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As the audience, we can oh you can you know you can do it oh perfect that's fine, okay, so uh can you see the slight change yep awesome, uh So this is just a quick recap of the general anatomy of the heart um So, diagram on the left hand side shows the right atrial wall being reflected uh revealing the contents of the right atrium. Can you see my mouse at all could you move that around a little bit yeah. Can you see that you know, Unfortunately, I don't think I can okay well if you just look on the left hand side, you'll see the fossa of ali um labeled um The foramen of ali, closes in most infants during the first six months of life, but sometimes it can persist as an atrial septal defect, which interestingly is found in about 50% of migraine with aura sufferers usually, atrial septal defects are asymptomatic, but they can sometimes lead to complications. Um The left atrium do you know, does anyone know what the pressures are on the left atrium and the right atrium, you can call out. You can't open the chart. Nope, so the left atrium has a pressure of roughly 10 millimeters of mercury mercury. Sorry, whilst the right atrium has a pressure of five, so with a patent foramen ovale, the the blood flow is actually flowing from the left to the right um Now can anyone tell me what is the condition you get when you when you get a reversal off that shunt, I E, from right to left. Any thoughts, can you guys hear me yep, I can hear you ok, fine um It's Eisenmenger's syndrome and it's often you'll see people being cyanosed with it hoops um because it's it's a reversal of the shunt, so you're having um blood, which is deoxygenated, being pumped around the blood, being pumped around the body uh so let's continue on, then so the right atrium uh atrioventricular valve has about three, it has three leaflets, hence the name tricusp, it the pectinate muscles facilitate the stretching of the atria, So if you look at the picture on the right, we can see the papillary muscles. Um These are the muscles that attach the atrioventricular valve leaflets and all of that spongy kind of fibrous connective tissue in the middle is called Trabecula carney. I know and over at the top you can see the pulmonary artery with the aortic arch looming over it okay valves, so we have about four valves in the heart to atrioventricular and two semilunar ones. Um They're also known as a pulmonary valve and uh the aortic valve, so the pulmonary valve is between the right ventricle and the pulmonary artery, and the aortic valve lies between the left ventricle and the aorta. Um The main role is to facilitate the sort of the one, the uni, directional flow of blood throughout the heart, but let's quickly shift the focus to the surface anatomy of the heart for a second um Anyone could could you describe to me where you would place your stethoscope to hear the aortic valve. Um I think I can see who's here, so I don't wanna be calling names, guys, yeah, you're not sure okay so um to find to to hear the the aortic valve you chat oh we do second intercostal space right hand side correct good uh pulmonary pulmonary valve yeah where would we hear that good exactly um and the tricuspid well here on the left fifth intercostal space and what about the mitral valve, where would you hear that one yes correct good uh one of the good, know monix, I like to to recall when. Um whenever I asked I get asked this is all patient's take medication, so aortic preliminary try, cast would mitral uh good okay, let's just go back to this uh okay, so atrioventricular valves, and so the tricuspid valve um we mentioned is found between the right atrium and right ventricle. It has three cusps or leaflets um They are, they are the anterior, the septal and posterior leaflets, whereas the mitral valve lies between the left atrium and the left ventricle and has two cusps, the anterior and posterior the cord, a tendon, er a group of tenderness strands um that are in the heart, which attach the papillary muscles and support the heart valves. The papillary muscles follow ventricular contraction to prevent the vows from opening uh during during ventricular system systole, so we we prevent backflow of blood. We want that uni directional flow um the closure of the of the valves correspond to the first heart sound okay. We'll get onto that in a moment, so the pulmonary valve sits between the right ventricle uh and the pulmonary trunk and has three cusps, the left, the right and the anterior cusps, whilst the aortic valve sits between the left ventricle and the uh and the ascending aorta, which also has three cusps, the left, the right and the posterior uh and it's actually the closure of the semilunar valves that correspond to the second heart sound, s two, so s one is a v valves closing and s two is the semilunar valves closing okay. The heart needs its own blood supply um to be able to pump blood around the body, um and there are two coronary arteries that enable it to um receive that oxygen and glucose um for it to be able to do so. The right coronary artery arises from the the anterior aortic sinus and supplies blood to the right atrium. The right