Coronary Circulation – Heart (Cor)

by Craig Canby, PhD

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    00:01 So that leads us then to an understanding of the coronary circulation.

    00:08 The heart as you might imagine, has an intense metabolic need for nutrients and for oxygen, and there are two arteries that will help supply the heart with arterial blood.

    00:24 At rest, about 225mm per minute of blood is being delivered to the heart through the right coronary artery and through the left coronary artery.

    00:36 Again, coronary means crown and these arteries will form a crown around the heart itself and then issue numerous branches.

    00:48 If we take a look at this view, we can see our right coronary artery traveling then within the coronary sulcus or atrioventricular sulcus.

    00:59 It will wrap around to the posterior diaphragmatic area of the heart and still will travel within the coronary sulcus, and we can see some branches issuing from the right coronary here, in this view, and then along the right margin of the heart we see a marginal artery issuing from the right coronary.

    01:25 The left coronary artery, we see here, it's gonna issue from the aorta, right above the left coronary semilunar cusp, it's traveling posterior to the pulmonary trunk and underneath the left auricle, so the left auricle bridges over the left coronary artery.

    01:46 The left coronary artery at first is a very short segment and then it's gonna issue its two branches.

    01:53 The one that travels in the anterior interventricular sulcus is referred to as the anterior interventricular artery, and then the other one that we see here is going around within the coronary sulcus but it's wrapping around the left side of the heart traveling within the coronary sulcus, and as it wraps around it, this one is called the circumflex artery.

    02:30 When we take a look at the coronary arteries, there is a dominance or dominant pattern that can be determined and if we take a look here, we have our right coronary artery and if we follow our right coronary artery within the coronary sulcus, and see it wrap around the right side of the heart as we do here, we will see that the right coronary artery will dive down into and travel within the posterior interventricular sulcus.

    03:03 When the right coronary artery gives rise to the posterior interventricular artery that travels in this posterior interventricular sulcus, this is called a right dominant pattern.

    03:14 The majority of individuals have a right dominant system.

    03:21 The percentage will vary from one study to another so it might be 70%, 80%, or maybe a little bit higher than that in frequency.

    03:34 And here we're looking at the opposite dominant pattern and if we take a look at what's going on here, we will see our left coronary artery, we see the anterior interventricular artery traveling in the anterior interventricular sulcus which is normal.

    03:51 Another name for our anterior interventricular artery is our left anterior descending artery or the acronym, LAD and LAD is commonly used in the medical profession.

    04:09 The circumflex artery is issuing right at this point and if we follow it around the left margin of the heart, to the diaphragmatic view, posterior view, we see it also traveling in the coronary sulcus, and if we follow it distally, we see it dives down into the posterior interventricular sulcus, thereby continuing as the posterior interventricular artery.

    04:36 And when it's the left, in this case the circumflex that gives rise to the posterior interventricular artery, you'll wanna call this a left dominant pattern.

    04:46 This is the second most frequent pattern that we'll see, however, it is usually somewhere around 8%-10% in frequency.

    04:53 The last pattern that can be seen as a variant is a balance pattern.

    05:03 In a balance pattern what happens is we end up with two posterior interventricular arteries.

    05:11 One coming from the right coronary artery and then if we could move this one over here, more in line here and running parallel to the one coming from the right, we have two more clearly define discernable posterior interventricular arteries that is a balanced pattern, and of the three this one is the least frequent pattern that we'll see.

    05:38 Here we have a superior view of the coronary arteries. Here is the aorta cut in cross section.

    05:49 Here is your right coronary cusp or right cusp and here you can see the ostium leading into the right coronary artery.

    05:59 The right coronary artery in a dominant pattern is gonna supply primarily the right side of the heart, right ventricle, right atrium.

    06:08 Also will supply important structures of the conduction pathway, the SA node and we can see the artery, right here, leading to the SA node and it will also issue posteriorly here most commonly an artery to the atrioventricular node also helps supply the interventricular septum.

    06:31 Here is the left coronary artery, ostium is right here, right above the left coronary cusp and again very short, here you can see it continuing as it enter your interventricular artery or the LAD.

