Abstract: Techniques are provided for use with implantable medical devices such as pacemakers for optimizing interventricular (VV) pacing delays for use with cardiac resynchronization therapy (CRT). In one example, ventricular electrical depolarization events are detected within a patient in which the device is implanted. The onset of isovolumic ventricular mechanical contraction is also detected based on cardiomechanical signals detected by the device, such as cardiogenic impedance (Z) signals, S1 heart sounds or left atrial pressure (LAP) signals. Then, an electromechanical time delay (T_QtoVC) between ventricular electrical depolarization and the onset of isovolumic ventricular mechanical contraction is determined. VV pacing delays are set to minimize the time delay to the onset of isovolumic ventricular mechanical contraction. Various techniques for identifying the onset of isovolumic ventricular contraction based on Z, S1 or LAP or other cardiomechanical signals are described.

Abstract: Various techniques are provided for calibrating and estimating left atrial pressure (LAP) using an implantable medical device, based on impedance, admittance or conductance parameters measured within a patient. In one example, default conversion factors are exploited for converting the measured parameters to estimates of LAP. The default conversion factors are derived from populations of patients. In another example, a correlation between individual conversion factors is exploited to allow for more efficient calibration. In yet another example, differences in thoracic fluid states are exploited during calibration. In still yet another example, a multiple stage calibration procedure is described, wherein both invasive and noninvasive calibration techniques are exploited. In a still further example, a therapy control procedure is provided, which exploits day time and night time impedance/admittance measurements.

Abstract: Methods and systems to modulate timing intervals for pacing therapy are described. For each cardiac cycle, one or both of an atrioventricular (A-V) timing interval and an atrial (A-A) timing interval are modulated to oppose beat-to-beat ventricular (V-V) timing variability. Pacing therapy is delivered using the modulated timing intervals.

Abstract: Various techniques for delivering atrial pacing and supraventricular stimulation to achieve a desired ventricular rate and/or cardiac output are described. One example method described includes delivering a pacing signal configured to cause an atrial depolarization to a heart of a patient, wherein the atrial depolarization results in an associated refractory period during the cardiac cycle, and delivering a signal to a supraventricular portion of the heart of the patient subsequent to the atrial refractory period and during a ventricular refractory period of the cardiac cycle.

Abstract: A pacing output circuit can be configured to generate a ventricular pacing signal configured to be delivered to an electrode near the His bundle in a right ventricle of a heart to pace the right and left ventricles and improve synchronization of at least one of the ventricles relative to intrinsic activity. In an example, the ventricular pacing signal can include first and second signal components in opposite polarity from each other with respect to a reference component, the first and second signal components having substantially identical duration and magnitude.

Abstract: A cardiac stimulator is connected to a hemodynamic sensor to sense hemodynamic signals. An optimization module determines recommended AV and VV delays based on IEGM signals. A data processing module determines a delay control parameter for each preset AV delay and VV delay based on the collected hemodynamic signals for respective preset AV delay and VV delay, determines the AV delay setting that corresponds to the maximum delay control parameter and the VV delay setting that corresponds to the maximum delay control parameter, determines an AV delay error correction value as a difference between the AV delay corresponding to the maximum delay control parameter and a recommended AV delay, and determines a VV delay error correction value as a difference between the VV delay corresponding to the maximum delay control parameter and a recommended VV delay.

Abstract: The disclosure relates in some aspects to an implantable pressure sensor and a method of measuring pressure. In some embodiments pressure may be measured through the use of an implantable lead incorporating one or more pressure sensors. In some aspects a pressure sensor is implemented in a micro-electromechanical system (“MEMS”) that employs direct mechanical sensing. A biocompatible material is attached to one or more portions of the MEMS sensor to facilitate implant in a body of a patient. The MEMS sensor may thus be incorporated into an implantable lead for measuring blood pressure in, for example, one or more chambers of the patient's heart.

Abstract: A device and method for delivering electrical stimulation to the heart in order to improve cardiac function in heart failure patients. The stimulation is delivered as high-output pacing in which the stimulation is excitatory and also of sufficient energy to augment myocardial contractility. In order to provide a consistent hemodynamic response, the high-output pacing is optimized by delivering it using different parameter sets, evaluating the hemodynamic response thereto as reflected by one or more measured physiological variables, and selecting the parameter set with the best hemodynamic response.

