Method and apparatus for discrimination of ventricular tachycardia from supraventricular tachycardia and for treatment thereof

Claim 1

A cardioverter, comprising: treatment means for delivering a therapy to a patient's heart to treat ventricular tachycardia; means for sensing electrical signals from the ventricle of said patient's heart; detection means, coupled to said sensing means for detecting the occurrence of a depolarization of the ventricle of said patient's heart and for issuing an R-wave signal indicative thereof; digitizing means for converting said electrical signals from the ventricle of said patient's heart to digital signals indicative of the magnitude of said electrical signals and for storing said digital signals sequentially; windowing means responsive to said R-wave signal for defining a time window extending from a point in time prior to said R-wave signal until a point in time following said R-wave signal; and analysis means responsive to said R-wave signal for analyzing the said digital signals stored in the said time window defined in response to the occurrence of said R-wave signal, said analysis means in turn comprising: difference measuring means for sequentially scanning through the said digital signals stored during a said time window in a first direction and for measuring the difference between individual ones of said stored digital signals and others of said stored digital signals to determine whether said measured differences exceed a predetermined threshold; counting means for counting the number of sequential ones of said difference measurements exceeding said predetermined threshold and for generating an endpoint signal each time said number of said difference measurements exceeding said predetermined threshold reaches a predetermined count; width measurement means responsive to said counting means for measuring an interval between a first said endpoint signal to occur during said scanning and a last said endpoint signal to occur during said scanning to provide an R-wave width measurement; and ventricular tachycardia detection means responsive to said width measurement for detecting the occurrence of a ventricular tachycardia and for triggering delivery of said therapy.

Claim 7

A method of cardioversion, comprising: sensing electrical signals from a ventricle of a patient's heart; detecting the occurrence of a depolarization of the ventricle of said patient's heart; converting said electrical signals from the ventricle of said patient's heart to digital signals indicative of a magnitude of said electrical signals and storing said digital signals sequentially; defining a time window extending from a point in time prior to said detected depolarization until a point in time following said detected depolarization; and analyzing the said digital signals stored in the said time window, said analyzing step in turn comprising: sequentially scanning through the said digital signals stored during a said time window in a first direction and measuring the difference between individual ones of said stored digital signals and others of said stored digital signals to determine whether said measured differences exceed a predetermined threshold; counting the number of sequential ones of said difference measurements exceeding said predetermined threshold and defining an endpoint each time said number of said difference measurements exceeding said predetermined threshold reaches a predetermined count; measuring a time interval between a the first said endpoint to occur during said scanning and a last said endpoint to occur during said scanning to provide an R-wave width measurement; and detecting the occurrence of a ventricular tachycardia and triggering delivery of said therapy if said width measurement meets predetermined criteria.

Claim 8

A method of cardioversion, comprising: sensing electrical signals from a ventricle of a patient's heart; detecting the occurrence of a depolarization of the ventricle of said patient's heart; converting said electrical signals from the ventricle of said patient's heart to digital signals indicative of a magnitude of said electrical signals and storing said digital signals sequentially; defining a time window extending from a point in time prior to said detected depolarization until a point in time following said detected depolarization; and analyzing the said digital signals stored in the said time window, said analyzing step in turn comprising: sequentially scanning through the said digital signals stored during a said time window in a first direction and measuring the difference between individual ones of said stored digital signals and others of said stored digital signals to determine whether said measured differences exceed a predetermined threshold; counting the number of sequential ones of said difference measurements exceeding said predetermined threshold and defining an endpoint each time said number of said difference measurements exceeding said predetermined threshold reaches a predetermined count; measuring a time interval between a the first said endpoint to occur during said scanning and a last said endpoint to occur during said scanning to provide an R-wave width measurement; and detecting the occurrence of a ventricular tachycardia and triggering delivery of said therapy if said width measurement meets predetermined criteria.