    06:47 This is the one that's most frequently blocked leading to a myocardial infarction and it can lead to death, and so it's also referred to as the widow maker, and then here's your circumflex wrapping around as we see here.

    07:07 Here's your posterior interventricular artery and give you a moment to think about it, which coronary artery is given rise to the posterior interventricular artery and the answer is it's the right one coming around diving down into the posterior interventricular sulcus, so this is a right dominant pattern.

    07:32 The left, in this case is supplying mainly the left ventricle, left atrium, interventricular septum.

    07:41 Like any other organ that's receiving a blood supply, the heart also have structures in place that will help drain the organ of venous blood, so we do have a system of veins to do that.

    08:02 The main veins to keep in mind here as a learner that would be the great cardiac vein, the middle cardiac vein and the anterior cardiac veins.

    08:11 Here in this view, sternocostal anterior view, we can see the first vein and the last bulleted veins.

    08:21 So traveling here, in the anterior interventricular sulcus, out with the anterior interventricular artery or the LAD, is its accompanying vein and blood is flowing upwards here in this system, this is called the great cardiac vein and it's gonna dive into the coronary sulcus wrapped around the left margin of the heart and empty into a structure that we call the coronary sinus, a co-acting system.

    08:48 We can also see here on the right ventricular side, we see in this case three anterior cardiac veins.

    08:59 They're draining in the right ventricle primarily venous blood and they empty directly into the right atrium so they are very small ostia or openings here into the right atrium.

    09:13 The next slide will help us to understand some of the additional veins and also see what we saw on the anterior view, wrapping around here to the posterior view and so what we'll want to focus on here is for a reference is the great cardiac vein coming up and around to empty into the coronary sinus.

    09:40 Coronary sinus will receive most of the venous blood flow being drained from the heart, separate opening, large opening into the right atrium that we saw in an earlier slide when we looked at the internal anatomy of the right atrium.

    09:55 We also have here accompanying the posterior interventricular artery, we have its vein, this is called the middle cardiac vein.

    10:04 It drains blood also into the coronary sinus advance into the right atrium.

    10:12 We also has some smaller veins that will empty into the coronary sinus so the coronary sinus drains most of the heart of venous blood.

    10:23 Anterior cardiac veins are gonna drain primarily the right ventricle and the last system of veins that we have, we cannot see in this view, they run deep within the muscle tissue itself and drain into the cardiac chambers and these are the venae cordis minimae.

    About the Lecture

    The lecture Coronary Circulation – Heart (Cor) by Craig Canby, PhD is from the course Thoracic Viscera.

    Included Quiz Questions

    1. Left and right
    2. Anterior and posterior
    3. Superficial and deep
    4. Medial and lateral
    5. Superior and inferior
    1. 2
    2. 1
    3. 4
    4. 6
    5. 8
    1. Right dominant pattern
    2. Left dominant pattern
    3. Ventricular dominant pattern
    4. Developmental defect
    5. Genetic disorder
    1. 5–10%
    2. 1–2%
    3. 30–40%
    4. 40–50%
    5. 80–90%
    1. Great cardiac vein
    2. Anterior cardiac veins
    3. Middle cardiac vein
    4. Small coronary vein
    5. Left marginal vein

    Author of lecture Coronary Circulation – Heart (Cor)

     Craig Canby, PhD

    Craig Canby, PhD

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    By Hasmik N. on 30. April 2020 for Coronary Circulation – Heart (Cor)

    I will recommend you lectures to all my friends who are doctors. Thank you for your invaluable help

    Excellent lecture
    By Rafael M. on 23. October 2019 for Coronary Circulation – Heart (Cor)

    Excellent lecture. The teacher explains everythig suoer good and it is so easy to follow. I would recommend this lecture to any med student. Thank you Dr.Craig.

    High yield and clear
    By Victoria W. on 04. February 2019 for Coronary Circulation – Heart (Cor)

    Fantastic. High yield with clear information. Very succinct and specific. Clearly laid out and organized.

    By Itayi T. on 10. October 2017 for Coronary Circulation – Heart (Cor)

    I recommend this for any one in medical school who is looking for high yield information.