Abstract: Various systems, methods and arrangements are implemented in connection with ventricular pacing. One such method relates to a method for use in connection with ventricular pacing of a left ventricle of a heart from a pacing lead located in the right ventricle. Ventricular function of the heart is sensed. The sensed ventricular function is used to determine whether a conduction abnormality exists. The ventricular pacing is provided in response to determining a conduction abnormality exists and the ventricular pacing is inhibited in response to determining a conduction abnormality does not exist.

Abstract: Electrical noise may be discriminated from sensed heart signals based on cardiovascular pressure. A plurality of detected cardiovascular pressure values are respectively associated with a plurality of detected tachyarrhythmia events. In some examples, a variance in the cardiovascular pressure, e.g., above a threshold range, may indicate that the detected tachyarrhythmia events are at least partially attributable to electrical noise. In some examples, stimulation therapy to a heart of a patient may be controlled based on the detection of a tachyarrhythmia episode and a variability in the cardiovascular pressure values that are associated with the tachyarrhythmia episode. In other examples, a sensing integrity indication may be generated upon determining that a tachyarrhythmia episode was associated with a variable cardiovascular pressure.

Abstract: Described herein are methods and apparatus for treating hypertension with electrical pre-excitation pacing therapy. Electrical pre-excitation of a hypertrophic region advances the timing of the regional contraction and reduces its contribution to the overall contraction. Such pre-excitation pacing therapy may be beneficial to hypertensive patients with an abnormal distribution of ventricular wall stress/strain.

Abstract: A method for treating patients after a myocardial infarction which includes pacing therapy is disclosed. A cardiac rhythm management device is configured to deliver pre-excitation pacing to one or more sites in proximity to an infarcted region of the ventricular myocardium. Such pacing acts to minimize the remodeling process to which the heart is especially vulnerable immediately after a myocardial infarction.

Abstract: A cardiac rhythm management (CRM) system includes a non-invasive hemodynamic sensing device and an implantable medical device to sense a hemodynamic signal and derive one or more cardiac performance parameters from the hemodynamic signal. The non-invasive hemodynamic sensing device includes at least a portion configured for external attachment to a body in which the implantable medical device is implanted. The one or more cardiac performance parameters are used for various diagnostic, monitoring, and therapy control purposes.

Abstract: A method and apparatus for treating or preventing neurocardiogenic syncope is disclosed. Upon detection of bradycardia or a drop in blood pressure indicating the onset of syncope, electrostimulation pulses are delivered during the heart's refractory period. The pulses are non-excitatory but increase myocardial contractility and thereby increase cardiac output.

Abstract: A method that electrically stimulates a heart muscle to alter the ejection profile of the heart, to control the mechanical function of the heart and reduce the observed blood pressure of the patient. The therapy may be invoked by an implantable blood pressure sensor associated with a pacemaker like device. In some cases, where a measured pretreatment blood pressure exceeds a treatment threshold, a patient's heart may be stimulated with an electrical stimulus timed relative to the patient's cardiac ejection cycle. This is done to cause dyssynchrony between at least two cardiac chambers, which alters the patient's cardiac ejection profile from a pretreatment cardiac ejection profile. This has the effect of reducing the patient's blood pressure from the measured pretreatment blood pressure.

Abstract: A method of monitoring pressure within a medical patient, includes measuring an actual pressure in a medical patient in a first time period; measuring an indicator of the actual pressure in the first time period, wherein the indicator is derived from an electrical signal of the patient's heart; determining a correlative relationship between the actual pressure and the indicator, wherein both the actual pressure and the indicator are obtained in the first time period; measuring the indicator in a second time period; and determining the actual pressure in the second time period based on the correlative relationship obtained in the first time period and the indicator obtained in the second time period.

Abstract: A method and device for delivering cardiac function therapy on a demand basis. An implantable device for delivering cardiac function therapy is programmed to suspend such therapy at periodic intervals or upon command from an external programmer. Measurements related to hemodynamic performance are then taken using one or more sensing modalities incorporated into the device. Based upon these measurements, the device uses a decision algorithm to determine whether further delivery of the cardiac function therapy is warranted.

Abstract: A method for treating patients after a myocardial infarction which includes pacing therapy is disclosed. A cardiac rhythm management device is configured to deliver pre-excitation pacing to one or more sites in proximity to an infarcted region of the ventricular myocardium. Such pacing acts to minimize the remodeling process to which the heart is especially vulnerable immediately after a myocardial infarction.

