heart. Thereafter, the first coefficient of variability is compared to the second coefficient of variability to determine a direction towards the source of the rhythm disorder.

Abstract: Implanted pulse generators with reduced power consumption via signal strength-duration characteristics, and associated systems and methods are disclosed. A representative method for treating a patient in accordance with the disclosed technology includes receiving an input corresponding to an available voltage for an implanted medical device and identifying a signal delivery parameter value of an electrical signal based on a correlation between values of the signal delivery parameter and signal deliver amplitudes. The signal deliver parameter can include at least one of pulse width or duty cycle. The method can further include delivering an electrical therapy signal to the patient at the identified signal delivery parameter value using a voltage within a margin of the available voltage.

Abstract: A diagnostic medical device for identifying an arrhythmia treatable by a defibrillation shock includes a defibrillating a filter for filtering ECG data sets, a classifier and a electrotherapy circuit. The classifier is configured to classify filtered and unfiltered ECG data sets as a “shock” advice or a “no-shock” advice.

Abstract: An implantable cardioverter-defibrillator system that includes at least one or more stimulation units, one or more detection units, one or more control units, two or more electrode poles and one or more high voltage capacitors. The at least one control unit is connected with the at least one stimulation unit, and the at least one control unit is connected with at the least one detection unit. The two or more electrode poles are in contact with body tissue, and the one or more high voltage capacitors are charged by at least one charging unit, wherein the at least one charging unit is connected to the at least one control unit.

Abstract: Systems of techniques for controlling charge flow during the electrical stimulation of tissue. In one aspect, a method includes receiving a charge setting describing an amount of charge that is to flow during a stimulation pulse that electrically stimulates a tissue, and generating and delivering the stimulation pulse in a manner such that an amount of charge delivered to the tissue during the stimulation pulse accords with the charge setting.

Abstract: There is provided an energy delivery device comprising a storage device, a discharge circuit and a disarm circuit. The discharge circuit comprises a switch electrically connected to the storage device, and is selectively operable to deliver energy from the storage device to a load, e.g., a patient needing defibrillation, preferably in a multiphasic waveform. The disarm circuit comprises the switch. Preferably, the discharge circuit comprises an H-bridge circuit. There are also provided delivery devices: which comprise a shoot-through elimination circuit; which include housing elements which, when assembled, cause electrical connection between respective components; which include a housing having a small volume and an energy storage device having a large capacitance; which comprise a shunt circuit which, when activated, prevents switching of a switch. There are also provided methods of assembly and disassembly of an energy delivery unit and methods of delivering energy to a load.

Abstract: Systems and methods of providing life support are provided. A life support system includes a first life support device that has a control unit and is configured to apply a life support protocol to a subject. The first life support device also includes a memory unit that can store life support protocol information, and the control unit can provide the life support protocol information to a second life support device. The control unit can also receive operating instructions from the second life support device based on the life support protocol information, and can implement the operating instructions.

Abstract: A medical device for caring for a patient includes a patient utility for measuring a patient parameter or administering a therapy to the patient and an alarm system that has a receiver to accept status information about the medical device. A use detector of the alarm system is structured to determine when the medical device is being prepared for use and a status detector of the alarm system is adapted to determine from the status information that the medical device is in a ready state. The alarm system further includes an alarm that is activated when the medical device is both being prepared for use and not in the ready state. This description also includes methods of generating an alarm when the medical device is both being prepared for use and not in the ready state.

Abstract: Apparatus is configured to drive first action potentials orthodromically in a first direction along a nerve of a subject, and second action potentials orthodromically along the nerve in an opposite direction to the first direction. The apparatus includes: (1) first and second excitation units configured to be placed in a proximity of the nerve of the subject; (2) a blocking unit disposed between the excitation units and placeable in a proximity of the nerve of the subject; and (3) a control unit, configured: (i) to drive the first and second excitation units to apply, respectively, first and second excitatory currents to the nerve of the subject, and (ii) to drive the blocking unit to apply a blocking current to the nerve of the subject that blocks action potentials that propagate from the first and second excitatory units toward the blocking unit. Other embodiments are also described.

