Cardiac anatomy is one of the important basic knowledge for cardiovascular physicians, and mastering the morphological anatomy of the heart is beneficial for understanding heart valve diseases, cardiomyopathies, precordial diseases, and other diseases. The localization of infarction, ventricular prematureness, ventricular tachycardia, the general localization of preexcitation bypass, and the folding mechanism of atrial flutter and atrial fibrillation in our electrocardiogram are all inseparable from the knowledge of cardiac anatomy.
In recent decades, with the development of 2D ultrasound, cardiac CTA, cardiac magnetic resonance, PCI, radiofrequency ablation, and intracavitary electrophysiology, the cardiovascular anatomy has become more demanding for cardiologists, and some parts of the anatomy that were not important in the past have been given new meanings;
Previous anatomical knowledge can no longer meet the requirements of current cardiovascular progress, so our knowledge of cardiac anatomy can no longer stay at the level of previous systematic anatomy, but needs to analyze cardiac anatomy at four levels: gross cardiac anatomy, cardiac angiographic anatomy, cardiac tomographic anatomy, and cardiac ultrasound anatomy at sea, on land, and in air.
The Clove Cardiovascular Time’s Insects will use these four chapters to introduce you to the most closely related knowledge points of cardiac anatomy and clinical applications, in order to open a door to understanding cardiac anatomy and clinical, the arduous and fun road of cardiovascular exploration depends on your own expedition, I hope these scattered signposts can let you take less detours on the road of cardiovascular exploration.
Now we will start the “Heart Anatomy Notes: Right Atrium and Right Ventricle Chapter”.
The anatomical terms have been labeled, so I believe we are all familiar with them and will not expand on them.
As usual, this is not the highlight, the following is what Bug wants to tell you about the correct spatial view of the heart.
The correct spatial view of the heart is like the correct view of life, walking in the jungle, the wrong view of life, he will easily take the wrong path, similarly, in the heart anatomy without the correct spatial view of the heart, will be in the heart tomographic anatomy, ultrasound anatomy, angiography anatomy on many detours. This is why at the beginning of the diagram section of Bug, we will not hesitate to explain a correct spatial view of the heart.
In the end, the spatial view of the heart is very simple, in a word: to understand the visual imaging of the heart from the correct visual perspective; LAO 30° will not appear as RAO 45° angiography, heart tomography plane will not appear as four chambers in front of the morphology, the anterior-posterior position of the heart will not appear as left anterior oblique imaging. It is simple to say, but in fact, people often make mistakes in thinking in a fixed way.
Xiao Ming’s father has 3 sons, the oldest is called Da Mao, the second is called Er Mao, the third is called what?
Sanmao! Wrong, his name is Xiao Ming! That’s a stereotype. Similarly, left and right are given the concept of symmetry in our subconscious mind: left hand, right hand, left foot, right foot, left eye, right eye, symmetry, right, while the middle and middle are given the concept of center – nasal septum, central sulcus, median line.
The heart is divided into left atrium, right atrium, left ventricle, right ventricle, among which there are interatrial septum, septum —– This subconsciously gives us a hint of symmetry, but from the frontal visual perspective of the heart’s left atrium, right atrium, left ventricle, right ventricle, the performance is quite ineffective, not only asymmetrical in form, even the location is not symmetrical. There is no picture, so it is good to get a picture.
Choose a 30-degree angle of the heart and make a clean cut (remember to make a clean cut without delay), and the visual effect will be as above.
This is the most beautiful view of the heart – a four-chamber view of the heart. The four-chamber view will be mentioned in detail in the ultrasound view of the heart to be released later. If we look at the heart from the front, the septum is almost in front of us obscuring the entire left ventricle, leaving only a little of the apical part visible.
In our frontal view, we see the entire right ventricle, while the left atrium is completely behind the heart, and further back is the esophagus, trachea, and spine. Therefore, it seems more appropriate to call the right ventricle the anterior ventricle and the left atrium the posterior ventricle, which are symmetrical in position, while the right atrium and left ventricle barely qualify, as they are symmetrical on the left and right.
Here are two simple examples from Bug to show you what the correct view of the heart can do.
With a correct view of the heart we would not be looking for the left atrium and the right ventricle on the left side of the CT film, as shown in the picture.
