Abstract: A cardiac stimulation device and method deliver independent stimulation pulses to right and left cardiac chambers, based on the capture thresholds of each chamber, and confirm capture in each chamber. A threshold test is performed in one chamber while stimulating the opposite chamber at increased pulse energy and adjusted interchamber delay.

Abstract: The system and method discriminates P-waves or other electrical events originating in the atria from R-waves or other electrical events originating in the ventricles. In one example, far-field R-waves in the atria are distinguished from true P-waves using both a post-ventricular atrial blanking (PVAB) interval and a separate pre-ventricular blanking interval (pre-VAB) interval. Insofar as the pre-VAB interval is concerned, upon detection of a P-wave in the atria, the implantable medical device begins tracking a pre-VAB interval. If an R-wave is then detected in the ventricles during the pre-VAB interval, the P-wave is rejected as being a far-field R-wave. A PVAB interval may also be employed to filter out any P-waves detected in the atria immediately following detection of an R-wave in the ventricles. In another example, far-field R-waves are distinguished from true P-waves using template matching. P-waves detected in the atria are compared against a template representative of true P-waves.

Abstract: Systems and methods are provided for collecting enhanced diagnostic information specifically pertaining to overdrive pacing within an implantable cardiac stimulation device and for processing and displaying the enhanced diagnostic information using an external programmer. The enhanced diagnostic information includes one or more of overdrive pacing efficacy, overdrive pacing percentage, overdrive pacing/heart rate histogram data, longest recovery duration, atrial event data, minimum/maximum/average of the overdrive pacing rate, number of paced beats at maximum rate, duration of recovery time from maximum rate, intrinsic rate breakthrough histogram data, and number of rate increases. By tracking and displaying the enhanced diagnostic information, a physician can thereby more effectively and reliably program overdrive pacing control parameters to achieve optimal overdrive pacing performance.

Abstract: A multi-chamber stimulation device and associated method reliably and automatically distinguish fusion from loss of capture during ventricular stimulation. The stimulation device provides immediate and accurate fusion detection when a loss of capture is suspected in the ventricles without delivering back-up stimulation pulses. To achieve this objective, the far-field signal present in the atrial channel is examined for evidence of a far-field R-wave whenever the ventricular channel detects a loss of capture. If a far-field R-wave is present, fusion is confirmed, and a far-field R-wave is absent, loss of capture is confirmed. Additionally, the stimulation device inhibits unnecessary back-up stimulation and threshold tests when fusion occurs, and provides appropriate adjustment of stimulation parameters based on confirmed fusion detection such that fusion re-occurrence is minimized.

Abstract: Dynamic overdrive pacing adjustment techniques are described for use in implantable cardiac stimulation devices. In a first technique, an overdrive pacing unit of a microcontroller of the implantable device operates to optimize various control parameters that affect overdrive pacing so as to achieve a desired degree of overdrive pacing for the particular patient in which the stimulation device is implanted. Parameters to be optimized include the number of overdrive beats paced once overdrive pacing is trigged, the overdrive pacing response function, the recovery rate, and various base rates. The control parameters are adjusted in a hierarchical order of priority until the desired degree of overdrive pacing is achieved. Adjustment of the number of overdrive beats, the recovery rate, and various base rates is iteratively performed by using incremental numerical adjustments.

Abstract: An implantable cardiac stimulation device and method provide a histogram for storing the number of primary and backup stimulation pulses delivered at each amplitude setting, to monitor the performance of the automatic capture verification. The stimulation device delivers cardiac stimulation therapy in which a stimulation histogram advantageously stores the number of primary pulses delivered at each stimulation output, or range of outputs, and separately stores the number of high-energy backup stimulation pulses delivered. Knowing the historical frequency of the applied stimulation amplitudes is useful to a physician in selecting future stimulation pulse output settings and the working margin. This information is also useful in determining the expected remaining battery life. The stimulation histogram further provides a useful diagnostic tool for evaluating the integrity of the stimulation device, lead system and performance of the automatic capture algorithm.

Abstract: The stimulation device blanks T-waves from the atrial channel of an electrical cardiac signal by employing a T-wave blanking interval localized to the expected location and duration of the T-wave. To this end, the stimulation device determines the average interval between an R-wave and a T-wave in the patient in which the device is implanted and also determines the average duration of a T-waves within the patient. A T-wave blanking interval is initiated following the average R-T interval subsequent to detection of an R-wave and lasts for a period of time equal to the average T-wave duration. In this manner, highly localized T-wave blanking is achieved permitting P-waves or other atrial signals to be detected during remaining non-blanked portions of the atrial channel of the cardiac signal at least for the purposes of atrial rate detection. The relatively short T-wave blanking interval of the invention is particularly well suited for use in combipolar sensing systems.

