Automatic external cardioverter/defibrillator with tachyarrhythmia detector using a modulation (amplitude and frequency) domain function

An external defibrillator for automatically generating a cardiac therapy for a person suffering from a life threatening cardiac condition, said external defibrillator comprising:

• a first electrode adapted to be attached to said patient to sense intrinsic cardiac signals from the patient;
• a modulation domain function detector coupled to said electrode to receive said cardiac signals and to generate a corresponding control parameter, said control parameter being generated to differentiate between ventricular arrhythmia and fibrillation, wherein said modulation domain function detector includes a first summer that sums samples from the intrinsic signals taken over a time period, a normalizer for normalizing said sum to compensate for amplitude variations of said intrinsic signals, said normalizer generating a normalized signal related to said parameter;
• a detector circuit coupled to said first electrode and adapted to detect a life threatening cardiac condition based on a physiological signal sensed through said electrode and said control parameter;
• a microprocessor-based controller coupled to said detector circuit and adapted to generate a command in the presence of said life threatening condition;
• and
• a pulse generator adapted to generate therapeutic pulses selected to terminate said life threatening cardiac condition in response to said command.

An external defibrillator that can be used to apply therapy to a patient, comprising:

• an electrode adapted to couple externally to the body of a patient;
• a sense circuit coupled to said electrode to sense a physiological signal indicative of an ECG complex of the patient;
• a cardiac arrhythmia detector coupled to said sense circuit to detect a life threatening cardiac arrhythmia based on said physiological signal;
• a modulation domain function detector that analyzes said physiological signal to detect its frequency and amplitude and generates a parameter indicative of a cardiac condition of the patient dependent on said frequency and amplitude;
• wherein said cardiac arrhythmia detector is arranged and constructed to generates serially samples of said physiological signal and said modulation domain function detector includes a summer which adds a predetermined number of said samples to generate a sum and a comparator adapted to compare said sum to a predetermined threshold, wherein said summer is arranged and constructed to generate a parameter related to a duration of said ECG complex;
• a microprocessor-based controller adapted to generate automatically a command in the presence of said cardiac arrhythmia and in accordance with said parameter;
• and
• a therapy delivery circuit adapted to deliver electrical therapy pulses to said patient to correct said cardiac arrhythmia in response to said command.

An external defibrillator that can be used to apply therapy to a patient, comprising:

• an electrode adapted to couple externally to the body of a patient;
• a sense circuit coupled to said electrode to sense a physiological signal indicative of an ECG complex of the patient;
• a cardiac arrhythmia detector coupled to said sense circuit to detect a life threatening cardiac arrhythmia based on said physiological signal;
• a modulation domain function detector that analyzes said physiological signal to detect its frequency and amplitude and generates a parameter indicative of a cardiac condition of the patient dependent on said frequency and amplitude;
• a microprocessor-based controller adapted to generate automatically a command in the presence of said cardiac arrhythmia and in accordance with said parameter;
• a therapy delivery circuit adapted to deliver electrical therapy pulses to said patient to correct said cardiac arrhythmia in response to said command;
• and
• a mode selector which can be activated by an attendant for selectively disabling said modulation domain function detector.

An external defibillator for automatically generating a cardiac therapy for a person suffering from a life threatening cardiac condition, said external defibrillator comprising:

• an electrode adapted to be attached to said patient to sense intrinsic cardiac signals from the patient;
• a modulation domain function detector coupled to said electrode to receive said cardiac signals and to generate a corresponding control parameter, said control parameter being generated to differentiate between ventricular arrhythmia and fibrillation, wherein said modulation domain function detector includes a modulation detector that determines the duration of a particular cardiac complex, said control parameter being a function of said duration;
• a detector circuit coupled to said first electrode and adapted to detect a life threatening cardiac condition based on a physiological signal sensed through said electrode and said control parameter;
• a microprocessor-based controller coupled to said detector circuit and adapted to generate a command in the presence of said life threatening condition;
• and
• a pulse generator adapted to generate therapeutic pulses selected to terminate said life threatening cardiac condition in response to said command.

An external defibrillator for automatically generating a cardiac therapy for a person suffering from a life threatening cardiac condition, said external defibrillator comprising:

• a first electrode adapted to be attached to said patient to sense intrinsic cardiac signals from the patient;
• a modulation domain function detector coupled to said electrode to receive said cardiac signals and to generate a corresponding control parameter, said control parameter being generated to differentiate between ventricular arrhythmia and fibrillation based on the amplitude and frequency of said intrinsic signals;
• a detector circuit coupled to said first electrode and adapted to detect a life threatening cardiac condition based on a physiological signal sensed through said electrode and said control parameter;
• a microprocessor-based controller coupled to said detector circuit and adapted to generate a command in the presence of said life threatening condition;
• a pulse generator adapted to generate therapeutic pulses selected to terminate said life threatening cardiac condition in response to said command;
• and
• an inhibit switch that may be used to inhibit the operation of said modulation domain function detector.