60 results about "Ventricular pressure" patented technology

The implantable medical device (IMD) system disclosed here utilizes one or more cardiac sensors that measure mechanical characteristics of the heart, such as left ventricular acceleration or right ventricular pressure. The raw sensor data is collected and processed by the IMD, which derives one or more mechanical event marker signals from features, traits, and characteristics of the sensor data waveforms. The mechanical event marker signals are wirelessly transmitted to an external monitor device for display.

Devices and methods for left ventricular or biventricular pacing plus left ventricular pressure measurement. For example, a pacing lead having a combined electrode and pressure sensor assembly may be used for left ventricular (LV) pacing and pressure measurement. The assembly may include one or more electrodes, a pressure sensor, and a pressure transmission catheter. Such a pacing lead is particularly suitable for biventricular pacing and may be incorporated into a cardiac resynchronization therapy (CRT) system, for example.

A method and apparatus for determining whether a patient with congestive heart failure (CHF) will benefit from pacing therapy through the use of an implantable cardiac rhythm management device. A patient's right ventricular and left ventricular pressures are measured, and the patient's PP_Area is calculated for each normal heartbeat that occurs during the testing period. Depending upon the value of the patient's mean PP_Area, it can be determined whether the patient will or will not respond well acutely to pacing therapy. A mean PP_Area value of greater than or equal to a predetermined threshold, which is about 0.3, indicates that the patient is a responder to pacing therapy, while a value of less than the predetermined threshold of about 0.3 indicates that the patient is a non-responder.

Methods and devices for improving ventricular contractile status of a patient suitably exploit changes in ventricular pressure and / or dP / dtmax to provide and / or optimize a response to a patient. The ventricular pressure may be appropriately correlated to intracellular calcium regulation, which is indicative of contractile status. To assess ventricular contractile status, the device suitably observes a cardiac perturbation of the patient and measures force interval potentiation following the perturbation. The contractile potentiation can then be stored and / or quantified in the implantable medical device to determine the ventricular contractile status of the patient, and an appropriate response may be provided to the patient as a function of the ventricular contractile status. Examples of responses may include administration of drug or neuro therapies, modification of a pacing rate, or the like. Force interval potentiation may also be used to optimize or improve a parameter for a response provided by the implantable medical device.

Devices and methods for therapy control based on electromechanical timing involve detecting electrical activation of a patient's heart, and detecting mechanical cardiac activity resulting from the electrical activation. A timing relationship is determined between the electrical activation and the mechanical activity. A therapy is controlled based on the timing relationship. The therapy may improve intraventricular dyssynchrony of the patient's heart, or treat at least one of diastolic and systolic dysfunction and / or dyssynchrony of the patient's heart, for example. Electrical activation may be detected by sensing delivery of an electrical stimulation pulse to the heart or sensing intrinsic depolarization of the patient's heart. Mechanical activity may be detected by sensing heart sounds, a change in one or more of left ventricular impedance, ventricular pressure, right ventricular pressure, left atrial pressure, right atrial pressure, systemic arterial pressure and pulmonary artery pressure.

An intra-ventricular pressure sensor device is provided that includes a catheter having a first lumen for receiving fluid flow therethrough, and a second, separate, fluid-filled, fluid-impermeable lumen extending between a pressure-sensitive component that is adapted to be exposed to an external pressure source, and a pressure sensor that is effective to measure pressure of the external pressure source in response to displacement of the pressure-sensitive component. The intra-ventricular pressure sensor device is particularly advantageous in that it allows a direct measurement of a patient's ventricular pressure to be obtained.

A method and system incorporated into an IMD that detects changes in ventricular afterload using the morphology of a ventricular blood pressure wave. A peak positive pressure value Pb, peak positive and peak negative derivative pressures dP / dtPP and dP / dtNP, and a decreasing pressure Pc are determined. The sample times tb, at Pb, ta at dP / dtPP and tc at dP / dtNP are determined. An index alpha of the relative timing of peak positive pressure Pb in the blood ejection phase is calculated from, alpha=(tb-ta) / (tc-ta), the severity of ventricular afterload is proportional to the value alpha in the range between 0 and 1. The slope of the early ejection pressure in the blood ejection phase is calculated from beta=(Pc-Pb) / (tc-tb), wherein the severity of ventricular afterload is proportional to the magnitude of the index beta.