Abstract: An implantable cardiac stimulation device, such as a pacemaker or Implantable Cardioverter Defibrillator, is configured to automatically monitor the effects of antiarrhythmic drugs on cardiac electrical signals within a patient to verify the efficacy of the drugs taken. In one example, an analysis of patient cardiac electrical signals is performed by comparing the cardiac electrical signals with values representative of the effects of different classes of antiarrhythmic drugs. If the implantable device determines that the prescribed antiarrhythmic drugs have not been effective, a warning signal is generated. The warning signal is conveyed directly to the patient via a bedside monitor and to the patient's physician via remote connection to an external programmer device so that both are notified of the drug efficacy problems.

Abstract: Techniques are described for overdrive pacing the heart using a pacemaker wherein the overdrive pacing rate only increases when at least two intrinsic beats are detected within a determined search period. In one specific technique, an increase in the pacing rate occurs only if two P-waves are detected within X cardiac cycles. In another specific technique, the overdrive pacing rate is increased only if at least two P-waves are detected within a block of N cardiac cycles. In both techniques, the overdrive pacing rate is decreased if no increase has occurred in the last Z cardiac cycles. By increasing the overdrive pacing rate only in response to detection of at least two P-waves within a determined number of cardiac cycles, an excessively high overdrive pacing rate is avoided. Other techniques are described for adaptively adjusting overdrive pacing parameters so as to achieve a determined target degree of pacing of, for example, 95% paced beats.

Abstract: An exemplary method for treating sleep apnea is described that includes determining parameters for a cardiac pacing pulse based, at least in part, on information characteristic of sleep apnea, wherein the cardiac pacing pulse aims to create a hemodynamic imbalance. An exemplary implantable cardiac device is programmable to perform such an exemplary method. Other exemplary methods, devices, and/or media are also disclosed.

Abstract: An implantable cardiac stimulation device applies pacing stimulation pulses to a heart and senses evoked responses to the pacing stimulation pulses. A pulse generator applies the stimulation pacing pulses to the heart in accordance with a pacing configuration. A sensor control selects an evoked response sensing electrode configuration from among a plurality of evoked response sensing electrode configurations in response to the pacing configuration. A sensor is then programmed to sense the evoked responses with the selected evoked response sensing electrode configuration. In accordance with a preferred embodiment, signal-to-noise ratios obtained with the various electrode configurations are used to select a best electrode configuration for sensing evoked responses.

Abstract: Techniques are provided for detecting natural electrical coherence within the heart and for administering or adjusting therapy based upon whether natural electrical coherence is detected. In one example, an implantable cardioverter defibrillator (ICD), upon detecting atrial fibrillation, delays administering an atrial defibrillation pulse until a period of natural electrical coherence is detected between the left and the right atria of the heart. The ICD may further delay the pulse until the ventricles of the heart are refractory so as to help prevent triggering ventricular fibrillation. The pulses are administered at a time selected based upon the period of electrical coherence to reduce the amount of electrical energy required within the pulse to reliably defibrillate the heart. Other types of therapy besides defibrillation therapy such as anti-tachycardia pacing pulses may also be timed based upon detection periods of natural electrical coherence. Method and apparatus embodiments are described.

Abstract: A splittable occlusion balloon sheath includes a splittable sheath onto which an occlusion balloon has been secured near the distal end of the splittable sheath. A splittable hemostasis valve or a partitioned hemostasis valve system may also be secured within or to the splittable occlusion balloon sheath. This splittable occlusion balloon sheath is utilized to introduce a medical device, such as electrode leads, into the coronary sinus of the human heart. A dilator may also be used with the splittable occlusion balloon sheath for introduction of the medical devices. The splittable occlusion balloon sheath and/or the dilator may be precurved with a particular shape to assist in the introduction of the splittable occlusion balloon sheath and/or dilator into the coronary sinus. Also disclosed is a process of use of the splittable occlusion balloon system within the coronary sinus.

Abstract: A system and method, for use in an implantable cardiac stimulation device, monitors progression or regression in heart disease such as congestive heart failure. The system includes a sensing circuit that derives an electrogram signal indicative of the electrical activity of the patient's heart. A processor processes the electrogram signal to determine interchamber conduction delays which are then stored in memory. The stored interchamber conduction delays may be later retrieved by way of a telemetry circuit. Relative changes in the interchamber conduction delays, over time, are indicative of progression or regression in the heart disease. The relative changes in the interchamber conduction delays may be further used to automatically adjust pacing parameters of the implantable cardiac stimulation device.

