The late portion of a post myocardial infarct patient's QRS waveform contains a high frequency signal tail which is indicative of a tendency toward vertricular tachycardia. This invention digitally processes and filters a patient's QRS signals in a reverse time manner to isolate the high frequency tail...http://www.google.de/patents/US4422459?utm_source=gb-gplus-sharePatent US4422459 - Electrocardiographic means and method for detecting potential ventricular tachycardia