An implantable medical device has a pressure sensing arrangement to measure right ventricular pressure of a heart including a pressure sensor adapted to be positioned in the right ventricle of the heart, to measure the pressure and to generate a pressure signal in response to the measured pressure. The pressure sensing arrangement also has a pressure signal processor and a timing unit. The processor determines from the pressure signal, using diastolic timing signals from the timing unit based on the pressure signal identifying the diastolic phase, a diastolic pressure signal representing the ventricular pressure only during the diastolic phase of the heart cycle.

Embodiments of the invention provide a left ventricular assist device (LVAD) cannula that includes multiple independent sensors may help decrease the incidence of ventricular collapse and provide automatic speed control. A cannula may include two or more independent sensors. One sensor may measure ventricular pressure, while another may measure ventricular volume and / or ventricular wall location. With this information an automatic control system may be configured to adjust pump speed to minimize the likelihood of ventricular collapse and maximize LVAD flow in response to physiologic demand. Typically the volume sensors are conductance sensors. Further embodiments provide LVADs that are powered by RF energy.

Devices and methods are provided to treat acute and chronic heart failure by using one or more implantable or non-implantable sensors along with phrenic nerve stimulation to reduce intrathoracic pressure and thereby reduce pulmonary artery, atrial, and ventricular pressures leading to reduced complications and hospitalization.

A method and apparatus for pacing left and right ventricles of the heart involve measuring one or both of a right ventricular (RV) pressure and a left ventricular (LV) pressure, and computing a parameter developed from one or both of the RV and LV pressure measurements. The parameter is indicative of a degree of left and right ventricular synchronization. The parameter is assessed, and an interventricular (V-V) delay is adjusted in response to the parameter assessment. The V-V delay is adjusted to effect a change in the parameter that improves synchronization of the right and left ventricles. The computed parameter is a parameter indicative of hemodyamic state, such as a PP Loop or a pre-ejection period.

Techniques are provided for detecting left ventricular end diastolic pressure (LV EDP) using a pressure sensor implanted within the heart of a patient and for detecting and evaluating heart failure and pulmonary edema based on LV EDP. Briefly, the peak of the R-wave of an intracardiac electrogram (IEGM) is used to trigger the measurement of a pressure value within the left ventricle. This pressure value is deemed to be representative of LV EDP. In this manner, LV EDP is easily detected merely by measuring pressure at one point within the heartbeat—thereby eliminating any need to track ventricular pressure throughout the heartbeat. Techniques for detecting and evaluating heart failure and pulmonary edema based on the R-wave triggered LV EDP measurements are also set forth herein.

A pressure sensing device includes a body portion, a pressure transmitting port, and an electrical lead. The body portion includes transducing electronics within a housing that is shaped about a longitudinal axis. The housing has a coating thereon that promotes tissue growth to anchor the housing within a ventricular septum. The pressure transmitting port is located at a distal longitudinal end of the body portion such that a ventricle pressure being sensed is transmitted through the port and to the transducing electronics when the body portion is anchored in the ventricular septum. The electrical lead is connected to the transducing electronics and exits from a proximal longitudinal end of the body portion.

A medical device monitors a patient to predict worsening heart failure. An input circuit of the medical device receives a pressure signal representative of a pressure sensed within a ventricle of the patient's heart as a function of time. A processor derives from the pressure signal a ventricular pressure index for a ventricular contraction based upon pressures in the ventricle. The processor then provides an output based upon the ventricular pressure index.

A method and apparatus for pacing left and right ventricles of the heart involve measuring one or both of a right ventricular (RV) pressure and a left ventricular (LV) pressure, and computing a parameter developed from one or both of the RV and LV pressure measurements. The parameter is indicative of a degree of left and right ventricular synchronization. The parameter is assessed, and an interventricular (V-V) delay is adjusted in response to the parameter assessment. The V-V delay is adjusted to effect a change in the parameter that improves synchronization of the right and left ventricles. The computed parameter is a parameter indicative of hemodynamic state, such as a PP Loop or a pre-ejection period.

Techniques are provided for detecting left ventricular end diastolic pressure (LV EDP) using a pressure sensor implanted within the heart of a patient and for detecting and evaluating heart failure and pulmonary edema based on LV EDP. Briefly, the peak of the R-wave of an intracardiac electrogram (IEGM) is used to trigger the measurement of a pressure value within the left ventricle. This pressure value is deemed to be representative of LV EDP. In this manner, LV EDP is easily detected merely by measuring pressure at one point within the heartbeat—thereby eliminating any need to track ventricular pressure throughout the heartbeat. Techniques for detecting and evaluating heart failure and pulmonary edema based on the R-wave triggered LV EDP measurements are also set forth herein.