Abstract: An implantable electroacupuncture device (IEAD) treats obese conditions of a patient through application of stimulation pulses applied at acupoints SP4, LR8 or ST40, or their underlying nerves saphenous and peroneal. The IEAD comprises an implantable, coin-sized, self-contained, leadless electroacupuncture device having at least two electrodes attached to an outside surface of its housing. The device generates stimulation pulses in accordance with a specified stimulation regimen. Power management circuitry within the device allows a primary battery, having a high internal impedance, to be used to power the device. The stimulation regimen generates stimulation pulses during a stimulation session of duration T3 minutes applied every T4 minutes. The duty cycle, or ratio T3/T4, is very low, no greater than 0.05. The low duty cycle and careful power management allow the IEAD to perform its intended function for several years.

Abstract: Physiological monitoring can be provided through a wearable monitor that includes two components, a flexible extended wear electrode patch and a removable reusable monitor recorder. The wearable monitor sits centrally (in the midline) on the patient's chest along the sternum oriented top-to-bottom. The placement of the wearable monitor in a location at the sternal midline (or immediately to either side of the sternum) benefits extended wear by removing the requirement that ECG electrodes be continually placed in the same spots on the skin throughout the monitoring period. Instead, the patient can place an electrode patch anywhere within the general region of the sternum. Power is provided through a battery provided on the electrode patch, which avoids having to open the monitor recorder's housing for battery replacement. The monitor further includes sensors for monitoring patient's air flow and respiratory measures contemporaneously with the ECG monitoring.

Abstract: A medical ventilation monitoring system includes a patient ventilation unit defining an airflow path, the unit arranged so that when the unit is applied to a patient, the airflow path is in fluid communication with the patient's airway; an airflow sensor in the air flow path positioned to sense the presence of ventilation airflow to or from the patient; and a wireless transceiver arranged to receive data that is generated by a portable medical device, and to use the data to provide feedback to a rescuer regarding proper administration of ventilation.

Abstract: An implantable medical device (IMD) including a power supply, a sensing device and/or a stimulation device, a control unit, a magnetic resonance (MR) detection unit, and at least two magnetic field sensors. The power supply is connected to one or more of the sensing device, the stimulation device, the control unit, the MR detection unit and the magnetic field sensors. The control unit is connected to the sensing device and/or stimulation device, to the MR detection unit, and to the at least two magnetic field sensors. The at least two magnetic field sensors are arranged spatially separately from one another and the MR detection unit determines a spatial and/or temporal gradient of magnetic field strengths detected by the at least two magnetic field sensors and transmitted to the MR detection unit. The MR detection unit detects an MR field and transmits an MR signal to the control unit.

Abstract: An implantable medical device configured to be compatible with the environment inside an MRI machine. The implantable medical device includes a housing constructed of an electrically conductive material and pulse generation circuitry within the housing for generating electrical voltage pulses. The implantable medical device further includes a first conductor that is configured to transmit the electrical voltage pulses from the pulse generation circuitry to a patient's cardiac tissue and a second conductor that is configured to provide an electrically conductive path from the patient's cardiac tissue back to the pulse generation circuitry. The implantable medical device further includes a selectively interruptible electrically conductive path connecting the pulse generation circuitry with the housing.

Abstract: Monitoring physiological parameter using an implantable physiological monitor in order to detect a condition predictive of a possible future pathological episode and collecting additional physiological data associated with the condition predictive of a possible future pathological episode. Monitoring another physiological parameter in order to detect a condition indicative of the beginning of a present pathological episode and collecting additional pathological data in response to the condition. Determining that the condition predictive of a future episode and the condition indicative of a present episode are associated and, in response thereto, storing all the collected physiological data.

Abstract: Electronic devices may be accidentally exposed to liquid during operation. To detect liquid intrusion events, an electronic device may be provided with one or more electronic liquid contact sensors. The liquid contact sensors may have electrodes. Control circuitry may make measurements across the electrodes such as resistance and capacitance measurements to detect the presence of liquid. Liquid contact sensor data may be maintained in a log within storage in the electronic device. The liquid contact sensor data can be used to display information for a user of the electronic device or can be loaded onto external equipment for analysis. Liquid contact sensor electrodes may be formed from metal traces on substrates such as printed circuits, from contacts in a connector, from contacts on an integrated circuit, or from other conductive electrode structures.

