Abstract: A method for assessing cardiac function suitable for incorporation into an implantable cardiac rhythm management device. By measuring daily exertion levels in accordance with the invention, an assessment of cardiac function can be made that has been found to correlate well with conventional clinical classifications. The invention also provides for assessing cardiac function in conjunction with different pacing schemes designed to treat heart failure and using the assessment to select the best such scheme for the patient.

Abstract: A cardiac rhythm management device includes a dual chamber pacemaker, especially designed for treating congestive heart failure. The device incorporates a program microcontroller which is operative to adjust the pacing site, AV delay and interventricular 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 site, AV delay and interventricular delay are signal processed and a determination can then be made as to which particular configuration yields the optimum performance. Paced transient beats following periods of baseline beats are synchronized to the patient's respiratory cycle to minimize effects of respiratory noise on atrial cycle length measurements.

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.

Abstract: The efficacy of a lesion produced between a pair of ablation electrodes is assessed by analyzing the time it takes for a pulse of energy to travel from one electrode to the other. During a first time period, a first pulse of energy is applied to a first electrode. The time it takes for the pulse to conduct through the tissue to a second electrode is determined. During a time period subsequent to the first time, a subsequent pulse of energy is applied to the first electrode and the time it takes for the subsequent pulse to conduct through the tissue to the second electrode is determined. Changes in the conduction times are monitored by calculating the difference between consecutive conduction times and comparing the difference to a preset value. If the difference is below the preset value the lesion is considered adequate.

Abstract: A first power output with a first frequency is provided to a first set of electrodes while a second power output with a second frequency, different then the first frequency, is provided to a second set of electrodes. Power outputs are provided to electrodes so adjacent electrodes receive power outputs with different frequencies, thereby establishing a voltage potential between adjacent electrodes and bipolar current flow. The frequencies of the power outputs are selected such that the resultant waveform indicative of the magnitude of the amplitude difference between the outputs has a period short enough to avoid stimulation of excitable muscular and cardiac tissue. Periodic frequency switching between the first and second power output provides uniform current flow between the electrodes over a given period of time. The addition of a backplate establishes unipolar current flow.

Abstract: A cardiac rhythm management device includes a dual chamber pacemaker, especially designed for treating congestive heart failure. The device incorporates a program microcontroller which is operative to adjust the pacing site, AV delay and interventricular 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 site, AV delay and interventricular delay are signal processed and a determination can then be made as to which particular configuration yields the optimum performance. Paced transient beats following periods of baseline beats are synchronized to the patient's respiratory cycle to minimize effects of respiratory noise on atrial cycle length measurements.

Abstract: A first power output with a first frequency is provided to a first set of electrodes while a second power output with a second frequency, different then the first frequency, is provided to a second set of electrodes. Power outputs are provided to electrodes so adjacent electrodes receive power outputs with different frequencies, thereby establishing a voltage potential between adjacent electrodes and bipolar current flow. The frequencies of the power outputs are selected such that the resultant waveform indicative of the magnitude of the amplitude difference between the outputs has a period short enough to avoid stimulation of excitable muscular and cardiac tissue. Periodic frequency switching between the first and second power output provides uniform current flow between the electrodes over a given period of time. The addition of a backplate establishes unipolar current flow.

Abstract: Power signals having controllable peak-to-peak amplitudes are provided to electrode sets so that during a first period of time, a first amplitude signal is provided to a first electrode set and a second amplitude signal is provided to a second electrode set. The first amplitude is greater than the second amplitude and bipolar current flows from the first electrode set to the second electrode set. During a second period of time, a third amplitude signal is provided to the first electrode set and a fourth amplitude signal is provided to the second electrode set. The third amplitude is less than the fourth amplitude and the current flows from the second electrode set to the first electrode set. Alternating first and second periods of time establish repetitive bipolar current flow between electrode sets. The addition of a backplate establishes unipolar current flow.

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.

Abstract: Power signals having controllable peak-to-peak amplitudes are provided to electrode sets so that during a first period of time, a first amplitude signal is provided to a first electrode set and a second amplitude signal is provided to a second electrode set. The first amplitude is greater than the second amplitude and bipolar current flows from the first electrode set to the second electrode set. During a second period of time, a third amplitude signal is provided to the first electrode set and a fourth amplitude signal is provided to the second electrode set. The third amplitude is less than the fourth amplitude and the current flows from the second electrode set to the first electrode set. Alternating first and second periods of time establish repetitive bipolar current flow between electrode sets. The addition of a backplate establishes unipolar current flow.

