초록 ▼

A cardiac monitor is provided that monitors the condition of the heart of a cardiac patient and generates signals indicating one of several conditions, such as supraventricular tachycardia, ventricular tachycardia and ventricular fibrillation. In order to generate these signals, the ECG from the pat

A cardiac monitor is provided that monitors the condition of the heart of a cardiac patient and generates signals indicating one of several conditions, such as supraventricular tachycardia, ventricular tachycardia and ventricular fibrillation. In order to generate these signals, the ECG from the patient is analyzed to determine a cardiac interval and heart rate, as well as a waveform factor and a waveform factor irregularity. The waveform factor is derived from the average of the ECG amplitudes during a cardiac interval and the peak value of the ECG during the same interval. Preferably, a running average is calculated over several intervals. This waveform factor is then used to detect shockable ventricular arrhythmia. The waveform factor irregularity is indicative of the variability of the waveform factor and is used to differentiate between ventricular tachycardia and ventricular defibrillation.

대표청구항 ▼

1. A cardiac monitor for determining the cardiac condition of a patient comprising:a sensor that senses the intrinsic activity of a patient's heart and generates a corresponding sensed signal; an interval detector that detects an interval associated with a cardiac cycle based on said sensed signal;

1. A cardiac monitor for determining the cardiac condition of a patient comprising:a sensor that senses the intrinsic activity of a patient's heart and generates a corresponding sensed signal; an interval detector that detects an interval associated with a cardiac cycle based on said sensed signal; a waveform factor detector that detects a waveform factor from said sensed signal, said waveform factor being a function of a ratio of a mean value of said signal during said cardiac cycle and a peak value of said signal during said interval; and a first comparator that compares said waveform factor to a threshold and generates a corresponding for first output indicative of the patient's cardiac condition.