Abstract: A cardiac rhythm management (CRM) system includes a non-invasive hemodynamic sensing device and an implantable medical device to sense a hemodynamic signal and derive one or more cardiac performance parameters from the hemodynamic signal. The non-invasive hemodynamic sensing device includes at least a portion configured for external attachment to a body in which the implantable medical device is implanted. The one or more cardiac performance parameters are used for various diagnostic, monitoring, and therapy control purposes.

Abstract: Described herein are methods and apparatus for treating hypertension with electrical pre-excitation pacing therapy. Electrical pre-excitation of a hypertrophic region advances the timing of the regional contraction and reduces its contribution to the overall contraction. Such pre-excitation pacing therapy may be beneficial to hypertensive patients with an abnormal distribution of ventricular wall stress/strain.

Abstract: An example relates to a method for sensing a pulmonary artery pressure (PAP) and providing a sensed PAP signal, detecting an abnormal blood pressure (BP) condition using information from the sensed PAP signal, delivering a pacing energy to a heart, and automatically altering at least one pacing characteristic in response to the detected abnormal BP condition. The detecting an abnormal BP condition can include detecting various forms of hypertension or hypotension. The automatically altering the at least one pacing characteristic can include automatically altering at least one of a pacing rate, a pacing waveform, an atriventricular (AV) delay, an interventricular (VV) delay, a pacing mode, or a pacing site. The method can also include delivering vagal nerve stimulation and automatically altering the vagal nerve stimulation in response to the detected abnormal BP condition. The detecting the abnormal BP condition can also include using a sensed auxiliary physiological parameter.

Abstract: A method of monitoring physiological parameters for diagnosis and treatment of congestive heart failure in a patient. The method includes implanting at least one sensing device in a cavity of the patient's cardiovascular system, preferably so that the sensing device passes through and is anchored to a septum of the heart and, to minimize the risk of thrombogenicity, a larger portion of the sensing device is located in the right side of the heart and a smaller portion of the sensing device is located in the left side of the heart. Electromagnetic telecommunication and/or wireless powering of the sensing device is performed with an external readout device. The method can be used to perform effective monitoring, management, and tailoring of treatments for patients suffering from congestive heart failure, as well as many other diseases.

Abstract: In a shockwave system with a shockwave source for treatment of a patient with shockwaves, a control and evaluation unit for evaluating an input signal supplied directly thereto that is correlated with a blood pressure value of the patient determined during the treatment, and controls the shockwave source dependent on the input signal.

Abstract: A pacing system for providing optimal hemodynamic cardiac function for parameters such as ventricular synchrony or contractility (peak left ventricle pressure change during systole or LV+dp/dt), or stroke volume (aortic pulse pressure) using system for calculating atrio-ventricular delays for optimal timing of a ventricular pacing pulse. The system providing an option for near optimal pacing of multiple hemodynamic parameters. The system deriving the proper timing using electrical or mechanical events having a predictable relationship with an optimal ventricular pacing timing signal.

Abstract: A method and apparatus for optimizing and assessing the response to extra-systolic stimulation (ESS) are provided. An optimization/monitoring parameter is calculated as a function of potentiation ratio, PR, and recirculation fraction, RF, derived from measurements of myocardial contractile function during and after ESS. PR may be computed as the ratio of the contractile function on post-extra-systolic beats during ESS to baseline contractile function. RF may be computed as the slope of a linear regression performed on a plot of the contractile function for a post-extra-systolic beat versus the contractile function for the previous post-extra-systolic beat after ESS is ceased. The ESI resulting in a maximum optimization/monitoring parameter, preferably computed as the product of PR and RF, is determined as the optimal ESI. The operating ESI may be automatically adjusted, and/or PR and RF data may be stored for monitoring purposes.

Abstract: New decision paradigms for ICDs are described. In one implementation, an implantable system senses cardiac output and arterial pressure parameters and shocks the heart in inverse relation to the arterial pressure, if the cardiac output is insufficient. In another implementation, the implantable system applies atrial anti-tachycardia pacing before applying ventricular anti-tachycardia pacing, if the heart rate is tachycardic.