Abstract: A method of optimizing cardiac resynchronization therapy delay over a patient's full range of activity for use in operating an implantable cardiac pacing device and such a device are disclosed. The method includes measuring selected conduction time between selected sites in the heart for a plurality of beats and logging the values on a periodic repeating programmable basis to produce cumulative data and constructing a current template of conduction time in relation to one or more other sensed parameters of interest over a desired range of patient activity levels. The current template is used to derive suggested optimum pacing timing.

Abstract: An apparatus and method for assessing the status of well-being of patients being treated for CHF using cardiac pacing as a therapy. By sampling the output from an activity sensor or the like, and by noting the frequency with which the averaged rectified sensor output exceeds a preset threshold following changes in the pacing mode, the efficacy of the new mode compared to the previous one can be evaluated.

Abstract: The efficacy of a lesion produced between a pair of ablation electrodes is assessed by analyzing the time it takes for a pulse of energy to travel from one electrode to the other. During a first time period, a first pulse of energy is applied to a first electrode. The time it takes for the pulse to conduct through the tissue to a second electrode is determined. During a time period subsequent to the first time, a subsequent pulse of energy is applied to the first electrode and the time it takes for the subsequent pulse to conduct through the tissue to the second electrode is determined. Changes in the conduction times are monitored by calculating the difference between consecutive conduction times and comparing the difference to a preset value. If the difference is below the preset value the lesion is considered adequate.

Abstract: Based upon patient studies indices a high degree of correlation was found between HRV and VO2max, i.e., the patient's exercise capacity. Based on this finding, a pacing therapy optimization protocol for treating patients with CHF has been devised. The protocol involves first pacing the patient's heart with a pacemaker programmed to operate in a first mode for a predetermined time period and then collecting electrogram data from which a HRV index is derived. The mode is then changed and the steps repeated until all possible modes have been utilized. At that time, a determination is made as to which of the modes is associated with the largest HRV index and the pacemaker is then programmed to function in that mode. Alternatively, the method of the present invention can be applied to changes in drug therapy instead of or in combination with pacing therapy. By the plotting the HRV index computed in the manner described, the efficacy of a change in therapy on patient exercise capacity can be assessed.

Abstract: A method for assessing cardiac function suitable for incorporation into an implantable cardiac rhythm management device. By measuring daily exertion levels in accordance with the invention, an assessment of cardiac function can be made that has been found to correlate well with conventional clinical classifications. The invention also provides for assessing cardiac function in conjunction with different pacing schemes designed to treat heart failure and using the assessment to select the best such scheme for the patient.

Abstract: A method and system for operating a rate-adaptive pacemaker utilizing minute ventilation to measure exertion level. The method is applicable to heart failure patients who exhibit an oscillatory minute ventilation pattern.

Abstract: A method for estimating the efficiency of a patient's body, and specifically for estimating the efficiency of a patient's body while undergoing different cardiac therapies. Acceleration and heart rates of the patient are measured while undergoing various therapies. The acceleration—heart rate ratio for each therapy is calculated. The ratios for each therapy are compared and the therapy that has the highest acceleration—heart rate ratio is determined to be the most efficient. The most efficient therapy allows the patient to have the most acceleration with the lowest corresponding heart rate.

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.

Abstract: A method for assessing cardiac function suitable for incorporation into an implantable cardiac rhythm management device. By measuring daily exertion levels in accordance with the invention, an assessment of cardiac function can be made that has been found to correlate well with conventional clinical classifications. The invention also provides for assessing cardiac function in conjunction with different pacing schemes designed to treat heart failure and using the assessment to select the best such scheme for the patient.

Abstract: A method for assessing cardiac function suitable for incorporation into an implantable cardiac rhythm management device. By measuring daily exertion levels in accordance with the invention, an assessment of cardiac function can be made that has been found to correlate well with conventional clinical classifications. The invention also provides for assessing cardiac function in conjunction with different pacing schemes designed to treat heart failure and using the assessment to select the best such scheme for the patient.