Abstract: An implantable cardiac stimulation device and associated method perform an automatic calibration procedure for evaluating whether automatic capture verification can be recommended. The calibration procedure calculates and displays a number of variables for use by a medical practitioner in programming automatic capture operating parameters. An average paced depolarization integral (PDI) is determined from the cardiac signals following delivery of multiple stimulation pulse below and above capture threshold such that both pure lead polarization signals and evoked response signals may be analyzed. From the paced depolarization integral data, a capture threshold, a stimulation response curve, a minimum evoked response, a maximum lead polarization, an evoked response sensitivity, an evoked response safety margin, and a polarization safety margin are determined. Based on these variables, the calibration procedure determines if automatic capture verification can be recommended.

Abstract: The stimulation device blanks T-waves from the atrial channel of an electrical cardiac signal by employing a T-wave blanking interval localized to the expected location and duration of the T-wave. To this end, the stimulation device determines the average interval between an R-wave and a T-wave in the patient in which the device is implanted and also determines the average duration of a T-wave within the patient. A T-wave blanking interval is initiated following the average R-T interval subsequent to detection of an R-wave and lasts for a period of time equal to the average T-wave duration. In this manner, highly localized T-wave blanking is achieved permitting P-waves or other atrial signals to be detected during remaining non-blanked portions of the atrial channel of the cardiac signal at least for the purposes of atrial rate detection. The relatively short T-wave blanking interval of the invention is particularly well suited for use in combipolar sensing systems.

Abstract: An implantable cardiac stimulation device, e.g., a pacemaker or an implantable cardioverter defibrillator (ICD), is provided which prolongs the atrial refractoriness of a heart. The implantable cardiac stimulation device includes a generator that delivers pacing pulses to an atrium of a heart and a detector that detects atrial activations of the heart. An inhibitor is coupled to the detector that inhibits the generator when an atrial activation is detected within an escape interval. A generator control coupled to the generator causes the generator to deliver a primary pacing pulse to the atrium at the end of the escape interval, absent an atrial activation being detected within the escape interval, and causes the generator to deliver a secondary pacing pulse to the atrium a delay time after an atrial activation is detected within the escape interval or the delivery of a primary pacing pulse to the atrium.

Abstract: An implantable cardiac device is programmed to monitor short term activity changes that occur while a patient is at rest to produce a sleep disturbance metric that is useful in analyzing and/or treating sleep apnea. After the implantable cardiac device confirms that a patient is at rest, the device monitors an instantaneous signal from an activity sensor to detect variances from normal rest mode activity. When the variances exceed a preset threshold for a short time period (e.g., less than 30-40 sec.), the patient is presumed to be experiencing a form of sleep disturbance as opposed to conscious or wakeful activity. These short term events are recorded as sleep disturbance events. The sleep disturbance metric are reported to a physician as a diagnostic to help ascertain the severity of sleep apnea or to evaluate the effectiveness of pacing therapies being applied to treat sleep apnea.

Abstract: An implantable cardiac stimulation system and method provides an external display of a heart activity signal sensed internally by an implantable cardiac stimulation device which has the appearance of a surface EKG. The heart activity signal is sensed by the implanted device and is processed by the device or the external display to have frequency characteristics resembling that of a surface EKG. The heart activity signal to be displayed takes the form of an intracardiac electrogram signal with a low frequency roll-on of no greater than 0.4 Hz and a high frequency cutoff of no less than 20 Hz. This provides a heart activity signal for display which has the appearance and most attributes of a surface EKG.

Abstract: A pacemaker or other implantable cardiac stimulation device is configured with both a rate hysteresis mode and a vasovagal syncope prevention mode. Within the rate hysteresis mode, the pacemaker detects when the intrinsic heart rate of the patient is below an escape rate, then paces the heart at a Base Rate until an intrinsic beat is detected. When programmed in the vasovagal syncope prevention mode, upon detecting the intrinsic rate falling below the Hysteresis Escape Rate, the pacemaker paces the heart at a Vasovagal Syncope Response Rate, which is considerably higher than the Base Rate. The pacemaker is preferably set to the syncope prevention mode for patients prone to recurrent vasovagal syncope. By pacing the heart at the higher Vasovagal Syncope Response Rate, the pacemaker thereby helps prevent a significant drop in blood pressure which might otherwise cause a loss of consciousness in the patient. System and method embodiments are described.