Abstract: A pacing system delivers cardiac protection pacing to protect the heart from injuries associated with ischemic events. The pacing system detects an ischemic event and, in response, initiates one or more cardiac protection pacing sequences each including alternative pacing and non-pacing periods. In one embodiment, the pacing system initiates cardiac protection pacing sequences including at least one postconditioning sequence to protect the heart from a detected ischemic event and a plurality prophylactic preconditioning sequences to protect the heart from probable future ischemic events.

Abstract: An external cardiac medical device for delivering Cardiac Potentiation Therapy (CPT). Techniques used with the device include initial diagnosis of the patient, delivery of the CPT, and configuration of the external device, so that CPT can be effectively and efficiently provided. In particular, these techniques include initially determining whether a patient should receive CPT, how to set the coupling interval for delivering CPT, how to configure the external medical device to deliver CPT stimulation pulses while not adversely affecting the device's ability to sense a patient's cardiac parameters and/or signals.

Abstract: Optimizing cardiac preload based on measured pulmonary artery pressure involves varying, for each repetition of an acute burst protocol, a parameter of pacing applied to a patient's heart during the acute burst protocol. Pulmonary artery pressure is measured during the repetitions of the acute burst protocol. The length of the repetitions is chosen so that the patient's baroreflex system does not adjust to the varied parameter of pacing during the repetitions of the acute burst protocol. An optimum ventricular preload is determined based on the measured pulmonary artery pressure. Pacing therapy is provided using a value of the parameter that is selected based on the determination of optimum ventricular preload.

Abstract: A system and method for administering a therapeutic treatment to the heart includes a pressure sensor positioned in the pulmonary artery, an implantable medical device located remotely from the sensor, and communication means for communicating pressure data from the pressure sensor to the implantable medical device. The system includes a control module operatively coupled to the implantable medical device. The control module is adapted for comparing the pulmonary arterial pressure data to a pre-programmed value, adjusting an operating parameter of the implantable medical device based on the relationship of the pulmonary arterial pressure to the pre-programmed value, and repeating this process until the relationship between the pulmonary arterial pressure data and the pre-programmed value is such that no adjustment is necessary.

Abstract: Various different implementations of lead systems are disclosed for use with implantable stimulation systems. Generally, the lead systems incorporate, within an elongate lead body, one or more electrical conduits that connect to one or more distal electrodes, and a liquid-filled pressure transmission catheter lumen that extends proximally from a distal entry port. Use of the lead systems allows accurate pressure sensing at a location near where the electrodes are positioned. In addition, a defibrillator lead is disclosed having such features, and a system using that lead is capable of directly monitoring pressure within a heart chamber, and using that information to confirm the delivery of a defibrillation pulse.

Abstract: A method for decreasing responsiveness or decreasing resistance to airflow of airways involves the transfer of energy to or from the airway walls to prevent or reduce airway constriction and other symptoms of lung diseases. The treatment reduces the ability of the airways to contract during an acute narrowing of the airways, reduces mucus plugging of the airways, and/or increases the airway diameter. The methods according to the present invention provide a longer duration and/or more effective treatment for lung diseases than currently used drug treatments, and obviate patient compliance issues.

Abstract: A medical device is provided that comprises a lead assembly configured to be at least partially located proximate to the heart. The lead assembly includes an extra-cardiac (EC) electrode to be positioned proximate to at least one of a superior vena cava (SVC) and a left ventricle (LV) of a heart. The lead assembly includes a subcutaneous remote-cardiac (RC) electrode configured to be located remote from the heart such that at least a portion of the greater vessels are interposed between the RC electrode and the EC electrode to establish an extra-cardiac impedance (ECI) vector. The processor module measures extra-cardiac impedance along the ECI vector to obtain ECI measurements. The processor module assesses a hemodynamic performance based on the ECI measurements.

Abstract: A pacing system for providing optimal hemodynamic cardiac function for parameters such as contractility (peak left ventricle pressure change during systole or LV+dp/dt), or stroke volume (aortic pulse pressure) using system for calculating atrio-ventricular delays for optimal timing of a ventricular pacing pulse. The system providing an option for near optimal pacing of multiple hemodynamic parameters. The system deriving the proper timing using electrical or mechanical events having a predictable relationship with an optimal ventricular pacing timing signal.

Abstract: Methods and devices for treating hypotension, such as in cases of shock, including septic shock and anaphylactic shock, wherein the treatment includes providing an electrical impulse to a selected region of the vagus nerve of a patient suffering from hypotension to block and/or modulate nerve signals that regulate blood pressure.

