Abstract: The invention is directed to techniques for removing polarization artifacts from electrical activity signals in order to detect presence of an evoked response. More specifically, a medical device receives a signal that represents electrical activity within a heart of a patient following delivery of a stimulation pulse to the heart and reconfigures a filter state of a filter from an initial filter state to remove the polarization artifact from the electrical activity signal in order to determine whether a cardiac event, such as an evoked response has occurred. The medical device may, for example, when the filter of the medical device is a digital filter, recalculate the values of digital filter components using the present input value of the electrical activity signal as a direct current-(DC) input value of the digital filter.

Abstract: The invention is directed to techniques for synchronizing the internal clocks of two devices, such as an implantable medical device and an external device, with reduced reliance on periodic polling. In one embodiment, the invention is directed to a technique in which one of the devices computes a time drift. The time drift may occur because the internal clock of one device may run more slowly than the internal clock of the other device. One device may poll the other as a function of the time drift. In another embodiment, a system of medical devices synchronizes internal clocks to a time signal generated by a time reference.

Abstract: In general, the invention is directed towards techniques for adaptively prioritizing cardiac episode data in a memory of an implanted medical device (IMD). More specifically, the IMD receives new cardiac episode data, assigns each piece of data a priority value, and stores the data in a memory of the IMD. The IMD can further recalculate initial priority values assigned to stored cardiac episode data in response to subsequent cardiac episode data. In this manner, the prioritization scheme used by the IMD is adaptive, i.e., changes as more contextual information regarding the cardiac episode and subsequent cardiac episodes becomes available. Upon exceeding a memory capacity threshold, the IMD identifies the stored cardiac episode data with a lowest priority from the hierarchical priority relationship, and overwrites the identified portion of the stored cardiac episode data with the new cardiac episode data.

Abstract: An integrated device for remote monitoring of implanted medical devices and surface ECG information includes components for collection of information from an implanted medical device, collection of surface ECG information, and remote communication of the collected information to a remote monitoring station. The remote monitoring station controls operation of the integrated device to automatically acquire the information without substantial patient intervention. In this manner, the device promotes accurate and timely collection of the information, and reduced depletion of battery resources within the implanted medical device.

Abstract: In general, the invention is directed to techniques for detecting and addressing pacemaker syndrome. When a pacemaker detects a risk of pacemaker syndrome, the pacemaker paces one or more chambers of the heart to reduce the risk of pacemaker syndrome. One pacing technique is to apply ventricular paces, thereby reducing the delay between the atrial activation and the ventricular activation. Another technique, available to a patient who receives atrial pacing, is to decrease the atrial pacing rate.

Abstract: A cardiac therapy pulse delivery system includes a plurality of electrodes, an ECG signal processor circuit, and a pulse generator circuit. Each of the electrodes has at least one therapy element and at least one monitor element that are electrically insulated from one another. The ECG signal processor circuit is electrically coupled to each monitor element on each electrode and is operable to convert ECG signals detected by the monitor elements into ECG data. The cardiac pulse generator circuit is electrically coupled to each therapy element on each electrode and is operable to supply one or more cardiac therapy pulses thereto.

Abstract: In general, the invention is directed to techniques for delivery of pacing in response to a premature atrial contraction (PAC) to prevent atrial arrhythmia, i.e., delivery of post-PAC pacing pulses. The techniques may involve monitoring the success rate of prior post-PAC pacing sequences, and adjusting the number of post-PAC pacing pulses delivered subsequent post-PAC pacing sequences based on a success rate. In addition, the techniques may involve adjusting the post-PAC pacing interval based on the success rate.

Abstract: A cardiac stimulation device and method perform a diastolic function test during which an amplitude-based feature of an evoked response is determined for a number of AV or PV delay settings. Stimulation operating parameters may be adjusted in response to a detected change in diastolic function. The diastolic function test may be repeated periodically with results stored in memory for later downloading to an external device allowing a physician to monitor the diastolic response to a selected treatment.

Abstract: A cardiac rhythm management system recognizes patterns of interval durations, distinguishing between events in different heart chambers even though signals associated with those different heart chambers are processed using a commonly shared sensing circuit. A therapy delivery algorithm ignores intervals between cardiac events occurring in different heart chambers when determining a cardiac rate upon which the delivery of therapy is based. This reduces the risk of inappropriate delivery of therapy to the patient. Delayed conduction left ventricular beats are not erroneously recognized as a subsequent right ventricular beat, preventing such short intervals from inappropriately triggering a defibrillation countershock.