Abstract: A medical device includes a display area that has a thin panel having a substantially flat front surface portion, a translucent layer on a back surface of the thin panel, a layer of text or graphics on a back surface of the translucent layer, and arranged so that the text or graphics is not visible to a user on the front side when light is not provided from inside the device housing. Also included is a switch to allow a user to select a first mode or a second mode for the device, and circuitry arranged to energize one or more light sources to provide light from behind the thin panel when the device is in the first mode, thereby making visible the text or graphics when the device is in the first mode.

Abstract: Aspects of the present invention are generally directed to taking measurements in a hearing prosthesis. In an embodiment, a power circuit, which may be a switched mode power circuit, is shut down during performance of the measurements to reduce interference. Then, power capacitively stored by the power circuit is used to power the hearing prosthesis during performance of the measurements. In an embodiment, the power circuit increases its voltage just prior to performance of the measurements. This serves to increase the amount of energy capacitively stored by the power circuit and thus extends the period of time during which the measurements may be taken while the power circuit is shut off.

Abstract: An ablation system including an image database storing a plurality of computed tomography (CT) images of a luminal network and a navigation system enabling, in combination with an endoscope and the CT images, navigation of a locatable guide and an extended working channel to a point of interest. The system further includes one or more fiducial markers, placed in proximity to the point of interest and a percutaneous microwave ablation device for applying energy to the point of interest.

Abstract: A method of enhancing the signal-to-noise ratio (SNR) of measured electrocardiogram (ECG) signals is provided. The method includes the steps of providing at least three cardiac input signals derived from the measured ECG signals S1 and forming a first estimate U1 S2 from each of at least three pairs of input signals. Moreover, the method includes the steps of forming a second estimate U2 S3 from each of at least three input signals; comparing S4 the polarity and the amplitude of a first and second estimate U1, U2 to at least one threshold T; generating S5 a composite signal X, wherein the polarity and the amplitude of the composite signal X depend on the result of the comparison; and using S6 the generated composite signal X to produce an output signal with enhanced signal-to-noise ratio (SNR). Furthermore, a corresponding cardiac device is also provided.

Abstract: A system and method for confirming arrhythmias in an implantable cardiac stimulation device senses electrical events in an intracardiac signal and identifies a potential arrhythmia based on the electrical events. The electrical events may be depolarization events occurring in a heart, such as R-waves or P-waves. The electrical events are high pass filtered and analyzed to confirm or reject the electrical events. The confirmed electrical events are then analyzed to determine whether the electrical events indicate a heart arrhythmia. A therapy may then be applied to the heart for treating the arrhythmia.

Abstract: Systems and techniques for providing text-based communications from medical equipment such as automated external defibrillators (AEDs) are described herein.

Abstract: A system and method to deliver a therapeutic quantity of energy to a patient. The system includes a capacitor having a rated energy storage capacity substantially equal to the therapeutic quantity of energy, a boost converter coupled with the capacitor and constructed to release energy from the capacitor at a substantially constant current for a time interval, and an H-bridge circuit coupled with the boost converter and constructed to apply the substantially constant current in a biphasic voltage waveform to the patient. The method includes storing a quantity of energy substantially equal to the therapeutic quantity of energy in a capacitor, releasing the quantity of energy at a relatively constant current during a time interval using a boost converter coupled with the capacitor, and delivering a portion of the quantity energy in a direction to the patient using an H-bridge circuit coupled with the boost converter.

Abstract: A defibrillator system optimizes the timing and manner of applying a defibrillator charge to a patient based upon data provided to the defibrillator from a utility module or one or more external devices. A parameter module on the utility module provides the defibrillator with patient parameter information. Devices external to the utility module may provide the utility module with coaching data that the utility module may pass through to the defibrillator as a proxy to the external devices. The utility module may also provide external devices with patient data that the utility module may pass through to the external devices as a proxy to the defibrillator on a scheduled or other basis. The utility module may additionally provide a reserve of power to enable defibrillators to be used where power is unavailable and to enable defibrillators to deliver multiple charges more readily anywhere, anytime.

