Cardiology - Cardiac Output

[@armandohasudungan]

🧠 TEST YOUR KNOWLEDGE FROM THIS LECTURE! ✅ youmakr.ai/test-playground/questionnaire/673d4965859b9c170836f07e

[@armandohasudungan]

Thanks for the comments guys. In regards to ionotropes I spelt that wrong, didn't look at how it's spelt before hand. And also I do also question how hypoxia decreases heart rate. I think it also increases it, but different books tell me different things. One thing is for sure though that when there is a decrease in blood levels and oxygen we tend to increase heart rate as the first compensatory mechanism. How long does this last? Not sure. So maybe hypoxia causes bradycardia in the long run. Don't quote me though. Cheers

[@sotonmedstudent7018]

hi man, great vid. As far as I know, hypoxia doesn't cause bradycardia...until the cardiorespiratory centre in the brain is starved of oxygen and then starts shutting down. By then though...the person is pretty much dead... or will need serious resuscitation. The body is really quite good at maintaining cardiac function under "normal" conditions, even in conditions of hypoxaemia. When the paO2 drops to around 8 kPa, (normally >10.6 kPa) the carotid chemoreceptors detect this fall and start ramping up cardiorespiratory rates (breathing and HR). Even if someone is chronically hypoxic, like someone with COPD, they can maintain a good enough cardiac output to not really notice until they exercise.

[@molanm4390]

well let's see if that benefits, I studied that mild hypoxia causes tachycardia due to stimulation of CAC and CIC, but severe hypoxia causes bradycardia due to damage of medullary center and nodal tissues of the heart (end in death)

[@diplomat2623]

LOVE your videos!!!!!

[@emmelineduong]

Hello! When are you are hyperventilating wouldn't you have a higher loss of CO2, so then you would be hypocapnia?

[@farahkhan1964]

sir hypercalcemia increases heart rate

[@carolinagondra1338]

Excellent video! I passed my final histology exam thanks to one of your drawings of the skin layers! And now I am taking physiology. Great video. Helped me organize what I learnt in class.

[@keylidxaffar9894]

@Success Nduka Oduwegwu and i also passed my philosophy through this video. lol

[@aurara96]

I think I finally am starting to understand preload and afterload. You have an amazing ability to explain difficult material in a manner that is understandable! I look forward to future videos :D

[@loveliveallthetime]

FINALLY!! The video I've been wanting you to post!! MUCHAS GRACIAS!!!

[@adnanbashi9793]

You my friend are a Legend

[@Datboigioo]

*is

[@armyyyyyyyyyyyy]

Fakhri Hakim are**

[@urbanproductions5584]

@@Datboigioo are

[@quangvu1950]

You're a true savior!!! Not all heroes wear capes.

[@OneSkiWonder]

Watching this video was required as part of my AEMT refresher. I think that says that you've done a damn good job making the video. :)

[@brunaprilipali8628]

Your videos are the best! I have been learning a lot from your explanations since 2013! thank you so much! you really make the difference here!!!!

[@mrdb3po]

easily the most clear presentation on cardiac output. Thanks Armando!!

[@elinequirijnen922]

You are helping me during these crazy corona times. Thank you very much!!

[@hanachase]

daaaaang. this is amazing. awesome art skills and an excellent explanation. thank you!

[@AisazzZ]

Great Video! But can someone plz explain how does hypocalcemia causes tachycardia?

[@freddymendez4698]

Great Job, nice and clear. I'm glad you mentioned the positive and negative chronotropic & ionotropic determinants in HR and Contractility, I had overlooked them and thanks to you I'm good on them! Again keep it up. God Bless!

[@Intentionallycourageous]

Thank you Armando Hasudungan. Your videos really help.

[@DivineSweetheart]

I love your videos. Very helpful indeed. Thank you so much!

[@RueAdunola]

This was definitely a GREAT video

[@fahiroumaima923]

can u make a tutorialof how to draw a heart like this ?

[@shristidas7977]

Lol...i feel you bro

[@22-mohanyadav41]

😂😂😂

[@17cardigan21]

You make some incredible videos! Very helpful study tools. The only thing that I could suggest is showing one final screen shot of everything all at once. That way you could test yourself using that image. Thanks again for these amazingly helpful videos. I hope to see you illustrating anatomy text books one day.