ventricle, the sinoatrial node, and the atrioventricular node and also some portions of the left ventricle. The left coronary artery arises from the left posterior aortic sinus and quickly splits and bifurcates into the left circumflex artery uh and the left anterior descending artery um which ultimately which supplies blood to the left atrium and the left ventricle. The coronary arteries received blood uh during diastole when the coronary vessels are not compressed, um so therefore the heart receives its blood during diastole, ventricular diastole so zooming into the left coronary artery. Then um we have three branches, the left anterior descending, the left circumflex artery, and the left marginal artery. The left anterior descending travels down the anterior uh intraventricular groove to reach the apex of the heart and then um it usually loops down around apex and into the sort of inferior border uh of the heart to form an anastomosis with the posterior interventricular descending branch of the right coronary artery. The circumflex artery travels along the left part of the atrioventricular groove also known as a coronary sulcus and it loops around the left heart border onto the inferior service of the heart, whereas the marginal artery runs along the border off the left heart to supply the left ventricle okay so um just quickly asking you guys, then what um what does the left circumflex artery um supply the left circumflex artery what chamber of the heart okay. Left atrium yes correct good, it loops across the left atrium uh and, and give supply to that good stuff okay. Uh Let's move on the right atrium has two branches um which are the right marginal artery and the posterior intraventricular artery, which supplies blood to the right atrium, the right ventricle um the s. A. N. And the avian and it also forms that anastomosis with the um the the, and the left anterior descending artery that kind of loops around the apex. As we mentioned. So we understand the fundamental importance of coronary arteries um supplying the heart muscle we mentioned with oxygen and um and glucose, but what happens when the coronary arteries get clogged up with low density lipoprotein plaques. This is what we call arteriosclerosis or atherosclerosis, um where in the LDL is the low density lipoproteins deposit into the walls of these coronary arteries, which cause the lumen of the artery to reduce dramatically um thus giving rise to the symptoms of a myocardial infarction, so the gold standard for diagnosing coronary artery disease is a ct coronary angiogram and I've got some pictures uh In the, in the coming slides, a dye is introduced, uh which which allows the coronary arteries to be visualized um and there therefore, we can be able to judge how well perfused they are. Uh If a coronary artery becomes blocked, then we can treat it using a coronary bypass surgery, which creates a new route for the blood flow improving the blood supply of the heart, whereas plaque obstructing coronary arteries can be dealt with using stents or coronary balloon angioplasty, so let's talk about the venous drainage of the heart. Then the venous drainage is mostly through the coronary sinus, which is located at the on the posterior aspect uh of the heart, which which then empties into the right atrium You might have seen in the in the first picture, I showed you guys um There was an opening for the coronary sulcus um the main vessels that contribute to the coronary sinus uh include the the great cardiac vein, the small cardiac vein and the middle cardiac vein, as well as the posterior vein of the left ventricle and the oblique vein of the left atrium okay So this picture just outlines um those different veins and where they kind of uh drain the the chambers of the heart. So these are the pictures of the ct angiogram. Um These are these are all normal vessels uh just to point out to you um which ones are which they've been labeled as well, So you can see the main coronary artery um the the left main coronary artery branching into the left anterior descending um and also looping around to form the circumflex artery. Whilst also giving off these diagonal branch is um the the marginal artery and the septal artery as well uh. Huh here you can see the right coronary artery um it branches into the marginal artery and the posterior um the posterior left ventricular artery uh and the posterior descending artery as well. The pericardium is a membrane that encloses the heart and the major heart vessels. It consists of an outer fibrous layer uh and and in a double serious membrane, the fibrous pericardium is made up of very very thick connective tissue, whilst the serious um pericardium contains serious pericardial fluid that acts to lubricate the two layers uh and in doing so prevents the the act of friction um During cardiac contractions, the pericardium prevents over filling of the heart and also protects the heart from infections um since it's since it's a physical barrier between the heart and the other adjacent organs uh in the mediastinum, which are prone to infections, For example the lungs, the phrenic nerve c three to c five provides sensory innovation to the, to the