Thread by @dr_benoy_n_shah

*POSTERIORLY DIRECTED MITRAL REGURGITATION*

How many causes of posterior MR do you know?

Let's take a look in this mini 🧵

But...no cheating...vote first!

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1. Anterior MV prolapse

Probably the first thing that occurs to most people

AMVL prolapse is less common than PMVL prolapse

Here you can see the highly eccentric, posteriorly directed jet of MR

This is the AP3Ch view showing the same abnormality

2. Systolic Anterior Motion (SAM)

SAM of the AMVL tends to (not always) produce posteriorly directed MR; important to remember that SAM is not the only reason a HCM patient may have MR

PLAX here is not mine, it's from an excellent lecture (on YouTube) by Dr @KyleWKlarich

Here you can see the posteriorly directed MR jet on colour Doppler imaging

Here is the still image

3. Ischaemic MR due to posterior leaflet restriction

Inferolateral / inferoposterolateral MI often produces a regional LV abnormality that affects the posteromedial papillary muscle & affects PMVL >> AMVL. The apical PM displacement tethers the PMVL, causing MR

PLAX view here

It may look like there's AMVL prolapse, but if you look closely you'll see the PMVL barely moves

Issue here is PMVL tethering due to inferolateral MI, causing apical displacement of PM pap muscle, thus tethering the leaflet

As a result, we see this highly eccentric, posteriorly directed MR jet

Here's a still frame of that MR jet

4. Atrial functional MR (AF-MR)

Huge atrial enlargement. There are multiple postulated mechanisms for MR in patients with AF - one is posterior leaflet tethering

Again, posteriorly directed MR jet seen here in AP4Ch view

MR still image...

A nice review on AF-MR in JACC Imaging details mechanisms of MR in such patients

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These are the 4 main causes of posterior MR that I'm aware of

If you know others, add to the thread! 😁