Abstract: As a safety feature for a cardiac rhythm management device in which a runaway protection feature may be disabled to allow programmed electrical stimulation and/or burst pacing to evaluate the device's ability to rein in an induced episode of tachycardia, a circuit is provided to automatically re-enable the runaway protection feature not only upon a software fault being detected, but also upon the lapse of a predetermined time interval.

Abstract: An implantable medical tissue stimulating device is designed to capture fault history relating to error events in a manner that allows subsequent analysis of operational performance prior to, during and subsequent to the occurrence of a detected error. Physiologic and operational data are fed through a buffer capable of temporarily storing such data over a predetermined interval. When a fault condition is detected, a trigger signal is generated a predetermined time following the occurrence of the fault condition and, upon generation of the trigger signal, the contents of the buffer are stored away in a RAM memory for subsequent read-out.

Abstract: A cardiac rhythm management system that includes a pacemaker configured for resynchronization pacing and an external programmer with an associated display for displaying electrogram markers. The markers are designed to relate information to a user in a manner suited for biventricular or other resynchronization pacing.

Abstract: Cardiac performance associated with a current set of N pacing parameters is improved by adjusting the cardiac pacing parameters until optimal or substantially optimal cardiac performance is achieved. The cardiac performance associated with the current set of N pacing parameters is determined. An incrementing step, a determining step, and a increment updating step, are repeated for i=1 to N, where i represents which of the N pacing parameter is being adjusted. The incrementing step includes incrementing an ith pacing parameter in the current set of N pacing parameters based on a corresponding ith increment value, to thereby produce an ith set of test pacing parameters. The determining step includes determining a cardiac performance associated with the ith set of test pacing parameters. The increment updating step includes updating the ith increment value based on the cardiac performance associated with the ith set of test pacing parameters.

Abstract: A method and apparatus for providing a therapy to the patient that includes a therapy component configured to provide the therapy to the patient, sensing circuitry sensing a parameter of the patient, and a microprocessor coupled to the therapy component and the sensing circuitry to determine onset of a first state of the patient in response to the sensed physiologic parameter, and to determine whether the onset of the first state is detected for a predetermined time period.

Abstract: In general, the invention is directed to techniques for capture testing of a capture threshold in cooperation with measurement of other cardiac parameters. Physiological or non-physiological parameters may indicate a possible change in the capture threshold, and a significant change in a cardiac parameter may trigger more frequent monitoring of the capture threshold. In addition, measurement of cardiac parameters in relation to measurement of the capture threshold may be useful in diagnosing problems and forecasting possible loss of capture.

Abstract: Transthoracic cardiac stimulation therapies provide for detection and treatment of cardiac asystole subsequent to delivery of a defibrillation therapy. A pacing therapy is transthoracicly delivered to terminate detected cardiac asystole using residual energy from a defibrillation energy storage source. The residual energy usable for the pacing therapy is sufficient to transthoracicly deliver at least one pacing pulse, and is typically sufficient to deliver a series of pacing pulses, prior to depletion of the defibrillation energy storage source. Detection of cardiac asystole is performed following delivery of each pacing pulse, and subcutaneous pacing support is terminated in response to detecting cardiac asystole termination.

Abstract: A system for monitoring trends in lead impedance includes collecting data from various sources in an implantable medical device system. Lead impedance, non-physiologic sensed events percentage of time in mode switch, results of capture management operation, sensed events, adversion pace counts, refractory sense counts and similar data are used to determine the status of a lead. A set of weighted sum rules are implemented by a software system to process the data and provide displayable information to health care professionals via a programmer. The lead monitoring system includes a patient alert system for patients to seek help in the event a serious lead condition is identified.

Abstract: A system and method is provided for reliably indicating that an implantable medical device is in need of replacement. The system and method measures the operational characteristics of the battery and the operational parameters of the implantable device itself. When these characteristics and parameters reach a defined level, the implantable medical device starts a replacement indicator timer. The replacement indicator timer starts and counts a replacement time period, with the replacement time period ending at a determined replacement date. The determined replacement date is the date at which the implantable medical device should be replaced.

