Apparatus and method for measuring heart condition

Claim 1

In an apparatus for continuously measuring the endocardial viability ratio of a patient for use with sources providing electrical signals representing the patient's systemic arterial pressure and left atrial pressure, the improvements comprising in combination: a first input for a first signal varying as a function of the systemic arterial pressure and having a wave form with a leading edge at time t 0 , a dicrotic notch at time t 1 , and another leading edge at time t 2 ; a second input for a second signal varying as a function of the left atrial pressure; pulse generator means having said first signal as an input for generating a first pulse at times t 0 and t 2 and for generating a second pulse at a variable time after t 0 ; display means for displaying said first signal and said first and second pulses, said pulse generator means including means for adjusting the timing of said second pulse to occur at time t 1 ; an integrator having said first signal as an input; a switching circuit for connecting said second signal to said integrator as an input during the time period t 1 to t 2 in subtractive relation with said first signal; first and second sample and hold units; means for connecting said integrator output to said first sample and hold unit for the time period t 0 to t 1 ; means for connecting said integrator output to said second sample and hold unit for the time period t 1 to t 2 ; and dividing means having the output of said first and second sample and hold units as inputs for producing the ratio thereof as an output.