pericardium and it's a common source of referred pain um for example, referred pain uh in the shoulder due to pericarditis is one of the common symptoms, so um this sign that this referred shoulder pain is otherwise known as kurds sign, I'll type in the chat uh spelled k. E. H. R. So does anyone know what else. Um The Curse curse sign is uh is indicative off okay uh huh mhm not sure oops, let's go back, kerr sign okay, so it is the referred pain um usually felt in the shoulder and it's and it's caused by uh diaphragmatic irritation and it's commonly caused by a ruptured spleen, so splenic rupture um Curse Sign okay okay yes, So This is just a diagram showing you um the pericard and the pericardium uh You got the fibrous pericardium here the serious pericardium um the parietal layer and then you've got this space in the middle filled with the serious fluid. Then again you've got the serious pericardium, which is the visceral layer, which covers the heart um and then um you have the end of the myocardium and then the endocardium mm so the heart is myogenic, meaning it contracts on its own without any stimulus from the nervous system. However, it does receive um the rate control through the nervous system, but we'll touch on that in uh in just a moment, the anatomical features of the conducting system, which you need to know are the essay and the sinoatrial node, the atrioventricular node, uh the left and right branches of uh the bundle of hiss and the perkin GEE fibers mhm, so there are three intern, odle tracks um the anterior, the middle, and the posterior tracks. Uh I've seen in the diagram, which allow the conduction of the s. A. N. To then proceed to depolarize. The avian bachmann's bundle uh is a pictured in the diagram, it's this um track that goes horizontal across the atria. It connects the left atrium to the right atrium and enables almost uh almost simultaneous deep polarization, uh almost simultaneous contraction of the two atria. Once stimulated, the atrioventricular node then sends a signal to the bundle branch is which traveled down. Um The right bundle branch conducts an impulse to the park in the fibers on the right ventricle, whilst the left bundle branch conducts the impulse to the picking the fibers on the left ventricle, so the hispa kinji system is also known as the try fasciculus system um and the three physicals are referred to as the, the right bundle branch, the left anterior fascicle and the left posterior fascicle. You may have heard the term try for sick your block, which quite literally means complete heart block, which is the blockage of all three fascicle. This is clinically different to the right bundle branch block in the left bundle branch block, which have specific features on the e. C. G, um but that will be covered on friday when we talk about the clinical bit, so the heart receives nervous input from the left vagus nerves and and the right vagus nerves um from the sympathetic trunk. So these nodes are known as the the cardiac plexus. The parasympathetic portion of the cardiac plexus only receives contributions from the vagus nerves, which when stimulated, releases a neurotransmitter um to the, to the a, to the a. V. Node, to then decrease the heart rate. The sympathetic portion of the cardiac plexus um only receives innovation from the superior uh the middle and the inferior cervical ganglion, which when stimulated, releases a new neuro transmit to the essay node to then decrease the heart rate. A pacemaker is a small electrical device which is implanted in the chest or the abdomen as well in some cases uh it could be used to treat some arrhythmias that failed to respond to medication. They usually fitted under a local anesthetic uh and weigh about 20 to 50 g. They sit under the collar bone when they're putting uh into the into the chest uh and they're made of metal so they can make going through Airport Security rather difficult. Single chamber pacemakers have one lead um sorry one lead um dual dual chamber pacemakers have to leeds and biventricular pacemakers have three leads, the the whole process the whole procedure to implant a pacemaker may take about 1 to 2 hours uh for most people to get them fitted and uh in fact most people can leave on the on the same day without having to stay overnight okay, so we're talking about the cardiac cycle now um At the P wave, the atria are deep polarized uh and this is where atrial sisterly begins, which forces blood out of the ventricles sorry, out of the a tree it into the ventricles at the QRS complex. The ventricles depolarize, then leading to the ventricular contraction uh pushing the a. V. Valves closed at the T wave. There is ventricular re polarization which corresponds to the um the semilunar valves opening, which allow the blood to be ejected from the ventricles. After the T wave, the semilunar novels will close and the blood flows into the atria uh and this flat line between the T wave uh and the adjacent um P wave correspond to the the chambers filling and um filling with blood and relaxing um passively the e. C. G. Trace can be understood better. If you imagine the journey of the action potential arising at the sinoatrial node, so at