System for the detection of cardiac events

A system for identifying a cardiac event in a human patient including:

• at least two electrodes implanted in the patient for obtaining the electrical signal from the patient's heart, the electrical signal being an electrogram;
• an implanted cardiosaver including
• (a) analog-to-digital converter circuitry for digitizing the electrogram to produce electrogram segments having a time duration that is at least 1 second;
• (b) memory means designed to store a baseline electrogram segment at a first predetermined time;
• (c) memory means designed to store a recently collected electrogram segment at a second predetermined time at a time that is later than the first predetermined time;
• (d) processor means coupled to said memory means for comparing the recently collected electrogram segment stored in the memory means at the second predetermined time with the baseline electrogram segment stored in the memory means at the first predetermined time;
• and,
• (e) means for identifying that the cardiac event has occurred when ST deviation of at least one beat of the recently collected electrogram segment shifts by more than a predetermined amplitude from the average ST deviation of at least two beats of the baseline electrogram segment.

A system for detecting a cardiac event from the electrogram of a patient's heart as measured by implantable electrodes, the system including:

• (a) electrical circuitry means for determining the time of occurrence of an R wave of the electrogram;
• (b) processor means for calculating the time period between successive R waves, that time period being called an R—R interval;
• (c) processor means for calculating the average signal amplitude of at least one sub-segment of the electrogram occurring within the R—R interval, the sub-segment having a start time and a time duration;
• (d) means for adjusting the start time and/or time duration of the sub-segment responsive to the calculated R—R interval;
• and,
• (e) processing means for detecting that the cardiac event has occurred by comparing the average signal amplitude of at least one sub-segment of at least one beat of the electrogram with a predetermined threshold amplitude.

A system for detecting a cardiac event from the electrogram of a patient's heart as measured by implantable and/or skin surface electrodes, the system including:

• (a) electrical circuitry means for determining the time of occurrence of an R wave of the electrogram;
• (b) processor means for calculating the time period between successive R waves, that time period being called an R—R interval;
• (c) processor means for calculating the average signal amplitude of the ST segment and the average signal amplitude of the PQ segment of the electrogram occurring within the R—R interval, the sub-segment having a start time and a time duration;
• (d) means for adjusting the start time and/or time duration of the ST segment responsive to the calculated R—R interval;
• (e) means for calculating an ST deviation by subtracting the average signal amplitude of the PQ segment from the average signal amplitude of the ST segment;
• and,
• (f) processing means for detecting that the cardiac event has occurred by comparing the amplitude of the ST deviation of at least one beat of the electrogram with a predetermined threshold amplitude.

A method for detecting that a cardiac event has occurred, the method including the following steps:

• (a) implanting at least two electrodes within a human subject at locations designed to pick up an electrical signal from a patient's heart, the electrical signal being an electrogram;
• (b) connecting the at least two electrodes to an implanted cardiosaver device that is designed to digitize the electrogram, the cardiosaver device also having electrical circuitry means for creating electrogram segments having a duration of at least 1 second;
• (c) using a physician's programmer to program the cardiosaver to process and store in memory baseline electrogram segments at specified times throughout each and every day;
• (d) programming specific times when the cardiosaver will collect, process and place in memory recent electrogram segments that occur after the baseline electrogram segment has been placed in memory;
• (e) programming the cardiosaver to detect that the cardiac event has occurred when the amplitude of the ST deviation of at least one beat of a recent electrogram segment shifts by more than a predetermined amplitude as compared with the average ST deviation of at least two beats of the baseline electrogram segment.

A system for the detection of a cardiac event of a human patient, the system including:

• (a) at least two electrodes implanted in the patient for obtaining an electrical signal from the patient's heart, the electrical signal being an electrogram;
• (b) analog-to-digital converter circuitry for digitizing the electrogram to produce electrogram segments having a time duration that is at least 1 second;
• (c) means for determining the time of occurrence of an R wave for each beat within an electrogram segment produced by the analog-to-digital conversion circuitry;
• (d) means for calculating an average heart rate of the electrogram segment;
• (e) processor means designed to detect that the cardiac event has occurred, the criteria for detection being dependent upon the average heart rate of the electrogram segment.

A system for detecting a cardiac event in a human patient the system including

• at least two electrodes attached to the patient's skin for obtaining the electrical signal from the patient's heart, the electrical signal being an electrocardiogram;
• a non-implanted cardiosaver including
• (a) analog-to-digital converter circuitry for digitizing the electrocardiogram to produce electrocardiogram segments having a time duration that is at least 1 second;
• (b) means for processing a first electrocardiogram segment at a first predetermined time to extract at least one baseline heart signal parameter of the patient;
• (c) memory means for storing the at least one baseline heart signal parameter;
• (d) means for processing a second electrocardiogram segment at a later, second predetermined time to extract at least one heart signal parameter of the patient;
• and,
• (e) processor means coupled to the memory means designed to detect the cardiac event when the at least one heart signal parameter extracted at the second predetermined time shifts by more than a predetermined threshold amplitude from the at least one baseline heart signal parameter extracted at the first predetermined time.

A system for identifying a cardiac event in a human patient including:

• at least two electrodes attached to the patient's skin for obtaining the electrical signal from the patient's heart, the electrical signal being an electrocardiogram;
• a non-implanted cardiosaver including
• (a) analog-to-digital converter circuitry for digitizing the electrocardiogram to produce electrocardiogram segments having a time duration that is at least 1 second;
• (b) memory means designed to store a baseline electrocardiogram segment at a first predetermined time;
• (c) memory means designed to store a recently collected electrocardiogram segment at a second predetermined time at a time that is later than the first predetermined time;
• (d) processor means coupled to said memory means for comparing the recently collected electrocardiogram segment stored in the memory means at the second predetermined time with the baseline electrocardiogram segment stored in the memory means at the first predetermined time;
• and,
• (e) means for identifying that the cardiac event has occurred when ST deviation of at least one beat of the recently collected electrocardiogram segment shifts by more than a predetermined amplitude from the average ST deviation of at least two beats of the baseline electrogram segment.

A system for the detection of a cardiac event of a human patient, the system including:

• (a) at least two electrodes attached to the patient's skin for obtaining an electrical signal from the patient's heart, the electrical signal being an electrocardiogram;
• (b) analog-to-digital converter circuitry for digitizing the electrocardiogram to produce electrocardiogram segments having a time duration that is at least 1 second;
• (c) means for determining the time of occurrence of an R wave for each beat within an electrocardiogram segment produced by the analog-to-digital conversion circuitry;
• (d) means for calculating an average heart rate of the electrocardiogram segment;
• (e) processor means designed to detect that the cardiac event has occurred, the criteria for detection being dependent upon the average heart rate of the electrocardiogram segment.