Abstract: In an implantable medical device having an electrical lead coupled to tissue of a user and a circuit for measuring the impedance of the lead, a method and apparatus for responding to impedance variations in the lead which includes measuring the impedance of the lead while monitoring physiologic parameters of the user, detecting the presence or absence of electromagnetic interference, and if the impedance of the lead is out-of-range, determining whether the electromagnetic interference exceeds a predetermined value, and if the electromagnetic interference exceeds a predetermined value, administering a therapy to the tissue of the user.

Abstract: A system and method for automatically adjusting the gain for a shock lead system in an implantable medical device is provided. The system and method operate when, after a pre-selected period of time, the gain has not been programmed. The system and method then automatically produce and set the gain for the shock lead system. The system and method poll and determine a maximum value for the output of the shock lead system amplifier and produce a new gain value to scale the output to facilitate providing useful data that is large enough to separate signal from noise but small enough to avoid clipping.

Abstract: An implantable cardiac stimulation system capable of automatic capture verification is provided with an associated method for performing automatic testing functions using programmable, or automatically determined, atrioventricular delays. Automatic threshold testing and evoked response sensitivity testing performed at a user-specified delay setting, rather than a preset setting, allows assessment of automatic capture verification based on an atrioventricular delay relevant to daily system function. Further features of the present invention are an adjustable frequency with which automatic threshold tests are performed and an adjustable frequency with which threshold test results are stored in memory in a threshold record for better monitoring of lead stability or impending clinical problems. The frequency of performing threshold tests and the frequency of storing threshold test results may be varied according to the threshold stability.

Abstract: The present invention provides a method and system for detecting capture using pacing artifact cancellation. One or more pacing artifact templates are provided and a cardiac signal is sensed in a cardiac verification window. Each of the pacing artifact templates may characterize the pacing artifact associated with a particular pacing energy level, for example. A particular pacing artifact template is canceled from the cardiac signal. Capture is determined using the pacing artifact canceled cardiac signal. Detection of fusion/pseudofusion beats may be accomplished by comparing a cardiac signal to a captured response template.

Abstract: An active implantable medical device of the defibrillator, cardiovertor and/or antitachycardia pacemaker type having a high maximum frequency for antibradycardia stimulation. This device provides antibradycardia stimulation at a stimulation frequency that has a programmed maximum stimulation frequency. For a detected rate exceeding a given frequency threshold, the device analyzes the cardiac activity to discriminate a ventricular tachycardia or fibrillation to command in consequence an appropriate antitachycardia therapy. The maximum stimulation frequency for antibradycardia is higher than the given frequency threshold for the antitachycardia analysis, and the cardiac rhythm is analyzed to detect a particular succession of events that are likely to reveal the presence or the appearance of a ventricular tachycardia during such high antibradycardia stimulation.

Abstract: An implantable bi-ventricular heart stimulating device and system, suitable for treating congestive heart failure, have a control circuit with first and second pacing circuits and first and second sensing circuits. The device operates with time cycles corresponding to normal heart cycles. The control circuit determines: (a) whether a signal typical of an evoked response to a pacing pulse delivered by the first pacing circuit is sensed within a first time interval and (b) whether a signal typical for an R-wave transferred from the second ventricle, or from some other part of the heart, to the first ventricle is detected within a first time window. The operation of the device depends on whether the conditions (a) and (b) are fulfilled.

Abstract: The present invention provides a method and system for verifying capture in the heart. One or more pacing artifact templates characterizing a post pace artifact signal associated with a particular pace voltage or range of voltages are provided. A pacing artifact template is canceled from a cardiac signal sensed following a pacing pulse. Capture is detected by comparing the pacing artifact canceled cardiac signal to an evoked response reference. According to one aspect of the invention, the evoked response reference used to detect capture is an evoked response template. Capture is determined by comparing the evoked response template may be compared to the pacing artifact canceled cardiac signal. Fusion/pseudofusion detection may be determined by determining a correlation between a captured response template and a sensed cardiac signal.

Abstract: An active implantable medical device, such as a double chamber pacemaker or defibrillator or cardiovertor, having an improved adjustment of atrial sensitivity and of atrial stimulation energy. This device includes control algorithms for suspecting a loss of atrial detection and/or atrial capture that operates by analysis of a sequence of detected stimulations and ventricular and atrial detections.

