Comprehensive and Detailed Explanation From Exact Extract:

The left ventricular dP/dt is a measure of the rate of rise in left ventricular pressure during isovolumic contraction, which reflects systolic function. It is derived from Doppler echocardiography by measuring the time interval between mitral regurgitant jet velocities of 1 m/s and 3 m/s. Using the simplified Bernoulli equation, the pressure gradient at each velocity is calculated, and the rate of pressure rise (dP/dt) is calculated by dividing the pressure difference by the time interval between these velocities.

A normal left ventricular dP/dt is generally considered to be greater than 1200 mmHg/s. Values lower than this indicate impaired systolic function, as the ventricle is slower to generate pressure during contraction.

For example, a measured time interval of 36 milliseconds (0.036 seconds) between the MR velocities of 1 and 3 m/s corresponds to a dP/dt of approximately 889 mmHg/s, which is mildly reduced, indicating some systolic dysfunction.

The exact extract from the "Textbook of Clinical Echocardiography, 6e" states that normal dP/dt values are typically above 1000 mmHg/s, with >1200 mmHg/s considered a robust indicator of normal systolic function. This measure is useful but requires a measurable mitral regurgitation jet and consistent alignment of the ultrasound beam. Variability in measurement can occur based on technical factors, but the dP/dt remains a useful parameter to quantify systolic function noninvasively.