Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Electrical therapeutic systems
Reexamination Certificate
2001-02-12
2003-07-22
Jastrzab, Jeffrey R. (Department: 3762)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Electrical therapeutic systems
C607S025000, C600S510000
Reexamination Certificate
active
06597952
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the field of methods and medical devices for modulating cardiac muscle activity and contractility and more specifically to methods and devices for setting the parameters of a detection time window used for initiating the delivery of excitable tissue controller (ETC) signals under a variety of conditions including varying heart rates, paced or sensed beats and the absence and presence of ETC signals' effects on the velocity of propagation of a cardiac depolarization wave.
BACKGROUND OF THE INVENTION
Excitable tissue controllers (ETCs) are devices which modulate the activity of excitable tissues by application of non-excitatory electrical stimulation to the excitable tissue through suitable electrodes in contact with the tissue. For example, ETC devices may be used, inter alia, to increase or decrease the contractility of cardiac muscle in vitro, in vivo and in situ., as disclosed in detail in PCT application, International Publication Number WO 97/25098 to Ben-Haim et al., titled “ELECTRICAL MUSCLE CONTROLLER”, incorporated herein by reference. Other methods and applications of ETC devices are disclosed in PCT applications commonly-assigned to the assignee of the present application, International Publication Number WO 98/10828, titled “APPARATUS AND METHOD FOR CONTROLLING THE CONTRACTILITY OF MUSCLES” to Ben Haim et al., incorporated herein by reference, International Publication Number WO 98/10829, titled “DRUG-DEVICE COMBINATION FOR CONTROLLING THE CONTRACTILITY OF MUSCLES” to Ben Haim et al., incorporated herein by reference and International Publication Number WO 98/10830, titled “FENCING OF CARDIAC MUSCLES” to Ben Haim et al., incorporated herein by reference, International Publications Number WO 98/10831 to Ben Haim et al., titled “CARDIAC OUTPUT CONTROLLER”, incorporated herein by reference.
Further applications of the ETC including devices combining cardiac pacing and cardiac contractility modulation are disclosed in PCT Application, International Publication No. WO 98/10832, titled “CARDIAC OUTPUT ENHANCED PACEMAKER” to Ben Haim et al., co-assigned to the assignee of the present application. Such ETC devices function by applying non-excitatory electrical field signals of suitable amplitude and waveform, appropriately timed with respect to the heart's intrinsic electrical activity to selected cardiac segments. The contraction of the selected segments can be modulated to increase or decrease the stroke volume of the heart. The timing of the ETC signals must be carefully controlled since application of the ETC signal to the myocardium at inappropriate times may be arrhythmogenic. The ETC signals must therefore be applied to the selected cardiac segment within a defined time interval during which the selected cardiac segment will not be stimulated by the ETC signals.
As disclosed in International Publication No. WO 98/10832, the ETC signals may be timed relative to a trigger signal which is also used as a pacing trigger, or may be timed relative to locally sensed electrogram signals.
U.S. patent application Ser. No. 09/276,460, to Mika et al., entitled “APPARATUS AND METHOD FOR TIMING THE DELIVERY OF NON-EXCITATORY ETC SIGNALS TO A HEART”, filed Mar. 25, 1999 and assigned to the common assignee of the present application, now U.S. Pat. No. 6,263,242, the entire specification of which is incorporated herein by reference, and the corresponding PCT international application PCT/IL00/00126, International Publication Number WO 00/57952, disclose a method for timing the delivery of non-excitatory ETC signals to a heart using, inter alia, an alert window period for reducing the probability of delivering an improperly timed ETC signal to the heart due to spurious detection of noise or ectopic beats.
The methods of timing of the delivery of ETC signals disclosed hereinabove do not take into account the fact that naturally occurring and pacemaker induced changes in heart rate (HR) may cause changes in the velocity of propagation of the depolarization wave in the myocardium. Additionally, the delivery of the ETC signals to the myocardium may also cause changes in the velocity of propagation of the depolarization wave in the myocardium. Other factors such as, inter alia, various cardio-active drug treatments and myocardial pathological conditions such as ischemia may also cause changes in the velocity of propagation of the depolarization wave in the myocardium. It is therefore desirable to have a method for determining proper timing of the delivery of ETC signals which takes into account variations in velocity of propagation of the depolarization wave in the myocardium under different cardiac conditions.
SUMMARY OF THE INVENTION
There is therefore provided, in accordance with a preferred embodiment of the present invention, a method for setting the parameters of an alert time window in an excitable tissue control device operative under a plurality of different cardiac conditions of a heart of a patient. The method includes the step of providing the excitable tissue control device with a set of data. The set of data includes a plurality of sets of alert time window parameters. Each set of alert time window parameters is associated with one of the plurality of different cardiac conditions. Each set of alert time window parameters includes at least a set of timing parameters usable for obtaining a beginning time point and an ending time point for the alert time window. Each set of the plurality of sets of alert time window parameters is obtained by processing data collected from a plurality of cardiac beats of the heart of the patient under the plurality of different cardiac conditions within a data collection session prior to the step of providing. The method further includes the step of automatically selecting, for a current beat cycle of the heart, a current set of alert time window parameters of the plurality of sets of alert time window parameters based on the current cardiac conditions detected for the current beat cycle. The method further includes the step of using, for the current beat cycle, the current set of alert time window parameters selected in the step of automatically selecting to start and terminate the alert time window based on the time of detecting a first depolarization event at or about a first cardiac site. The method further includes the steps of detecting, within the duration of the alert time window of the current beat cycle, a second depolarization event at a second cardiac site of the heart, and triggering the delivery of a delayed non-excitatory excitable tissue control signal at or about the second cardiac site based on the time of detection of the second depolarization event.
There is further provided, in accordance with a preferred embodiment of the present invention, a method for setting the parameters of an alert time window in an excitable tissue control device operative under a plurality of different cardiac conditions of a heart of a patient. The method includes the step of providing the excitable tissue control device with a set of data. The set of data includes a plurality of sets of alert time window parameters. Each set of alert time window parameters is uniquely associated with a different set of values of a plurality of cardiac condition defining parameters identifying one of the plurality of different cardiac conditions. Each set of alert time window parameters of the plurality of sets of alert time window parameters includes at least a set of timing parameters usable for obtaining a beginning time point and an ending time point for the alert time window. Each set of alert time window parameters is obtained by processing data collected from a plurality of cardiac beats of the heart of the patient under the plurality of different cardiac conditions within a data collection session prior to the step of providing. The method further includes the step of updating for a current beat cycle of the heart the values of a plurality of cardiac condition defining variables corr
Belsky Ziv
Mika Yuval
Prutchi David
Routh Andre G.
Impulse Dynamics N. V.
Jastrzab Jeffrey R.
Reed Smith LLP
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