Abstract: Method and apparatus for analyzing electrocardiogram signals to ascertain any defects or abnormalities in heart activity. Sensed, orthogonal x, y and z input signals are processed to obtain QRS onset and then passed through first and second spectral filters having respective passbands of 70-200 hertz and 40-200 hertz in order to establish QRS offset and accurate determinations of RMS voltage values and (LAS) low amplitude signals in the terminal QRS portion of the ECG signal. A spectral filtering of the x, y and z input signals with 150-250 hertz bandpass window also allows determination of certain high frequency activity in the midportions of the QRS.

Abstract: Method and apparatus for analyzing ECG signal data for diagnostic purposes by performing an incrementally moving, short window FFT analysis to produce a set of spectral templates representative of the spectral frequency content of the ECG at each window position. The spectral templates may be displayed as a representation of a three dimensional surface or mathematically analyzed. The changes in the shape of the templates or surface with time represent a change in the spectrum, which are shown to be an indication of abnormalities in the heart.

Abstract: A method and apparatus for examining the QRS complex of ECG signals to detect minute late potentials. The system functions to filter the QRS signals bi-directionally, and further separately processes the two filtered signals through selected window functions before summation. The summed signal is then passed through a smoothing function to produce an output signal of ideal phase that delineates any late potentials within the QRS complex.

Abstract: Method and apparatus for analyzing ECG signal data for diagnostic purposes by performing an incrementally moving, short window FFT analysis to produce a set of spectral templates representative of the spectral frequency content of the ECG at each window position. The spectral templates may be displayed as a representation of a three dimensional surface or mathematically analyzed. The changes in the shape of the templates or surface with time represent a change in the spectrum, which are shown to be an indication of abnormalities in the heart.

Abstract: An omnidirectional ultrasonic probe, having specific application for connection to the distal end of an esophageal catheter, includes a support member upon which are coaxially mounted a transmitter member, a receiver member, and one or more acoustic reflector members. The acoustic reflector member or members reflect transmissions and receptions of ultrasonic signals along substantially parallel paths. The reflector members also provide omnidirectional reflection. Separate transmitter and receiver members are used in the preferred embodiments to facilitate continuous wave operation.