Prof Darrel Francis ☺ Mk CardioFellows Great Again Profile picture
Cardiologist, Scientist. I separate taking my work seriously (I do) vs myself seriously (I don't) Ideas my own (best ones stolen from my amazing PhD students)
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7 Nov
This is awesome on so many levels.

Can you count the levels?
Hat tip to @DrAhranArnold for grabbing this before the telegraph deleted it in shame.

1. What is real world data? What are the alternative worlds where data come from? Telegraphia?
2. Does one week being lower than the previous prove it is the peak?
Read 5 tweets
7 Nov
Yesterday, I tweeted that specialty societies rarely say "don't do our technique, in situation X".

Today @CardiacJoshi found a counterexample:
In between my tweet and Joshi's, I was speaking to David Oxborough, R&D lead of Brit Soc Echo, about a UK-wide Echo AI research programme we are planning.

(I obviously didn't mention my little faux-pas of being rude about societies. I hope he is not on Twitter.)
Anyway my original tweet was along the lines of:

Societies always say their technique is good for X, "always", "sometimes" or "rarely", and that is boring.

It's only when they say "DO NOT DO IT FOR CONDITION X AS IT IS RUBBISH", that it is really exciting.
Read 7 tweets
3 Nov
This is why I could never stand for election for the society of X or y technique. And even if I was crazy enough to do so, I would certainly never be elected !

You must publically advocate that the technique is wonderful and amazing.

If I was president of the E wave society...
I would have to consistently argue,

"Measuring the E wave is the fundamental axiom of cardiology."

"E waves contain more information than the entire rest of the echo!"
Meanwhile my brother, Barrel Francis, with whom I am on excellent terms in daily life, would have to publically pronounce the opposite.

"Pish and tish on the E wave! A wave rules!”

"A wave first, alphabetically and always."

"A wave so important that it's loss in AF is fatal"
Read 5 tweets
2 Nov
I have combined Guy gadboits and Voids answers to come up with a pictorial solution.
You need the two breaks to be on opposite sides of the stick (since if they are on the same side, one piece will be greater than 1/2, so the other pieces can't match its length).
Probability 1/2
But given that they are on opposite sides, you ALSO need them to be not so far apart that the central segment is >1/2.
I.e., wherever the left break is in the left half, the right break needs to be to the left of within the right half.

By symmetry, this has probability 1/2.
Read 8 tweets
23 Oct
This Sam Loyd question is generating lots of very nice equation-based answers, but let me try a method, derived from Zugzwang et al, to see if I can do it without so much algebra, just by thinking.
Suppose we CHANGE the question to this:

"The hour hand and minute hand are SUPERIMPOSED on each other. How long till this superimposition next happens?"

Here is my approach. Suppose it is now just-after-two o'clock. When will this next happen?
First answerer is correct.

And this will continue on in a similar pattern.

When you get to "just-after-11 o'clock", what actually is that time, after 11 o'clock, that the hour and minute hands superimpose?
Read 7 tweets
29 Sep
Finding the stats tweetorials hard?

Some easier questions.
Examine the quote tweets on this tweet, and answer the questions that follow.

Here is the claim:
What would you do if you see this tweet?
Read 18 tweets
14 Sep
When your patient adverse symptoms on statins, what should you do?
Here are 4 choices
When will they stop taking the statin?
Read 56 tweets
11 Sep
Everyone who dies of Covid today, got it from
Suppose on average it takes 10 days from a person being infected, to that person passing it on to the next person in the chain.

Let's say we are about 500 days into the pandemic.

If I get it today, how many people long is that chain that led to me?
The mortality of Covid infection, without vaccination, is around half a percent.

Suppose the Covid I get today, kills me.

How many people in the chain of ~50 that let do me, on average, would you expect to have died from it?
Read 11 tweets
10 Sep
This is very funny.

Does anyone know if this person is actually a doctor?

Or has somehow just managed to get through medical school without noticing how science works?

If someone makes an allegation, one can

(a) ignore it,
(b) conduct experiments to test for it.
If you ever feel a bit dim or slow witted, just click the link below which lists hundreds of commentaries on the above tweet.

Click on it, scroll to a random point, and realise that actually, you are very fortunate to have received an education.


So, should we get special, "other", disposable, people to take it, before we do?

Are people who enter clinical trials "fools"?

We just sponge off their altruism, shall we?
Read 8 tweets
6 Jul

I was just about to say, "Looks fine to me” ...
... when I suddenly noticed this.
And once you see that, the whole thing unravels.
Read 4 tweets
23 Jun
I see Prof Chloroquine has decided to sue Elisabeth Bik for annoying him by pointing out the dubious features in his claims.
The MOMENT a scientist takes legal action instead of answering the scientific questions, you KNOW the answer.

