Hi, thanks for the question, which highlights an important point. The convention to demonstrate flow towards the probe as red, and away from the probe as blue, only works for blood which is flowing at relatively low velocities. If we look at the clips in which the AR is demonstrated, the scale is set from +61.6cm/s to -61.6cm/s. When set like this, the software can correctly identify the direction of blood flow, as long as the apparent blood flow velocity is under 61.6cm/s. Once the apparent blood flow velocity exceeds this, the software cannot determine the direction that the blood is travelling, and incorrectly asigns the flow the wrong colour (we term this 'alaising'). We can't just turn up the scale, because Pulsed Wave (PW) Doppler, of which Colour Doppler is one form, has an inherent maximum speed limit. Blood velocity largely depends upon the pressure gradient between where the blood is coming from and where it is going to. Aortic regurgitation is leaving the aorta and going to the LV, in diastole. Let's imagine a situation whereby we have an aortic iastolic pressure of 72mmHg and an LV diastolic pressure of 8mmHg. This gradient, 64mmHg, would be expected to generate a blood velocity of ~400cm/s, far in excess of our scale. Indeed, as a general rule of thumb, most abnormal flow in the heart is high velocity, and so will almost always lead to alaising. 'Normal' flow in the heart tends to be much lower velocity, because a high gradient represents resistance to flow, and the normal heart is designed not to introduce unnecessary resistance. Even these 'normal' lower velocities frequently exceed the Colour Doppler scale, leading to alaising. I have a video which explains just why this happens, which you can see here: kzbin.info/www/bejne/n4W6nalod8l-pposi=4qgysUtcGGhP5_pi

@@richardfisher9916 I see, it is a limitation that could be misleading, thank you very much for the explanations sir

Hi. This is a good idea, to have a second camera recording the console. I will definately consider it for future videos. Thanks.

Glad you find these helpful. Each video takes a very long time to produce, and I need to fit in in around all my other commitments. Having said that I would love to be able to get back to making these in 2024.

Hi P, thanks for the questions. Firstly, in a dynamic state, where the blood is always flowing, it helps to think that it is differences in pressure which cause the flow and hence the change in volume. So imagine that volume is dependent upon pressure. When intra-thoracic pressure drops during spontaneous inspiration, RA pressure also drops. It is the drop in pressure which entices more blood in to the RA. You can imagine that the negative pressure aorund the RA is pullig the walls of the RA apart, creating more space for additional volume. With respect to the question about is increased RAP good or bad, I think it is maybe helpful to distance ourselves from the terms of good and bad as absolute terms. We do know that in spontaneously ventilating patients, who have normal cardiac structure/function and are not acutely unwell, RAP is usually in the low single figures. This is where we expect RAP to be in health. In general a capable heart will try to keep venous return moving on, and therefore maintain a low RAP. There are of course exceptions. Some patients may develop a stiff right ventricle with restrictive physiology (a cohort in which I have seen this is adults with repaired tetralogy of Fallot). They have elevated RV end-diastolic pressure and therefore are reliant on an elevated RAP in order to fill the RV. In these patients a low RAP would be inappropriate. As is usually the case, assessments must be made in context, and consider all of the observations together, combined with what you know about this individual patient and their current condition (i.e. what - if any - acute pathology, will be effecting their physiology).

Thanks Amir. I enjoy making these so I'm glad they are helping you. They take a long time to produce however, and I never has as much time as I would like (who does?). I would love to get one more done this year if possible (or maybe creeping in to the new year).

Most welcome Ayman.

ありがとう。

Thank you Ayman, I'm glad you find it helpful. I work in critical care, but the lectures are aimed at anyone studying echocardiography, so great to get feedback from someone training in cardiology. Good luck in your studies.

Dear Khaled, this is a great comment to wake up to. Glad these videos helped. May I ask which examination you were sitting?

Hi Ganga, you are absolutely correct that the audio for this video is not great. I bought a new microphone after this and I hope the audio of videos made after this one is much better and easier to undertand. I have recorded another video going through the Level 1 minimum dataset with better audio, which you can see here: kzbin.info/www/bejne/qqe9dZKBdt59ZqM

Hi Michael, thanks for the encouragement. I had loads of plans for further lectures, and I had intended to cover the level 1 syllabus by the end of 2020. Unfortunately COVID... The pandemic is still pretty full on here in London and clinical work in ICU takes up most of my time. However I have been working on the valves lecture which is half way complete and will be up here at some point. Would be great to get the remainder of the first series of lectures online this year (2021), but global health emergencies may have other ideas.

Does BSE does any course ? Or is FUSIC / FAMUS the only one available?

@@ankitasingh-pl4nx Hi Ankita, the Foundations of Echocardiography course is specifically designed for people studying Level 1 echo. We had plans to run 7 courses at 6 centres around the UK in 2020, but then COVID forced us to cancel all of our face-to-face courses. I will restart them soon I hope, I think it depends what the next wave of COVID cases looks like in the next few months. I advertise FoE courses on twitter: @EchoFoundations

@@richardfisher9916 Thanks alot.

You're welcome Peter.

Thank you Iliass.

You're welcome. Personally I struggle with dense text, and imaging, especially moving imaging lends itself so much more naturally to being taught with moving pictures rather than stills on a printed page.