Abstract: Response to cardiac resynchronization therapy is predicted for a given stimulation site so that an atrioventricular delay of an implantable device administering cardiac resynchronization therapy may be set to a proper amount. The first deflection of ventricular depolarization is measured, such as through a surface electrocardiogram or through an intracardiac electrogram measured by a lead positioned in the heart at the stimulation site. The maximum deflection of the ventricular depolarization is then measured by the lead positioned at the stimulation site. The interval of time between the first deflection and the maximum deflection of the ventricular depolarization is compared to a threshold to determine whether the stimulation site is a responder site. If the interval is larger than the threshold, then the site is a responder and the atrioventricular delay of the implantable device may be set to less than the intrinsic atrioventricular delay of the patient.

Abstract: A cardiac rhythm management system recognizes patterns of interval durations, distinguishing between events in different heart chambers even though signals associated with those different heart chambers are processed using a commonly shared sensing circuit. A therapy delivery algorithm ignores intervals between cardiac events occurring in different heart chambers when determining a cardiac rate upon which the delivery of therapy is based. This reduces the risk of inappropriate delivery of therapy to the patient. Delayed conduction left ventricular beats are not erroneously recognized as a subsequent right ventricular beat, preventing such short intervals from inappropriately triggering a defibrillation countershock. The system detects cardiac events, obtains a current interval between a current cardiac event and a previous cardiac event, and classifies the current interval into at least first and second categories, based on a duration of the current interval.

Abstract: An implantable medical device with internal processor is configured for diagnostic emulation with an external processor to enhance diagnostic testing with capabilities such as faster testing and more realistic testing. The implantable medical device can be a wide variety of implantable devices such as neuro stimulators, pacemakers, defibrillators, drug delivery pumps, diagnostic recorders, cochlear implants, and the like. The external processor is coupleable to the medical device to execute software involving medical device components with a bus switch coupled to the address bus, the data bus, and the internal processor. The bus switch has a bus switch external connector that when activated is configured to couple an external processor through the address bus external connection to the address bus and the external processor through the data bus external connector to the data bus.

Abstract: A heart stimulating device has a stimulation threshold measuring circuit for performing threshold searches by measuring a stimulation threshold value, a pulse generator for delivering stimulation pulses of variable amplitudes and duration, a control unit for controlling the pulse generator to deliver stimulation pulses of amplitudes related to the measured threshold value, an interval timer for initiating time-initiated threshold searches, wherein the time between consecutive time-initiated threshold searches is defined as a threshold search interval. The interval timer varies the threshold search interval, dependent on the result of at least the last performed threshold search.

Abstract: Systems and methods for determining the coronary sinus vein branch location of a left ventricle electrode are disclosed. The systems and methods involve detecting the occurrence of electrical events within the patient's heart including sensing one or more of the electrical events with the electrode and then analyzing the electrical events to determine the electrode's position. The determination of electrode position may be used to automatically adjust operating parameters of a VRT device. Furthermore, the determination of electrode position may be made in real-time during installation of the electrode and a visual indication of the electrode position may be provided on a display screen.

Abstract: In a cardiac stimulating device for biventricular stimulation, an intracorporeal ECG signal obtained from measuring electrode leads located outside of the heart is used for monitoring capture of the right and left ventricles. If loss of capture is detected in any of the ventricles then the pacing pulse energy will be adjusted to obtain complete biventricular capture.

Abstract: An implantable stimulation device and associated method allow for the selection of an inter-ventricular or inter-atrial delay which results in optimal hemodynamic benefit for the patient. The stimulation device monitors and measures the width of the QRS complex, or a P wave in response to different interpulse delays during biventricular or biatrial stimulation. The stimulation device then selects the optimal interpulse delay that results in the minimum QRS or P width. The present method allows for the adaptive adjustment of the interpulse interval over time, caused for example, by changes in disease state, medical therapy, physical activity or other factors may cause changes in the electromechanical response of the heart.

Abstract: A cardiac rhythm management apparatus may include a monitored energy source, a reference energy source, and a measurement module. The monitored source provides an initial pacing amplitude voltage and a pacing droop voltage, while the reference source provides a substantially fixed reference voltage. The measurement module, coupled to the monitored source and the reference source, provides a measurement related to the lead impedance associated with the rhythm management apparatus that is substantially independent of the reference voltage. Thus, a system may include the apparatus coupled to a lead wire. An article may cause a machine to implement a method which operates to determine a ratio of the actual initial pacing amplitude voltage to the actual pacing droop voltage.

