Calculate the Deceleration Time (DT) which is the time from the peak velocity of the E wave to the time where the deceleration slope of the E wave crosses the zero velocity scale. If the DT is < 150 msec then the PCWP is > 10. If the DT is > 150 msec then the PCWP is < 10 mmHg. A high PCWP will rapidly passively fill the left ventricle causing a sharp deceleration slope which will decrease the DT.
The difference of the PVIA wave duration and the LVIA wave duration will be reflected by the PCWP. A high LVEDP is reflected by a high LAP. A high LAP will, during atrial contraction, result in an increase in back flow in the pulmonary veins which increases the duration of the PVIA wave. A long PVIA wave, when compared to a LVIA wave duration results in a high PCWP calculation.