System for and method of therapeutic stimulation of a patient's heart

A method of therapeutic stimulation of a patient's heart comprising:

• sensing blood pressure at a site in circulation system of a patient;
• comparing means sensed blood pressure at the site as determined over a period of predetermined duration with mean sensed blood pressure at the site as determined over a current period of given duration less than the duration of the period of predetermined duration to find if the determined mean blood pressures at the site differ by at least a predetermined amount;
• and
• controlling the escape interval or rate of a pacing system whenever the mean pressures differ by at least the predetermined amount.

A method of therapeutic stimulation of a patient's heart comprising:

• sensing blood pressure at a site in circulatory system of a patient;
• comparing means blood pressure at the site as determined over a period of predetermined duration with means blood pressure at the site as determined over a current period of given duration less than the duration of the period of predetermined duration to find if the determined means blood pressures at the site differ by at least a predetermined amount;
• sensing at least one physiological variable of the patient;
• and
• controlling the escape interval or rate of a pacing system contemporaneously based on the physiological variable and on the determined mean blood pressures at the site.

In a system for therapeutic stimulation of a patient's heart and which includes mean for producing pacing pulses and means for varying the escape interval or rate of a means for producing pacing pulses, an improvement comprising means for sensing blood pressure at a site in the circulatory system of a patient to produce an output, means responsive to the output from the sensing means for developing a variable first signal representative of mean blood pressure at the site over a period of predetermined duration, means responsive to the output from the sensing means for developing a variable second signal representative of mean blood pressure at the site over a period of given duration less than the period of predetermined duration, means responsive to the variable first signal and to the variable second signal for developing a stored first signal upon the first signal and the second signal differing by at least a predetermined amount, means responsive to the first signal and to the second signal for developing a first control signal whenever the stored first signal and the second signal differ by at least a given amount, means responsive to a signal dependent on at least one physiological variable for developing a second control signal, and means contemporaneously responsive to the first control signal and to the second control signal for conjointly controlling the means for producing pacing pulses for modifying the escape interval or rate thereof, whereby the escape interval or rate may be determined contemporaneously by the at least one physiological variable and by hemodynamic pressure at a site in the circulatory system.

A method of therapeutic stimulation of a patient's heart comprising:

• sensing blood pressure at a site in circulation system of a patient;
• comparing mean sensed blood pressure at the site as determined over a period of predetermined duration with mean sensed blood pressure at the site as determined over a current period of given duration less than the duration of the period of predetermined duration to find if the determined mean pressures at the site differ by at least a predetermined amount;
• storing a representation of the mean sensed blood pressure at the site as determined over a period of predetermined duration at the time the sensed mean blood pressures differed by at least the predetermined amount;
• comparing the stored representation of the sensed mean blood pressure with mean sensed blood pressure at the site as determined over a current period of the given duration to determine if current means blood pressure at the site differs from the stored representation by at least a give amount;
• and
• controlling the escape interval or rate of a pacing system whenever current mean blood pressure differs from the stored representation of mean blood pressure by at least the given amount.

A method of therapeutic stimulation of a patient's heart comprising:

• sensing blood pressure at a site in circulatory system of a patient;
• comparing means blood pressure at the site as determined over a period of predetermined duration with mean blood pressure at the site as determined over a current period of given duration less than the duration of the period of predetermined duration to find it the determined mean blood pressures at the site differ by at least a predetermined amount;
• storing a representation of the mean sensed blood pressure at the site as determined over a period of predetermined duration at the time the sensed mean blood pressures differed by at least the predetermined amount;
• comparing the stored representation of the sensed mean blood pressure with mean sensed blood pressure at the site as determined over a current period of the given duration to determine if current mean blood pressure at the site differs from the stored representation by at least a given amount;
• sensing at least one physiological variable of the patient;
• and
• controlling the escape interval or rate of a pacing system contemporaneously based on the physiological variable and determine the current mean pressure differing from the stored representation of mean pressure by at least the given amount.

In a system for therapeutic stimulation of a patient's heart and which includes means for varying escape interval or rate of a means for producing pacing pulses, an improvement comprising means for sensing hemodynamic pressure at a site in the circulatory system of a patient, means responsive to output from the sensing means for developing a variable first signal representative of mean pressure at the site over a period of predetermined duration, means responsive to output from the sensing means for developing a variable second signal representative of mean pressure at the site over a period of given duration less than the period of predetermined duration, means responsive to the variable first signal and to the variable second signal for developing a stored first variable signal upon the first variable signal and the second variable signal differing by at least a predetermined amount, means responsive to the first variable signal and to the second variable signal for developing a stored first variable signal upon the first variable signal and the second variable signal differing by at least a predetermined amount, means responsive to the first variable signal and to the second variable signal for developing a first control signal whenever the stored first variable signal and the second variable signal differ by at least a given amount, and means responsive to a signal dependent on at least one physiological variable for developing a second control signal, said means for varying escape interval or rate being contemporaneously responsive to the first control signal and to the second control signal for conjointly controlling the means for producing pacing pulses for modifying the escape interval or rate thereof;

• whereby the escape interval or rate may be determined contemporaneously by said at least one physiological variable and said hemodynamic pressure at a site in the circulatory system.