Abstract: A cardiac pacing system and method incorporate DSP processing and software algorithms for collecting signal amplitude data and noise data, and organizing the data for automatic checking of signal channel gain and signal detection sensitivity. Unfiltered signals are used to obtain values representative of maximum amplitude, which values are stored in a gain histogram, from which determination of the percentage of clipped signals can be made. Gain is adjusted by limiting clipping to a predetermined range of allowed clipping, to optimize use of the DSP range. The signals, both P waves and R waves for a dual chamber system, are also processed by DSP and parameters representing maximum amplitudes are stored in amplitude histograms. At the same time, noise is analyzed for respective windows of time following each ventricular event, and noise amplitude data is stored in noise histograms.

Abstract: Methods and systems for providing an implantable medical device with a controlled diagnostic function adapted to convert from a monitoring mode to a therapeutic mode upon sensing an actionable cardiovascular event are disclosed. A preferred embodiment uses an interactive control module to selectively control a plurality of gated circuits that turn the sensing, therapeutic and communications functions of the device on and off to conserve battery power and extend the life of the device. Some embodiments of a system disclosed herein also can be configured as a component of an Advanced Patient Management System that helps better monitor, predict and manage chronic diseases.

Abstract: An active implantable medical device, such as a double chamber pacemaker or defibrillator or cardiovertor, having an improved adjustment of atrial sensitivity and of atrial stimulation energy. This device includes control algorithms for suspecting a loss of atrial detection and/or atrial capture that operates by analysis of a sequence of detected stimulations and ventricular and atrial detections.

Abstract: A cardiac pacing device and method for automatically selecting an optimal evoked response sensing vector based on an evaluation of the evoked response signal quality are provided. Electrode switching circuitry allows selection of multiple sensing electrode vectors. Capture detection circuitry provides capture and loss of capture signal characteristics determined during a pacing threshold search to be used in determining evoked response signal quality parameters. An optimal evoked response sensing vector is selected based on evoked response signal quality parameters meeting predetermined criteria for reliable evoked response sensing.

Abstract: Techniques for increase the accuracy of detection of atrial capture may involve determining a ventricular sensing window for ventricular senses associated with atrial test pulses based on observed ventricular senses. For example, an implanted medical device may deliver atrial test pulses to a patient at a time prior to respective atrial pacing pulses to evaluate atrial capture. The implanted medical device observes ventricular senses in response to the atrial test pulses. The implanted medical device may determine a point such as, for example, a midpoint of the ventricular sensing window for the ventricular senses and shift a midpoint of the default ventricular window to the determined midpoint. Further, the implanted medical device may measure patient parameters, such as heart rate and activity level, and determine a ventricular sensing window for ventricular senses associated with atrial test pulses based on the observed ventricular senses and measured patient parameters.

Abstract: A method and device provide for determining capture in multiple chambers of a patient's heart using an electrode inserted into a coronary vein of the patient's heart. The coronary vein electrode is positioned adjacent to multiple heart chambers and is responsive to cardiac signals originating in the multiple chambers. The coronary vein electrode may be coupled to a single sense amplifier to detect the cardiac signals. Pace pulses may be applied to multiple heart chambers simultaneously or according to a phased timing sequence. Cardiac signals responsive to the pace pulses sensed using the coronary vein electrode may be used to verify capture in the multiple chambers of the heart.

Abstract: A cardiac rhythm management apparatus and system may include a first contact to provide a connection signal, a second contact to sense a corresponding connection signal using a lead and an electrode coupled to the second contact, a measurement module capable of being communicatively coupled to the first and second contacts to measure a characteristic associated with the connection signal, a comparison module to determine whether the lead is of a preselected type, and an indicator module to indicate the comparison result. An article may cause a machine to implement a method which includes providing a connection signal from one contact, measuring a characteristic associated with a corresponding connection signal at another contact, and comparing the characteristic with a range of values to determine a comparison result. The method may also include indicating and recording the comparison result.

Abstract: An apparatus and method for appropriate selection of high energy shocking electrodes based on impedance measurements. In one example, an impedance measurement circuit measures the impedance between different sets of electrodes upon implant. The measured electrode impedance is compared to a predetermined impedance range to detect the presence of a high-energy shocking electrode. If a high-energy shocking electrode is present, a lead electrode status indicator is set. Based on the state of the lead electrode status indicator, a processor prevents or allows the use of various electrode combinations to deliver high energy therapy. Since the increase in automaticity allows the system to change the programmed therapy based on the status of the leads, patient safety is increased.