Abstract: Systems and methods include identifying a first portion and a second portion of a pulmonary artery pressure (PAP) signal during a cardiac cycle. A first timing interval between the first portion and the second portion is obtained and data related to the first timing interval is trended to provide a chronic physiological prognostic indicator. In an embodiment, a second timing interval is obtained from a third portion and a fourth portion of the PAP signal. Then, a function of the first and second timing intervals is trended to provide the chronic physiological prognostic indicator. In one instance, a ratio of the first interval to the second interval is calculated to provide an estimated right ventricle ejection fraction (RVEF) and the RVEF is trended.

Abstract: A method and device for delivering ventricular resynchronization pacing therapy in conjunction with electrical stimulation of nerves which alter the activity of the autonomic nervous system is disclosed. Such therapies may be delivered by an implantable device and are useful in preventing the deleterious ventricular remodeling which occurs as a result of a heart attack or heart failure. The device may perform an assessment of cardiac function in order to individually modulate the delivery of the two types of therapy.

Abstract: An aspect relates to an implantable medical device. An embodiment of the device comprises a pulse generator, sensor circuitry, a lead, and a controller. The pulse generator generates baroreflex stimulation pulses. The lead is adapted to be electrically connected to the pulse generator and to the sensor circuitry. The lead includes an electrode to distribute the baroreflex stimulation pulses to a baroreflex site and a pressure sensor to provide a signal indicative of blood pressure to the sensor circuitry. The controller is connected to the pulse generator and the sensor circuitry. The controller adapted to adjust the baroreflex stimulation pulses based on the blood pressure. Other aspects are provided herein.

Abstract: Methods and devices for treating hypotension, such as in cases of shock, including septic shock and anaphylactic shock, wherein the treatment includes providing an electrical impulse to a selected region of the vagus nerve of a patient suffering from hypotension to block and/or modulate nerve signals that regulate blood pressure.

Abstract: An implantable medical system includes a first die substrate with a first outer surface. The system also includes a second die substrate with a second outer surface. Furthermore, the system includes a medical device with a first portion that is mounted to the first die substrate and a second portion that is mounted to the second die substrate. The first and second die substrates are fixed to each other and substantially hermetically sealed to each other. Also, the medical device is substantially encapsulated between the first and second die substrates. The first portion is electrically connected to the second portion. Moreover, the first and second outer surfaces of the first and second die substrates are directly exposed to a biological material.

Abstract: A system and method for pacing rate control in a cardiac rhythm management (CRM) system. The method includes acquiring a pressure signal representative of coronary venous pressure (CVP) from a pressure sensor implanted within a coronary vein of the patient and generating a CVP waveform from the pressure signal. A pacing stimulus is applied to the patient's heart, and the pacing rate is increased in response to increases in patient's metabolic demand. The CVP index is monitored during the pacing rate increase, and the CRM system detects a reduction in the patient's hemodynamic performance based on the CVP index and establishes a maximum rate setting based on the pacing rate corresponding to the reduction in the patient's hemodynamic performance.

Abstract: A system and method for detecting and treating symptoms of early decompensation utilizing a cardiac rhythm management. The system applies an electrical stimulus to the patient's heart at a first set of pacing parameters including a lower rate limit (LRL) setting, and acquires a coronary venous pressure (CVP) signal from a pressure sensor implanted in a coronary vein of the patient. An average coronary venous end diastolic pressure (CV-EDP) value is calculated from the CVP signal. The system monitors the average CV-EDP value over a predetermined interval, and dynamically adjusts the LRL setting responsive to the detection of a first or a second predetermined event based on the average CV-EDP value.

Abstract: An aspect of the present subject matter relates to a system for providing baroreflex stimulation. An embodiment of the system comprises an adverse event detector to sense an adverse event and provide a signal indicative of the adverse event, and a baroreflex stimulator. The stimulator includes a pulse generator to provide a baroreflex stimulation signal adapted to provide a baroreflex therapy, and a modulator to receive the signal indicative of the adverse event and modulate the baroreflex stimulation signal based on the signal indicative of the adverse event to change the baroreflex therapy from a first baroreflex therapy to a second baroreflex therapy. Other aspects are provided herein.

