Vascular Supply of the Heart (Nursing)

00:01 So let's talk about those coronary arteries.

00:04 The heart is a muscle after all and just like any other muscle, it needs an arterial supply.

00:10 So what we see here is the pulmonary trunk and the aorta.

00:16 Our right atrium, and our left atrium.

00:20 And in order to see these things, we're actually going to have to cut off a little bit of that left atrium to see things fully.

00:27 But coming off of the aorta, on the right side, just in that groove between the right atrium and ventricle is the right coronary artery.

00:38 On the left, it's a bit different.

00:40 We have the left main coronary artery, which is pretty short only about a centimeter or so before it's going to branch.

00:47 And the first branch is going to be the Left Anterior Descending artery or the LAD also known as the anterior interventricular artery because it sits along the anterior surface of the interventricular septum, but most commonly is called the LAD.

01:03 The other branch is going in that groove between atrium and ventricle, mirroring what's happening on the right side, and this is going to be called the circumflex artery.

01:14 Let's swing around to the posterior surface, where we can see the right coronary artery continuing between the groove of the atrium and the ventricle and giving off branches along the way, such as the right marginal branch here at the edge of the picture.

01:30 And then most of the time, it will supply this branch the posterior interventricular branch or the posterior descending artery, also known as PDA.

01:40 Most of the time about 80% or so it will come from the right sided coronary supply, in which case we say a heart is right dominant.

01:48 But it can also come from some of these left branches.

01:52 And if it comes from the left supply, usually a branch of the circumflex, we say the heart is left dominant.

01:59 Rarely, it can have equal contributions from both the right and left supplies, in which case we say a heart is codominant.

02:07 Now, let's talk about the venous drainage of the heart.

02:11 Here we can see the inferior vena cava draining into the right atrium.

02:16 And just to the left of that we see a very large vessel on the surface called a coronary sinus.

02:23 And the coronary sinus is going to be the major venous drainage for all of the veins on the surface of the heart.

02:30 So the coronary arteries because they supply the heart muscle, which is the pump for the rest of the body, are very important clinically, especially if they become diseased.

02:39 In fact, we call that Coronary Artery Disease or CAD.

02:44 And what can happen in coronary artery disease is a portion of the wall the inner portion can get this buildup of atherosclerotic plaque.

02:54 And as it does so, it will compress that space we call the lumen.

02:59 So the space for blood to go through gets narrower and narrower.

03:03 And that can have a lot of consequences.

03:06 But the main problem is the fact that heart muscle is going to need oxygen to pump.

03:11 And if a plaque were to break off and acutely block all of the blood supply, that's how we would end up with something like a myocardial infarction, or MI, or heart attack.

03:24 So what can you do about coronary artery disease is, for example, you can bust that plaque open going into the artery with a closed stent.

03:35 And then with this catheter that has a balloon, you can inflate that balloon and push that plaque out of the way.

03:43 And by doing so you can sort of reconstitute the normal lumen of the artery and restore the flow through that portion of the artery and get that oxygenated blood back to the heart muscle.

03:58 Here we have an interesting form of imaging, called angiography, where a catheter gets right up to the opening of the coronary arteries, and injects a radio opaque dye, which means we can see it on the serial x-rays.

04:12 And by injecting this dye into the coronary arteries, we can actually see how well they flow and supply all the branches that they're supposed to.

04:22 This is very helpful in locating obstructions.

04:25 For example here, where once the dye is injected, we see it go through some branches, but then it abruptly stops at this one.

04:34 And that's concerning, because we know that that means no blood is going beyond that branch to supply that portion of the heart.

04:41 And therefore if it hasn't already, it's at risk of developing a heart attack there.