Abstract: Apparatus using one or more modes of statistical analysis with one or more monitored parameters of a patient's heart to identify and/or assess arrhythmias. Through use of the one or more modes of statistical analysis, a medical professional can be aided during evaluation of patient data for diagnosis of the patient. At least one of the monitored parameters may include one or more values used representatively for storage intervals of a selected length. As such, for each storage interval, a value may be determined for the one monitored parameter occurring at an upper percentile and a lower percentile. In addition, a median value may be determined for the one monitored parameter for each storage interval. Over a plurality of the storage intervals, these determined values can be used in one or more modes of statistical analysis to better identify and assess the arrhythmias.

Abstract: Medical devices and methods for providing breathing therapy (e.g., for treating heart failure, hypertension, etc.) may determine at least the inspiration phase of one or more breathing cycles based on the monitored physiological parameters and control delivery of a plurality of breathing therapy sessions (e.g., each of the breathing therapy sessions may be provided during a defined time period). Further, each of the plurality of breathing therapy sessions may include delivering stimulation after the start of the inspiration phase of each of a plurality of breathing cycles to prolong diaphragm contraction during the breathing cycle.

Abstract: A medical device for monitoring a patient condition includes a sensor capable of being advanced transvascularly to be positioned along a volume of tissue, the sensor including a first combination of a light source and a light detector to emit light into a volume of tissue and to detect light scattered by the volume of tissue and to generate a first output signal corresponding to an intensity of the detected light. A control module is coupled to the light source to control the light source to emit light at least four spaced-apart light wavelengths, and a monitoring module is coupled to the light detector to receive the output signal and compute a measure of tissue oxygenation using the light detector output signal.

Abstract: Systems and methods for monitoring phrenic nerve function of a patient are disclosed, including, including establishing a diaphragmatic movement value threshold; positioning a diaphragmatic movement sensor on an external surface of an abdomen of the patient; applying a treatment regimen to a tissue region in proximity to the phrenic nerve; measuring a diaphragmatic movement value with the diaphragmatic movement sensor; comparing the measured diaphragmatic movement value to the established diaphragmatic movement value threshold; and generating an alert in response to the comparison.

Abstract: A fluid status monitoring system for use in implantable cardiac stimulation or monitoring devices is provided for monitoring changes in thoracic fluid content. A fluid status monitor includes excitation pulse generating and control circuitry, and voltage and current measurement and control circuitry for performing a series of cardiac-gated, intra-thoracic impedance measurements. The cardiac-gated measurements are filtered or time-averaged to provide a fluid status impedance value, with respiratory noise removed. Based on comparative analysis of the fluid status impedance value, a clinically relevant trend in fluid status may be tentatively diagnosed and a fluid status response provided. Cross-check intra-thoracic impedance measurements performed using the same or a different excitation pathway and a different measurement pathway than the primary intra-thoracic impedance measurement configuration may be used to verify a tentative diagnosis.

Abstract: Techniques for controlling therapy based on a physiological parameter indicative of ventricular filling pressure, such as various cardiovascular pressures, are described. One or more values of the physiological parameter that are collected during nighttime, or while the patient is otherwise asleep, inactive, or within a recumbent position, may be compared to one or more values of the physiological parameter collected during daytime, or while the patient is otherwise awake, active and/or upright. A therapy, such as for treating physiological factors that may lead to worsening HF, may be initiated or adjusted based on the comparison, e.g., if the nighttime values exceed the daytime values.

Abstract: A method of determining a respiration parameter in a medical device in which pressure signals are sensed to generate corresponding sample points, and a breath detection threshold is continuously adjusted in response to the generated sample points to generate a current adjusted breath detection threshold. A current generated sample point is compared to the current adjusted breath detection threshold, and the continuous adjusting of the breath detection threshold is suspended and the breath detection threshold is equal to the most current adjusted breath detection threshold generated prior to the suspending in response to the comparing. A next sample point, generated subsequent to the suspending, is compared to the set breath detection threshold, and the respiration parameter is determined in response to the comparing of a next sample point to the set breath detection threshold.