They may as well come out and say it!
So if anyone is enjoying using INSPIRION to learn simple medical stats ...…
Read 6 tweets
22 Jun
Ahhhh, interesting that Josh brings this up!

h/t to Sanjay Kaul @kaulcsmc and DJ Cohen @djc795
for highlighting how difficult it is for people to redirect their thinking
What dose of metoprolol do you consider standard?
Here is the UK's British National Formulary (equivalent in role, I believe, to the US Physician's Desk Reference) regarding standard short-acting metoprolol.

Read 44 tweets
30 May
A question that I thought was simple, has had enormous pushback from respondents. 50:50 are ardently espousing an answer I consider to be obviously wrong.

Suppose there is a shop which only lets you in if you bring exactly ONE child.
Each person going shopping has two children, and chooses one child to go with them, but ALWAYS takes a boy if they have a boy.

For a randomly chosen customer in the shop, if their accompanying child is a boy, what is the probability that the child at home is a girl?
Let's give it a few days to see how people vote.

Please don't give the answer away, as it will spoil the experience.
Read 21 tweets
21 May
I'm so excited!

PCI proven to save lives!

And we in ORBITA have played our part!
A picture tells a thousand words. And if you use a thousand colours, it tells a million words.
Here we are! The bestest trial in all the world!

Today I am happy to say I am something to do with it!!! No longer am I saying I had nothing to do with it and it was just something @rallamee was doing without my knowledge.
Read 12 tweets
17 Apr
I do admit I pour vitriol on fellows who say NYHA is 2 to 3.


"Whats the point of going to medical school and then training in cardiology? Could have just gone to the pub."
NYHA has 4 possible values.

The cleaner could tell the people in NYHA 1: they are basically feeling normal.

The cleaner could also tell people in NYHA 4. They are slumped in a chair or bed, breathless at rest.

Everyone else is in 2 or 3.
Therefore the entire purpose of the 10 years of medical school, cardiology training, PhD and whatnot, is to be more skilled than the cleaner, i.e. to be able to distinguish NYHA 2 from 3.
Read 23 tweets
15 Apr
Yes but this is not because they are evil.

It is because they feel that they are responsible for being advocates for their craft. That is why we congratulate people who broaden the indications for an intervention, and shun those who narrow it.
The Echo CRT trialists did an excellent job discovering that CRT given to people with only mechanical dyssynchrony, killed you progressively over time. In the same way that CRT for LBBB saved your life progressively over time.
In other words they showed that it was not a procedural complication problem (that happens soon after the implant) but a progressive result of the pacing itself.

They rarely get credit for this exquisite insight.
Read 7 tweets
11 Apr
I like this analysis.

However take no notice of this. I am an interventionist and it shows a reduction in some sort of events, when interventionists do our thing, so I am bound to like it.
What I do when I read research is ask myself who organised it and why.

It's not their fault, we are all creatures of habit and are biased.
The meta analysis was by Avi, who is understandably desperate for a resounding victory for PCI.

I am too, but just less energetic in my searching, with every passing disappointment.
Read 9 tweets
4 Apr
When this happens ...
What be your response?
Happily the plumber fixes it. He explains that this is a problem with blockage in the pipes that he had to clear.

You tell your neighbour about your lucky escape with your life.
Read 36 tweets
23 Dec 20
Tony Blair is (for once) right that the most efficient use of the limited vaccine supplies would be to give everyone (who wants it) one dose, and once that is all done, and more vaccine is available, go back for 2nd doses.
HOWEVER, much as I love to kick the government, I can see fully why they are NOT doing this.

If I was the head of my village in Outer Francisia, and I had only n vaccine doses for my n people, I would give them all 1 each. (If I had less, I would give to the most at-risk)
... based on this startling graph
Read 49 tweets
15 Dec 20
Very interesting question. People do still seem to misunderstand that creatures need to have an aim in mind when they do things.

The beauty of life was that it needs no more explanation than a ball rolling down a hill.
You could say that the ball "wants" to go lower if possible. But ultimately it is being dragged that way by gravity.

We can use the term "want" loosely, when describing inanimate objects:

"The heat in this oven wants to spread out evenly"

But we know it is only shorthand
The mistake that leads people to think that viruses and other creatures particularly want to spread, is that Darwin's principle is often quoted as "Survival of the fittest", and we often misunderstand that as "Survival of the fittest creature".
Read 22 tweets