[@ubiquitousfan4721]

Agree.

[@2012javad]

Phenomenal job man. Well detailed

[@emmasarovich7092]

Hi Armando Thanks so much for your videos they are helping me greatly through my health degree. You explain things so clearly and your drawings are fantastic. Awesome.

[@lumaluma2830]

Thank you very much,you saved me,I have exam and I was not understanding anything

[@emmanuelohisadominic8097]

Thanks so much for the great work done. I always like this kind of learning, once again, thank you.

[@AmandaVeniVidiVici]

You say at 5:15 that preaload is the volume entering the heart, but preload is the total volume of all the blood in the heart at the end of diastole (including direct flow, retained flow, delayed ejection flow and residual volume).

[@AmandaVeniVidiVici]

At ~6:00 you also say that the amount of blood entering the heart is about equal to the amount leaving the heart and that is true. But directly after you say that that "end diastolic volume ~ stroke volume", and that is not correct. The end diastolic volume is ~120ml for a normal person. At the end of each heart stroke there is about 50 ml left in the heart (the residual volume). The normal stroke volume is 70ml (120-50=70). This can be seen in a pressure-volume-loop.

[@anasabusaid2076]

This what we called innovation thank you so much for your help

[@NosaMandili]

Great video ! Are we able to download your notes that u draw?? it's gonna be so helpfull.

[@clairefalcon8432]

amazing video! It is so clear and really helped simplify things ! Thank you !

[@mgt6984]

Wow, thank you very much for this lectures. Very educational indeed,

[@Edutainment369]

Really nice one Sir... knowledgeable...am 4m India

[@makakaoshi]

Good video. Greetings from Chile.

[@shazak9095]

in the video you stated that hypocalcemia is a + ionotropic effect, and then at the end you said that hypErcalcemia is a + ionotropic effect, which one is it and why?

[@pennstizzy]

Thank you, very helpful. Will apply this knowledge to clinical application.

[@avnibansal2248]

Love your videos

[@throughthescope7652]

First comment,lol. Thank you for these videos, they really make things easier for me.

[@gulleranaahmad5617]

at 3:22 How does decreased calcium increase heart rate? Also, you said in hypercalcemia, there is an decrease in heart rate but you wrote increase in heart rate. Calcium is the main contributor towards rapid increase in the membrane potential therefore, calcium and the membrane potential (or HR) have a direct relationship. Clarification please.

[@jawharahh.5222]

+Gullerana Ahmad I'm also wondering how is that could be true? he also mentioned that in contractility Hypercalcemia increases it (contractility)!!!! so how the hypocalcemia can increase the heart rate I wish someone explains that

[@theventraaramakrishnan7631]

i looked up in google. im not sure whether it"s correct. hypocalcemia causes prolonged qt which can cause tachyarrhythmia.

[@arasonyth3243]

A healthy heart will have enough calcium to effect the action potential and keep the heart beating. The calcium he is speaking of is that which contributes to Inotropy, which you can understand as a separate idea. In very simple terms, the contractility of the heart will be increased by an intracellular increase in calcium. It pushes the heart into further contraction than it's base rate. As a result, stroke volume is increased and cardiac output is increased. Here is the important part. The human body maintains a particular heartbeat within a range, usually something around 50-60 beats per minute in an average person. Why does it keep this particular range? Well, it is determined by many factors, but the concept is it is enough to supply the body with what it needs. It keeps a pace that maintains the body's requirements while also not exhausting itself, a pace. This maintains a certain blood pressure, around 120/80 for an average person. If you increase the contractility with increased intracellular calcium via an ionotropic drug, like digoxin, or a drug with ionotropic effects, like digitalis, then you are increasing the pressure and the resources that are going out to the body. This isn't metabolically necessary, which is why the body will revert back to it's set point after the ionotropic drug wears off. But while it is exhibiting this increased contractility, in order to compensate for the increased and unnecessary cardiac out put and pressure, the heart will SLOW DOWN. Stroke volume is increased, so heart rate will decrease to maintain the set point for cardiac output as determined by metabolic need (read: baro/chemoreception). This leads to bradycardic effects. In cases of reduced calcium (once again keeping in mind there is enough for the action potentials to continue), the stroke volume will be reduced as the cardiac muscle is not contracting as much. In order to compensate to meet the set point, the heart rate will increase. Tachycardia in hypocalcemia, bradycardia in hypercalcemia. It's important to realize things do not just have "positive" and "negative" effects on the heart, there are multiple variables at play to maintain a system. A year later, hope it helps someone.

