Effect of varying differentiator frequency response on recorded peak dP/dt

The effects of varying the differentiator cutoff frequency on the recorded peak first derivative of left ventricular pressure were assessed. High fidelity, solid state pressure transducers and recording equipment were used. In the canine heart with a basic periodicity of 1-3 Hz, the differentiator frequency response required to record an accurate peak dP/dt is influenced by the value of peak dP/dt. In the range of peak dP/dt between 1 500 and 9 000 mm Hg/s (200 and 1 200 kPa/s), a differentiator cutoff frequency of at least 90 Hz was required to record accurately peak dP/dt.