Dr.S.Venkatesan MD

Pulmonary valve should open shortly after the onset of RV systole , when RV pressure exceeds the PA end diastolic pressure which  will  be around 10-15 mmHg.

We know  cardiac valves open and close with reference to the pressure difference across the valve .So, in any part of cardiac cycle , if RV pressure exceeds  the pulmonary  arterial pressure , pulmonary valve is bound to open. (The pulmonary  leaflets simply doesn’t bother whether  RV is in systole or diastole )

What are the situations RV pressure may exceed PA pressure during diastole ?

Yes, if  RVEDP raises for any reasons beyond 15 mmhg it can prematurely open the pulmonary valve in late diastole. This often coincides with right atrial  contraction  that make the   RVEDP to spike  just before systole.  In chronic right heart dysfunction  the premature opening can occur  much earlier in diastole and not dependent on RA contraction. It can even be noted with AF if the mean RVEDP exceeds PA pressures.

This typically happen in constrictive pericardits and any  isolated RV failure  without pulmonary hypertension.(Please note , for premature  pulmonary valve opening to occur  one important prerequisite is,  PA pressure should be normal or low and hence its precluded in significant pulmonary hypertension )

Conditions associated with premature PV opening

1. Constrictive pericarditis.

2. Isolated RV restrictive cardiomyopathy (Lofflers etc .Note :Biventricular restriction would prevent premature opening  as PA pressure is raised. )

3. Ebstein anomaly

4.Some  patients with with RSOV .(Acute raise in RVEDP)

5.Post tricsupid valvotomy

Reference