[@yuuiji]

Thanks for good explanation. I actually just initially thought that low calcium would lead to less sustain of depolarization, increased refraction and therefore increase heart rate. But I think I like your explanation better XD

[@azharsheikh2912]

So basically you're saying that it is a basic physiological compensatory response. Increased intracellular calcium (hypercalcemia) will cause hearts natural pace making ability to try to reduce the HR and SV thus decreasing cardiac output since the body, under non-strenous activity and decreased oxygen demand, dpes not require that much cardiac output thus slowing down the heart rate hence saying that hypercalcemia causes bradycardia Opposite would happen if the heart rate is reduced (bradycardic), stroke volume reduced thus cardiac output is reduced this means the heart must compensate for this by increasing intracellular calcium levels (hypercalcemia). Is this what you're saying?

[@istapraqzun4303]

You are the best... I only kam for your videos

[@yomarie09]

Hi, can you make a video about the hemodynamics of the cardiovascular system; Resistance, blood pressure, velocity of flow? TY

[@zollingerellison1998]

you are great ,man👏

[@adarshsrinvas98]

Your videos are really useful...Great job!! ..Please make a video on cardiac regulation .....

[@jaseenajazpkl3544]

thanks a lot sir...all ur vedeos are very usefull

[@esito069]

Very well made, thanks for that.

[@madisoneckhart7999]

Fantastic video.

[@Christina-ds7qk]

you are the best! thank you for making this!

[@sokarburhan324]

thanks for you amazing way to teach us☺️ I get benefit from your video more than from my doctors! could you plz upload your writing ?!

[@WaiKeat66498]

Very good video! Thank for upload

[@aswinanandh8964]

Such a great video to understand Thank you

[@johnfrietzhinahon9750]

i disagree with regards to the equivalence between preload and end diastolic volume. there is what we call ejection fraction, which is a percentage of volume being ejected from the ventricles. this means not all the end diastolic volume is being ejected per pump. it's only a percentage. great visual presentation though. i like it

[@Shahnawaz15121]

thank you so much Sir your videos help me a lot

[@mpfunder02]

I love these videos

[@gaara.wifeyy]

I enjoyed this very much! thanks!

[@hannansabah]

nice drawing and explanation well done

[@syedtameemulhassan5772]

Decrease Cacium is + chronotropic? More the calcium you give, more will be contraction. So it is basically an inotrope, a positive isotrope. Chronotrope are for rate. Inotropes are for contractility. Dromotropic are for conduction velocity. Please correct me if I am wrong.

[@hayderjawad7007]

+Syed Tameem Ul Hassan i think that increased ca+2 will decrease the time needed for AP (action potential) .in this case, we shall have more action potentials over time (i.e each minute) and so more number of beats per minute which actually means increased heart rate (+ chronotropic effect in pharmacological term)

[@edwardherrera846]

Calcium influx is a part of the cardiac pacemaker cell's action potential. So increased calcium levels will increase the conduction through the SA node and increase HR (chronotropy) but will also increase contractility. Just like giving someone a calcium channel blocker will decrease their HR along with decrease contractility.

[@sebetsomatshitsa6614]

My understanding is that, the plateau phase of action potential is due to the slow influx of ca2+ hence implication is that, there will be increased time for action potential conduction as the muscle contraction will be sustained with more ca2+.

[@93revenge1]

Man your are the best!

[@Ice-jl4pq]

This is really great! Thank you so much!!

[@magdalenansa8096]

Thank you this video was so helpful

[@silviaboneva7283]

Thank you 😊

[@ishrathfatimi1049]

excellent videos

[@JuliaLivesCrazy]

just wanted to say thank you!!

[@muneebaec2841]

Thank u so much . Its so helpfull

[@ayaosama8983]

Thank U very much ... it's simple and brief

[@Syzyro]

Excellent video, very helpful. I have one question though. Help me understand why is hypocalcemia a positive and not a negative chronotropic factor?

