Method and apparatus for monitoring heart activity, detecting abnormalities, and cardioverting a malfunctioning heart

An apparatus for electronically monitoring the operation of a heart and for enabling the detection of abnormalities in cardiac function, the apparatus comprising:

• sensor means for sensing at least one cardiac parameter indicative of the operation of a heart being monitored;
• means for developing electrical signals representative of the sensed cardiac parameter;
• means for generating the probability density function of said electrical signals and;
• monitoring means for comparing the shape of the generated probability density function with the shape of a probability density function indicative of normal cardiac function;
• wherein differences in shape between the normal probability density function and the probability density function generated from the heart being monitored, indicate abnormal function of the heart being monitored.

An apparatus for sensing the operation of a heart and for cardioverting a heart experiencing certain abnormal cardiac functions, the apparatus comprising:

• sensor means for sensing ECG signals of a heart;
• operator means for operating on the sensed ECG signals and for developing at least two portions of a probability density function thereof;
• discriminator means for comparing the shape of the developed probability density function with the shape of a known probability density function, and for discriminating between normalcy of said developed probability density function and a developed probability density function which is indicative of the need for cardioversion;
• and means for discharging cardioverting energy into the heart upon the sensing of a need for cardioversion.

A two-stage apparatus for cardioverting a malfunctioning heart in such a manner that power is conserved, the apparatus comprising:

• first-stage detector means for discriminating between a normal cardiac state and a state requiring cardioversion;
• powering means for continually powering said first-stage detector means;
• second-stage detector means for further discriminating between a normal cardiac state and a state requiring cardioversion, normally in a stand-by condition and going to an active full power sensing condition upon initiation by said first-stage detector means;
• means for enabling said second-stage detector means and for thereby bringing said second-stage detector means from its stand-by condition to its full power active sensing condition;
• control means for powering said second-stage detector only upon said first-stage detector means sensing a cardiac state requiring cardioversion;
• delivery means for delivering cardioverting energy to the heart;
• and means for actuating said delivery means upon said second-stage detector means sensing a cardiac state requiring cardioversion.

An apparatus for cardioverting a needy heart, the apparatus comprising:

• sensor means for sensing the activity of a heart;
• means for generating electrical signals indicative of the R-to-R interval of said heart;
• phase lock loop circuitry for receiving and locking onto said electrical signals;
• sensing means for determining whether or not said phase lock loop circuitry has locked onto said electrical signals;
• delivery means for discharging cardioverting energy into said heart;
• means for issuing an enabling signal;
• and means for utilizing said enabling signal for initiating the discharge of cardioverting energy by said delivery means upon the sensing means determining the inability of said phase lock loop circuitry to lock onto said electrical signals.

A method for electronically monitoring and detecting abnormalities in cardiac function, the method comprising the steps of:

• sensing the electrical activity of a heart being monitored, and developing a cardiac parameter signal, such as an ECG, therefrom;
• operating on the cardiac parameter signal to develop at least two portions of a complete probability density function curve;
• deriving a measure of the shape of the probability density function curve by evaluating an indicator function based on measurements made on said portions of a complete probability density function curve;
• and monitoring the results of the indicator function by comparing the results to those derived from normal cardiac states to determine if the probability density function has a shape indicative of an abnormal cardiac state.

An apparatus for electronically monitoring and detecting abnormalities in cardiac function, the apparatus comprising:

• sensing means for sensing the electrical activity of a heart being monitored, and for developing a cardiac parameter signal, such as an ECG, therefrom;
• operating means for operating on the cardiac parameter signal to develop at least two portions of a complete probability density function curve;
• means for deriving a measure of the shape of the probability density function curve by evaluating an indicator function based on measurements made on said portions of a complete probability density function curve;
• and monitoring means for monitoring the results of the indicator function by comparing the results to those derived from normal cardiac states to determine if the probability density function has a shape indicative of an abnormal cardiac state.