Abstract: Medical devices and methods for providing breathing therapy (e.g., for treating heart failure, hypertension, etc.) may determine at least the inspiration phase of one or more breathing cycles based on the monitored physiological parameters and control delivery of a plurality of breathing therapy sessions (e.g., each of the breathing therapy sessions may be provided during a defined time period). Further, each of the plurality of breathing therapy sessions may include delivering stimulation after the start of the inspiration phase of each of a plurality of breathing cycles to prolong diaphragm contraction during the breathing cycle.

Abstract: A medical device for monitoring a patient condition includes a first combination of a light source and a light detector to emit light into a volume of tissue, detect light scattered by the volume of tissue, and provide a first output signal corresponding to an intensity of the detected light. A control module is coupled to the light source to control the light source to emit light at least four spaced-apart light wavelengths, and a monitoring module is coupled to the light detector to receive the output signal, compute a measure of tissue oxygenation in response to the light detector output signal, and detect tissue hypoxia using the measure of tissue oxygenation.

Abstract: The present invention provides a method and apparatus for detecting and monitoring obstructive sleep apnea. The apparatus measures sinus tachycardia and a change in the atrial-ventricular conduction, and includes a controller for receiving the measurement of the sinus tachycardia and the change in the atrial-ventricular conduction to detect obstructive sleep apnea based upon the sinus tachycardia and the change in the atrial-ventricular conduction.

Abstract: A medical device for determining a respiratory effort having a pressure sensor to sense pressure signals, a housing having system components positioned therein, and a microprocessor positioned within the housing, wherein the microprocessor detects an inspiration and an expiration in response to the pressure signals, detects a breath in response to the detected inspiration and the detected expiration, and determines the respiratory effort in response to the detected breath.

Abstract: A method of determining respiratory effort in a medical device in which pressure signals are sensed to generate corresponding sample points, an inspiration and an expiration are detected in response to the sensed pressure signals, a breath is detected in response to the detected inspiration and the detected expiration, and the respiratory effort is determined in response to the detected breath.

Abstract: A system and method for deliverying an ablation therapy that includes delivering the ablation therapy, delivering drive signals to establish a drive signal vector fields, determining impedance signals in response to the drive signals, determining a first impedance parameter in response to the first impedance signal and a second impedance parameter in response to the second impedance signal, determining whether there is a change in a hemodynamic status of the tissue subsequent to delivery of the ablation therapy in response to the first impedance parameter and the second impedance parameter, and adjusting delivery of the ablation therapy in response to determining whether there is a change in a hemodynamic status of the tissue.

Abstract: An implantable medical device system and associated method deliver drive signals having different frequencies to establish vector fields comprising an arterial volume and a venous volume corresponding to targeted portion of a patient's body. Impedance signals are determined in response to drive signals having different frequencies. Impedance parameter values are determined over time. A change in the hemodynamic status of a targeted portion of the patient's body is identified in response to the impedance parameter values.

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: A medical device and method for determining baroreflex sensitivity (BRS) based on one or more respiration cycles. The BRS determination may be performed continuously based on measurements of heart rate, blood pressure, and respiration cycles.

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: Various techniques for measuring cardiac cycle length and pressure metrics based on pulmonary artery pressures are described. One example method described includes identifying a point within a derivative signal of a cardiovascular pressure signal without reference to electrical activity of a heart, initiating a time window from the identified point in the derivative signal, identifying a point within the cardiovascular signal within the time window, and determining at least one of a systolic pressure or diastolic pressure based on the identified point.

Abstract: Various techniques for measuring cardiac cycle length and pressure metrics based on pulmonary artery pressures are described. One example method described includes identifying a point within a derivative signal of a cardiovascular pressure signal without reference to electrical activity of a heart, initiating a time window from the identified point in the derivative signal, identifying a point within the cardiovascular signal within the time window, and determining at least one of a systolic pressure or diastolic pressure based on the identified point.

Abstract: Heart failure decompensation is detected by sensing at least one physiological signal. Values of at least two different heart failure variables are derived using one or more physiological signals and a threshold for the first heart failure variable is adjusted in response to the value of the second heart failure variable. The value of the first heart failure variable is compared to first threshold for detecting a heart failure condition.