Abstract: Methods and apparatus for a three-stage atrial cardioversion therapy that treats atrial arrhythmias within pain tolerance thresholds of a patient. An implantable therapy generator adapted to generate and selectively deliver a three-stage atrial cardioversion therapy and at least two leads, each having at least one electrode adapted to be positioned proximate the atrium of the patient. The device is programmed for delivering a three-stage atrial cardioversion therapy via both a far-field configuration and a near-field configuration of the electrodes upon detection of an atrial arrhythmia. The three-stage atrial cardioversion therapy includes a first stage for unpinning of one or more singularities associated with an atrial arrhythmia, a second stage for anti-repinning of the one or more singularities, both of which are delivered via the far-field configuration of the electrodes, and a third stage for extinguishing of the one or more singularities delivered via the near-field configuration of the electrodes.

Abstract: A method of modifying the force of contraction of at least a portion of a heart chamber, including providing a subject having a heart, comprising at least a portion having an activation, and applying a non-excitatory electric field having a given duration, at a delay after the activation, to the portion, which causes the force of contraction to be increased by at least 5%.

Abstract: This disclosure provides an implantable medical device comprising a power source a therapy module that includes at least one energy storage component, and a charging module coupled between the power source and the therapy module. The charging module is configured to control charging of the at least one energy storage component of the therapy module. The charging module may be further configured to detect a condition indicative of improper charging, to detect a condition indicative of the implantable medical device being subjected to fields generated by an magnetic resonance imaging (MRI) device, and to terminate charging of the at least one energy storage component when both the condition indicative of improper charging and the condition indicative of the implantable medical device being subjected to fields generated by the MRI device are detected.

Abstract: Electrical circuit componentry is switchable into a defibrillator circuit to deliver a constant pacing current to a patient. The circuitry may include a constant current source inserted in a leg of the defibrillator circuit or a resistor of selected value inserted between a high voltage source and the high side of a defibrillator circuit.

Abstract: An implantable medical device system detects and treats monomorphic ventricular tachycardia (VT). The system includes a sensing module for receiving a cardiac signal and a therapy delivery module including a capacitor and an output circuit. A control module is coupled to the sensing module and the therapy delivery module and is configured to detect a tachycardia from the cardiac signal and initiate charging of the capacitor in response to detecting the tachycardia. The control module performs a method for simultaneously monitoring a voltage on the capacitor and a morphology of the cardiac signal during the charging and controls the therapy delivery circuit to deliver a shock pulse at less than a programmed shock energy in response to both the voltage reaching at least a minimum voltage and the morphology being monomorphic.

Abstract: Systems and methods for testing defibrillator electrode conductivity. Connection for electrically connecting electrodes and defibrillation signal generator connected to the electrodes. Patient impedance measurement system comprising patient signal generator and patient signal receiver. A defibrillator controller connected to defibrillation signal generator and patient impedance measurement system.

Abstract: A system and method are described herein including an implantable medical device (IMD) configured to be programmed with magnetic resonance imaging (MRI) settings for use during an MRI scan, wherein the IMD stores identity data that uniquely identifies the IMD or a patient having the IMD. The system includes an external storage media configured to receive MRI settings associated with the IMD and configured to store the MRI settings associated with the IMD. The system also includes a programmer configured to retrieve identity data from IMD, retrieve MRI settings associated with the IMD from the external storage media and program the IMD using the MRI settings.

Abstract: A wireless charging apparatus and a wireless charging system using the same are provided. The wireless charging apparatus includes a sensing resonator that senses for an external device; a transmission resonator that transmits energy to the external device by magnetic resonance; and a transmission circuit that controls the transmission resonator in accordance with an output of the sensing resonator.

Abstract: The invention provides a sensor for measuring both impedance and ECG waveforms that is configured to be worn around a patient's neck. The sensor features 1) an ECG system that includes an analog ECG circuit, in electrical contact with at least two ECG electrodes, that generates an analog ECG waveform; and 2) an impedance system that includes an analog impedance circuit, in electrical contact with at least two (and typically four) impedance electrodes, that generates an analog impedance waveform. Also included in the neck-worn system are a digital processing system featuring a microprocessor, and an analog-to-digital converter. During a measurement, the digital processing system receives and processes the analog ECG and impedance waveforms to measure physiological information from the patient. Finally, a cable that drapes around the patient's neck connects the ECG system, impedance system, and digital processing system.