Abstract: A system for monitoring trends in lead impedance includes collecting data from various sources in an implantable medical device system. Lead impedance, non-physiologic sensed events percentage of time in mode switch, results of capture management operation, sensed events, adversion pace counts, refractory sense counts and similar data are used to determine the status of a lead. A set of weighted sum rules are implemented by a software system to process the data and provide displayable information to health care professionals via a programmer. The lead monitoring system includes a patient alert system for patients to seek help in the event a serious lead condition is identified.

Abstract: A data logging system and method in which an implantable medical device transmits logged data to an external data logging device with low energy potential signals. The implantable device generates potential signals modulated with digitally encoded data by operating a current source to cause corresponding electrical potentials that can be sensed at the skin surface by the external data logging device. The data logging device then demodulates the sensed potentials to derive the digital data and stores the data in a data logging storage medium.

Abstract: Methods are provided for conducting diagnostic or therapeutic medical or surgical procedures in a patient wherein, during the procedure, autonomous ventricular electrical conductivity and escape beats are reversibly and transiently suppressed to facilitate the procedure. Also provided are compositions which are capable of inducing ventricular asystole in a patient. The compositions may include an atrioventricular (AV) node blocker. In one embodiment, compositions including an AV node blocker and a &bgr;-blocker are provided, wherein the &bgr;-blocker is present in an amount sufficient to substantially reduce the amount of AV node blocker required to induce ventricular asystole in the patient. The compositions and methods may be used for inducing temporary ventricular asystole in a beating heart, and to facilitate the performance of a variety of techniques, including minimally invasive microsurgical techniques.

Abstract: An active implantable medical device such as a pacemaker, defibrillator or cardioverter, able to detect a fusion situation for improving a capture threshold determination. This device is able to deliver to the patient's heart stimulation pulses presenting a predetermined amplitude and a duration, and adjusting the amplitude of these pulses. The adjustment involves calibrating the pulse amplitude, and delivering a stimulation pulse at null or at a primarily null voltage, and measuring automatically the ventricular capture threshold, including detecting the presence or absence of a capture consecutive to a stimulation. The fusion situation is monitored and, in the event of detected fusion situation, used to invalidate the adjustment of the stimulation pulse amplitude. This operates by delivering a stimulation pulse at null or primarily null voltage, and determining the presence of a fusion situation in the event of a detection of a capture in response to a stimulation at null or at primarily null voltage.

Abstract: A cardiac pacemaker in which a variable safety margin with respect to a capture threshold is employed in delivering pacing pulses. The safety margin of a pacing pulse is made to vary in accordance with the pattern of preceding intrinsic and paced beats. The pacing pulse energy is thereby maintained at a more optimum value with respect to the capture threshold.

Abstract: Sensing artifacts in cardiac signals picked up by electrical leads are reduced by placing an electrical shunting switch across the conductors of the ECG sensing leads and the stimulation leads that deliver a subthreshold electrical stimulation. In addition, impedance switches are placed in series with the sensing leads. The shunting switches and impedance switches are then manipulated to present cardiac signals that can be analyzed for diagnostic purposes within less than 100 ms from delivery of a subthreshold electrical stimulation.

Abstract: Systems and methods for determining the coronary sinus vein branch location of a left ventricle electrode are disclosed. The systems and methods involve detecting the occurrence of electrical events within the patient's heart including sensing one or more of the electrical events with the electrode and then analyzing the electrical events to determine the electrode's position. The determination of electrode position may be used to automatically adjust operating parameters of a VRT device. Furthermore, the determination of electrode position may be made in real-time during installation of the electrode and a visual indication of the electrode position may be provided on a display screen.

Abstract: A cardiac rhythm management device includes a dual chamber pacemaker, especially designed for treating congestive heart failure by pacing a plurality of sites. The device incorporates a program microcontroller which is operative to adjust the pacing mode and inter-site delay of the pacemaker so as to achieve optimum hemodynamic performance. Atrial cycle lengths measured during transient (immediate) time intervals following a change in the mode inter-site delay are signal processed and a determination can then be made as to which particular configuration yields the optimum performance. Performance is optimized when the patient is at rest and when the patient exercises so that a rate-adapted dynamic value of the optimum performance can be applied.