Automated analysis of intracardiac blood pressure waveforms for implantable defibrillators

In implantable cardioverter defibrillators (ICDs) heart rate can not discriminate lethal tachycardias from benign ones which lead to false therapy. The blood pressure (BP) waveform is the clue for classifying these varieties. The authors have designed and developed an automated online analysis of BP waveforms and propose a possible method to detect tachycardias by examining BP waveforms only. The associated tachycardia algorithm that discerns the change of stroke volume output of the heart identified unstable tachycardias with a rate of 90.5% (specificity) and 67.6% (sensitivity). Detected tachycardias exhibited irregularities in interval and magnitude of BP waveforms. However, for tachycardias which were not detected there were regular BP waveforms although the magnitude and rate were different from that of sinus rhythm. It is concluded that this feature can be the clue for discrimination of hemodynamically stable and unstable tachycardias