Abstract: Various aspects of the present subject matter relate to a device. In various embodiments, the device comprises at least one port adapted to connect at least one lead, a CRM functions module connected to the port and adapted to provide at least one CRM function using the lead, a neural function module, and a controller connected to the CRM functions module and the neural function module. The at least one CRM function includes a function to provide an electrical signal to the lead to capture cardiac tissue. The neural function module includes a signal processing module connected to the port and adapted to receive and process a nerve traffic signal from the lead into a signal indicative of the nerve traffic. The controller is adapted to implement a CRM therapy based on the signal indicative of the nerve traffic. Other aspects are provided herein.

Abstract: A method and system for setting the operating parameters of a cardiac rhythm management device in which a plurality of parameter optimization algorithms are available. A measured feature of an electrophysiological signal such as QRS width has been shown to be useful in selecting among certain parameter optimization algorithms. In one embodiment, one or more resynchronization pacing parameters are set based on one or both of the feature extracted from an electrogram signal and the value of a resynchronization pacing parameter which tends to minimize the intrinsic atrial rate.

Abstract: A cardiac rhythm management (CRM) system includes an implantable medical device that delivers anti-tachyarrhythmia therapies including anti-tachyarrhythmia pacing (ATP) and a hemodynamic sensor that senses a hemodynamic signal. The implantable medical device includes a hemodynamic sensor-controlled closed-loop ATP system that uses the hemodynamic signal for ATP capture verification. When ATP pulses are delivered according to a selected ATP protocol to terminate a tachyarrhythmia episode, the implantable medical device performs the ATP capture verification by detecting an effective cardiac contraction from the hemodynamic signal. The ATP protocol is adjusted using an outcome of the ATP capture verification.

Abstract: For temporary cardiac pacing, non-bioelectrical monitoring of intracardiac blood pressure variations is provided in the right ventricle. Unlike traditional bioelectric sensing, which is accomplished via the pacing leads, pressure based sensing can be independently accomplished from anywhere within the volume of the right ventricle, making it unnecessary to force a stiff pacing electrode tip into the myocardium to ensure quality sensing. Consequently, the distal pacing electrode can be designed with a more bulbous tip to significantly reduce the risk of myocardial perforation during implant. An inflatable bladder, employed initially to guide the catheter into the right ventricle, is subsequently employed as a fluid pressure sensor bulb to transmit intracardiac blood pressure variations to a fluid pressure transducer integral within the pacing controller.

Abstract: Techniques are provided for estimating left atrial pressure (LAP) or other cardiac pressure parameters based on various parameters derived from impedance signals. In particular, effective LAP is estimated based on one or more of: electrical conductance values, cardiogenic pulse amplitudes, circadian rhythm pulse amplitudes, or signal morphology fractionation values, each derived from the impedance signals detected by the implantable device. Predetermined conversion factors stored within the device are used to convert the various parameters derived from the electrical impedance signal into LAP values or other appropriate cardiac pressure values. The conversion factors may be, for example, slope and baseline values derived during an initial calibration procedure performed by an external system, such as an external programmer. In some examples, the slope and baseline values may be periodically re-calibrated by the implantable device itself.

Abstract: Systems including an implantable receiver-stimulator and an implantable controller-transmitter are used for leadless electrical stimulation of body tissues. Cardiac pacing and arrhythmia control is accomplished with one or more implantable receiver-stimulators and an external or implantable controller-transmitter. Systems are implanted by testing external or implantable devices at different tissue sites, observing physiologic and device responses, and selecting sites with preferred performance for implanting the systems. In these systems, a controller-transmitter is activated at a remote tissue location to transmit/deliver acoustic energy through the body to a receiver-stimulator at a target tissue location. The receiver-stimulator converts the acoustic energy to electrical energy for electrical stimulation of the body tissue. The tissue locations(s) can be optimized by moving either or both of the controller-transmitter and the receiver-stimulator to determine the best patient and device responses.

Abstract: Techniques for determining when to deliver a pre-excitation signal to damaged cardiac tissue, e.g., infarct tissue, of a ventricle during cardiac pacing are described. A medical device detects an intrinsic or paced atrial depolarization, and then detects a subsequent mechanical event, e.g., contraction, in a ventricle. As examples, the mechanical event may be detected by measuring ventricular movement, or changes in intracardiac or systemic blood pressure. The medical device determines an interval between the atrial depolarization and the ventricular mechanical event, which may be referred to as an A-Vm interval. By subtracting a pre-excitation interval (PEI) from the A-Vm, the medical device determines an A-V interval between an atrial depolarization and delivery of the pre-excitation signal.