[@esraamowafy8009]

Thank you

[@jamesstark5008]

Good, concise vid. Thannks

[@marcialbonifacio3285]

thank you very much. this was very helpful

[@terencelouiesua4398]

Thank you for the videos, hope you can also attached the reference you used for further study.

[@Adityadraw]

lovely videos from you

[@Medi-Nor]

Excellent ☝🏼👌🏼👏🏽✍🏼

[@abidindicle8882]

Tû her hebî mamostê ye heja

[@shanbazaz]

Did you ever upload the video about the cardiac cycle ? I'm talking about the graph you mention at the very end. Can't seem to find the video about the subject.

[@yarahazemgsf8902]

Hi Armando , I have a question related to hyper\hypocalcemia , I don't understand how Ca++ affects the HR , I understand how it affects the contractility , but I don't understand how it affects rythmisity of the heart , would you please explain it to me ?? thanks for your great videos

[@ahmedraouf9213]

I agree with you , i have the same problem , need help for the explanation , even though , pacemaker action potential needs Ca++ for depolarization phase , and in this video it is mentioned that hypocalcemia causes tachychardia ?????

[@kr210785]

Yes, i am wondering the same thing. This is the only thing i'm confused about...

[@yarahazemgsf8902]

still confused till now .. didn't find answer

[@anitakumar2634]

Hi! Awesome video! Are we able to download a copy of your notes that you draw up? Theyre amazing!

[@lorenapinedo2316]

Great video, where is the second part?

[@mehrrizvi2625]

This really helped, thanks a ton.

[@paolaandreaduranmartinez1741]

finally. I understand the cardic output wow! :)

[@ahmedraouf9213]

thnx a lot for this nice video , but what about the continue of this video ?

[@mustafaalais1243]

hey man great work .... are you going to make a video about ECG soon ??

[@armandohasudungan]

mustafa abboud One day! one day..

[@bansoorshaik7543]

Excellent sir

[@skyman2906]

Thanks ,Best lecture!

[@stephanieisidro711]

you are awesome!

[@hussam023]

Gr8 video. Helped alot :)

[@pediatrician6572]

thank you.

[@samruddhisonkar943]

thank you very much......

[@selimeaksit1749]

Best best best videos everrt

[@time_traveler35]

Does hypercalcemia raise or descend the heart rate??

[@A211992]

Hello. Can you upload the picture you have drawed?

[@marebearzzz027]

SO GOOD!

[@kenziebeveridge]

awesome video... super helpful and beautiful drawings. i have to ask though... what kind of pens are you using? they’re incredible

[@armandohasudungan]

Hey I use artline markers in this video. But recommend Fabercastel finepens

[@namjoonismyhusband1530]

Can someone tell me where can I find the cardic cycle graph video? it's not there?

[@mohammadragheb4962]

Me too 😢

[@ubiquitousfan4721]

What cardiac cycle graph? You mean, what you see in the ECG?

[@hsmnadhrahzulkifli7859]

did u find the video?

[@11ayesharinad27]

U can go through Guyton ✌️

[@elanko2804]

continuation of this video is missing.where can i watch it?

[@abdelraheemahmedtagian5901]

Very good

[@kriselavojniku7891]

Excellent

[@aptxxx]

it's calcium? it should be potassium right?- with high K+, heart stop beating

[@saniyabaghel157]

Exactly what I am thinking abt... increase in ca2+ level increases heart beat I guess...and potassium decreases ..I guess

[@Tasha19ist]

brilliant :D easy to follow too thankss

[@chiranthiekarunaratna3205]

I get why there would be -ve ionotrophy with hypocalcemia (and vice versa) but why +chronotrophy with hypocalcemia?

[@juliancristy6128]

Thanks!

[@roger328053]

Thank you very much.. One question, why positive chronotropic raise hypercapnia? farewell

[@carolinetan194]

Thanks very much :)

[@Jessicad654]

You're smart and you can draw. Just curious, how many of those markers do you go through? Haha

[@shanonchris6083]

Morgan Aldredge he has predrawn drawings ...with pencil

[@asdasd446446]

Really thank you for doing all of this . but is the ejection fraction is the stroke volume ? thank you .

[@PhoenixRising-21]

Would you please continue to post your pictorial diagrams on google drive. Thank you for your dedication and assistance with knowledge acquisition to all of us thriving to understand the complexities of science.