first the action potential travels across both atria, they cause simultaneous atrial contraction um The h. E. O. The action potential then arrives at the a. V. N, before splitting up into the two bundle branch is which go down to the apex then come back uh come back up through the perkin gEE fibers, which ultimately stim stimulate a simultaneous ventricular contraction uh which occurs after the qrs so. Um The diagram on the right shows the changes in pressure and volume uh in the left hand side of the heart compared to the e. C. G. Trace. So the first heart sound occurs when the a. V. Valves close, we mentioned and the second heart sound um when the semilunar valves close, uh you can remember the sequences um by c o c like COCO or c o c o so close, open, close open uh and it's important to remember that the semilunar valves are always at a higher pressure, sometimes on an e. C. G, you can see you waves, uh which might be seen on leads to a. B. F. And chess lead to which uh sometimes indicates you hyper, hypokalemia, so you waves hypochelemia and uh conversely we can see tall tented t waves sometimes which indicates hyperkalemia, so how would you treat hyperkalemia with e. C. G. Changes, so tool tented t uh T waves seen on the e. C. G. Uh yeah cachuma gluconate, calcium gluconate, insulin, and dextrose good. Um Sometimes you can also give nebulize salbutamol as well, so uh calcium gluconate stabilizes the cardiac membrane, uh salbutamol, iv, uh incident and dextrose mop up the extracellular potassium and then move it into the cells um So why do we give dextrose, then along with the insulin yes exactly because we do want to induce hypoglycemia by giving insulin good okay, so um got some questions for you guys now. I think we already answered the first one, but uh so what are what artery supplies the left atrium. It's quick fire you guys can type and chat or call out. Uh Circumflex good yes. The circumflex artery originates from the, the left coronary artery, which then loops around uh the left atrium, So it can't be a, as that's another term for the left anterior descending uh It can't be be because that's not a coronary artery and it can't be see either because that is um the right coronary artery supplies the right heart. The right side of the heart okay question too, which vessel drains blood from the left atrium oh hang on that's uh oh yeah okay let's win yeah alexandra is gone for c, which is a bleak vein of the left atrium oh good, so it can't be the, the middle cardiac vein uh because that runs posteriorly and then it's also interventricular, the small cardiac vein is found on the right side of the heart and not the left hand side, so it can't drain the left atrium, the left marginal archery sorry left module vein um drains the left ventricle, not the left atrium, all right question three, which vein is known um as the posterior intraventricular vein alex has gone for be, uh anyone else have anything different be, as well yeah middle cardiac vein um as we've previously mentioned, it runs posterial and also intraventricular it's between allies between the left ventricle and right ventricle. Good okay question for which part of the cardiac cycle is responsible for t, for the T section on an e. C. G. That's uh oh meds gone for e, which is the isovolumetric relaxation, anyone put anyone but anything different from e. Would you guys agree yeah okay, so uh it's not e, uh in fact is d so reduced ventricular ejection. Um This is correct because Yeah excuse me um as ventricular diastole because uh in, in that step of the cardiac uh the cardiac cycle so atrial contraction is the P waves, the eight, the isovolume entry contraction is when the left ventricle contracts, therefore increasing the left ventricular pressure um and the mitral valve closes and the ventricular volume stays the same. So uh you get the rapid ventricular ejection following the qRS complex, so it's reduced ventricular ejection for that one okay and finally last question um what are the cusps of the aortic valve um called where I just got fatigue uh exist, going for a ahmed aortic uh aortic semilunar yeah, yeah okay, so the aortic valve is one of the semilunar valves. Um In terms of the the actual cusps or leaflets, it's not a uh and it's not D either, so the aortic valve leaflets are um left right and posterior, so a, so, the anterior, left, and right, so option A is the one for pulmonary the pulmonary valve option C is for the mitral valve and option D is for the tricuspid valve okay. Um Those are all the questions I had for you guys um Any questions for me, then thank you very much. Sydney for that presentation, I was really good um I'm just going to be sending out the feedback form into the chat um It would be great if everybody could fill that in four um um and uh this there will be a part to um of this talk on friday, so we would love if you guys could come along for that as well. Um yeah um Thank you so much again, Sydney, that was amazing. Um If you guys um have any questions, um uh put them into the chat um and we'll try and answer them and thank you everyone for engaging. Thank you so much for having me. I hope the rest of this series goes well.