Abstract: This disclosure describes generation of electrical stimulation pulses for electrical stimulation therapy. The stimulation pulses have a pulse current level and pulse width, and may be generated by a current regulator. The pulse voltage level may be a voltage level delivered by the current regulator while maintaining regulation of the pulse current level. During delivery of a pulse, a supply voltage level may decrease due to discharging of a supply capacitance, and the pulse voltage level may increase due to charging of a load capacitance. The pulse current level may be controlled to decrease during the pulse width such that a sum of the pulse voltage level and a headroom voltage of the current regulator does not exceed the supply voltage level. In some examples, the pulse may include sub-pulses with different sub-pulse current levels, where an earlier sub-pulse has a higher pulse current level than a later sub-pulse.

Abstract: A language controller (20) is described which can be installed on the front face of an automated external defibrillator (AED) in order to establish the language of the AED user interface. The language controller is in the form of a labeled plaque (210) which informs the user which language is currently in use. The plaque may also contain a button (222) which enables toggling from one language to another. Memory may also reside in the plaque to provide language data to the AED.

Abstract: Methods and apparatus are provided for determining a defibrillation treatment protocol in an external defibrillator whereby a user may override a CPR-first default protocol. The method includes following steps configured in a defibrillator controller of issuing an inquiry; waiting for a response to the inquiry for a set time; ordering a CPR treatment protocol if no response is received within the set time; analyzing a response; ordering a CPR treatment protocol upon receiving a non-affirmative response to the inquiry; and ordering a shock treatment protocol upon receiving an affirmative response to the inquiry. Upon selecting a shock treatment protocol, the defibrillator performs a shock analysis under the shock treatment protocol, and either orders a CPR treatment protocol if shock treatment is not indicated by the shock analysis or provides a defibrillation shock if shock treatment is indicated by the shock analysis. Queries may be presented to a user in visual, audible, or both visual and audible format.

Abstract: A defibrillator (1) comprising electrodes (3), a connection (5) for electrically connecting the electrodes together, a defibrillation circuit (9) connected to the electrodes, and an electrode test system (7), comprising a test initiation device operable to generate a test initiating signal, a test signal generator (15) operable to generate a dc voltage test signal, a test signal switch (17) connected to the electrodes and, on receipt of the test initiating signal, operable to connect the electrodes to the test signal generator for passing the dc voltage test signal to the electrodes, and a test processing device (19) connected to the test signal switch to receive a dc voltage electrode return signal and process the electrode return signal to determine a pass test result or a fail test result for the electrodes.

Abstract: A computer-implemented method for providing summary information for lifesaving activities is disclosed. The method involves sensing one or more activities that are repeatedly and cyclically performed on a victim by a rescuer; identifying a cyclical timing interval over which performance is to be analyzed for a integer number of cycles of the one or more activities, and gathering data from the sensing of the one or more activities during the time interval; generating, from analysis of the one or more activities, summary data that condenses data sensed for the one or more activities into a summary of the one or more activities; and providing, for display to a user, a visual summary of the performance of the one or more activities over the identified time interval.

Abstract: A method includes making a device capable of administering an electrical shock to a patient and operable with a smartphone. The steps include providing a case; providing an automated external defibrillator fitting within the case; providing a case input/output port to the automated external defibrillator that mates with a corresponding smartphone input/output port; and providing foldable pads fitting within the case. Each foldable pad has electrodes that are electrically connectable to the automated external defibrillator. Each foldable pad is unfolded to expose a surface of each electrode to be placed in contact with the skin of the patient. Additional steps may include providing on non-volatile memory a combined operating system for both a smartphone and the automated external defibrillator such that the combined operating system auto loads upon starting the device after connection of the smartphone to the case input/output port.

Abstract: Methods of cardiac rhythm analysis in an implantable cardiac stimulus device, and devices configured for such methods. In an illustrative embodiment, certain data relating to cardiac event rate or amplitude is modified following delivery of a cardiac stimulus. In another embodiment, cardiac rhythm analysis is performed using one of plural states, with the plural states using different criteria, such as a detection threshold, to detect cardiac events in a sensed signal. Following delivery of a cardiac stimulus, data is manipulated to force the analysis into one of the states, where stimulus is delivered, in the illustrative embodiment, only after a different state is invoked. Implantable devices incorporating operational circuitry for performing such methods are also included in other illustrative embodiments.