Described herein is a guide wire that includes one, two or multiple pressure transducers for use in TAVI. The guide wire may include an aortic pressure sensor spaced from a left ventricular pressure sensor with sufficient length to allow the aortic pressure sensor to be located in the aorta while the ventricular pressure sensor is simultaneously located in the left ventricle. The pressure readings between the left ventricle and aorta may be subtracted to determine an improved indication of the prognosis of a patient with intermediate post-TAVR aortic regurgitation after assessment with transesophageal echocardiography.

A system and method of determining hemodynamic parameters uses sensed ventricular blood pressure during a portion of ventricular pressure waveform following peak pressure. An estimated arterial diastolic pressure is based upon an amplitude of the sensed ventricular pressure corresponding to a time at which a first derivative of ventricular pressure as a function of time is at a minimum (dP / dtmin). Fill parameters such as isovolumetric relaxation constant, ventricular suction pressure, atrial kick pressure, and transvalve pressure gradient are derived from measured pressures representing minimum ventricular pressure, ventricular diastolic pressure, and diastasis pressure.

A medical device chronically monitors cardiac function in a patient. An input circuit of the medical device receives a pressure signal representative of a pressure sensed within a ventricle of the patient's heart as a function of time. A processor derives from the pressure signal a myocardial performance index based upon pressures in the ventricle. The processor then provides an output based upon the myocardial performance index.

The present invention provides a system and method for estimating a blood flow waveform contour from a pressure signal. An arterial or ventricular pressure signal is acquired from a pressure sensor. Landmark points are identified on the pressure waveform that correspond to features of a flow waveform. In one embodiment, the landmark pressure waveform points correspond to the onset of flow, the peak flow, and the end of the systolic ejection phase. The landmark pressure waveform points define a contour that approximates the flow contour. Beat-by-beat flow contour estimation can be performed to allow computation of flow-related hemodynamic parameters such as stroke volume or cardiac output for use in patient monitoring and / or therapy management.

Methods and devices for improving ventricular contractile status of a patient suitably exploit changes in ventricular pressure and / or dP / dtmax to provide and / or optimize a response to a patient. The ventricular pressure may be appropriately correlated to intracellular calcium regulation, which is indicative of contractile status. To assess ventricular contractile status, the device suitably observes a cardiac perturbation of the patient and measures force interval potentiation following the perturbation. The contractile potentiation can then be stored and / or quantified in the implantable medical device to determine the ventricular contractile status of the patient, and an appropriate response may be provided to the patient as a function of the ventricular contractile status. Examples of responses may include administration of drug or neuro therapies, modification of a pacing rate, or the like. Force interval potentiation may also be used to optimize or improve a parameter for a response provided by the implantable medical device.

The invention discloses a cardiac impulse assist system, which comprises a ventricular volume regulating device, a synchronizer and a control device, wherein the ventricular volume regulating device is used for regulating ventricular volumes; a sensor of the synchronizer is connected to the heart; the synchronizer is used for collecting ventricular systole signals; and the control device is used for receiving the ventricular systole signals collected by the synchronizer, and is used for controlling the ventricular volume regulating device to synchronously reduce the ventricular volumes when ventricular systole is performed. An automatic defibrillating device and a synchronous treatment device are arranged in the synchronizer; a defibrillating electrode of the automatic defibrillating device is connected to the heart; a pacing electrode of the synchronous treatment device is implanted into a chamber of the heart. As the ventricular volume regulating device is small in size, the cardiac impulse assist system disclosed by the invention can be implanted into the chamber of the heart. The cardiac impulse assist system disclosed by the invention can be used for completely imitating a ventricular pressure-volume change rule, can work synchronously with cardiac impulse, and can be used for assist the heart to pulsate and do work so as to treat cardiac failure, promote ventricular restoration and repair the perforation of ventricular septum.

In general, this disclosure describes techniques for monitoring ventricular capture of electrical stimulation based upon sensed ventricular pressures using an implantable medical device. One example method comprises obtaining a blood pressure signal for a first ventricle (e.g., right ventricle) of a patient, and determining whether stimulation captured a second, different ventricle (e.g., left ventricle) of the patient based upon the blood pressure signal for the first ventricle. Whether stimulation captured the second ventricle may be determined based on at least one value of a myocardial performance index that is determined based upon the blood pressure signal for the first ventricle. If a loss of capture is identified, the method may further comprise providing a warning signal and / or providing a therapy adjustment signal to adjust the electrical stimulation that is provided to the second ventricle.