With the right view of the heart we know that if a person has a funnel chest, it is likely to compress the right ventricular outflow tract and not the left ventricle, as shown here.
To help pro’s understand this again, Bug has made the right ventricular free surface transparent we should see the heart and septum in front of us with this effect, and a similar view of the spatial concept of the heart will be implemented in the subsequent chapters.
Okay, the appetizer is finished, and we will now formally enter the gross anatomy of the heart.
Let’s start by cutting the right ear open and turning it outward to see if the right ear is more like an ear? These structures inside the ear are called comb muscles, why are they called comb muscles?
The heart ear is located above the atrium, blood flow is already slow, when atrial fibrillation blood flow is even slower, plus the left and right ear these longitudinal and horizontal comb-like muscle structure, so it is easy to form a thrombus here, so atrial fibrillation more than 48 hours to anticoagulation therapy for 3 weeks to resume rhythm. On the one hand, it is necessary to prevent the formation of new thrombus, and on the other hand, it is necessary to mechanize the already formed thrombus. In addition, even if atrial fibrillation is resumed in sinus rhythm, the right and left ears generally do not immediately resume rhythmical contraction, and are still in a state of stuttering, called atrial stuttering, so it is still necessary to anticoagulate for 4 weeks, which is the origin of anticoagulation in atrial fibrillation before 3 and after 4.
(However, now that the thrombus disappears or becomes significantly smaller in most people in 3 weeks of fatty nasal gag plague, the speculation is that although warfarin is not a thrombolytic drug, it disrupts the balance of thrombus deposition and dissolution, tipping the scales the other way.)
Next we cut off the right ventricular free wall as well, then we transparent the tricuspid valve and papillary muscle, and we expose the refreshing right atrial and right ventricular internal structures, and with these preparations we start to introduce the right atrial and right ventricular internal structures.
Right atrium chapter
The tricuspid valve is located at the atrial orifice and is anatomically divided into three parts: annulus, leaflets, and tendons. The tricuspid valve, as its name implies, has three valves: the anterior valve is connected to the anterior papillary muscle by tendons, the posterior valve is connected to the posterior papillary muscle by tendons, and there is a septal valve called the septum, which is connected to the medial papillary muscle and conus papillary muscle by tendons. Because there are three leaflets, the annulus at the atrioventricular opening is divided into three parts: the anterior tricuspid annulus 8, the posterior annulus 9, and the septal annulus 10, which is useful for remembering the septal annulus 10.
The fossa ovalis is one of the landmarks of the atrial septum, and I believe that all of you have found it. The fossa ovalis is very thin, only 2 mm thick, and radiofrequency ablation of atrial fibrillation is usually performed by piercing the fossa ovalis and raising the contrast guidewire to the left atrium for pulmonary venography, followed by femoral artery puncture and CARTO localization, and currently most of the fossa ovalis is not closed and we can seal it with a blocker without having to go through surgery again.
We note that the superior vena cava and inferior vena cava open to the right atrium, but oddly enough, we don’t find an upper or lower vena cava valve. So the question is, if there are no valves, wouldn’t the blood flow back up into the superior and inferior vena cava during atrial contraction?
The right atrium has evolved a muscle cuff at the upper and lower vena cava ports, which migrates to the upper and lower vena cava ports and contracts during atrial contraction, although it is not enough to close the vena cava ports, but it generates turbulence to counteract atrial pressure due to hydrodynamics. However, these muscle sleeves have P-cells with potential pacing function, and this is especially active in the left atrial pulmonary vein, which is often the culprit of atrial fibrillation, so this is the mechanism of current circumferential pulmonary vein ablation, which is far from the left atrial content, and now we are back to the right atrium.
Strictly speaking, the inferior vena cava used to have a venous valve, which was responsible for guiding blood flow into the foramen ovale during the embryonic period, and with the closure of the foramen ovale this inferior vena cava valve gradually degenerated, eventually degenerating into a raised structure called the European ridge connecting the mouth of the inferior vena cava to the anterior portion of the foramen ovale, which is also directly referred to as the inferior vena cava valve in some books. If the European ridge does not degenerate well enough, it is called the European flap, and if the degeneration fails, it even forms a mesh-like structure called the Charis net, which has 5 names for one thing.
Although Charis network is rare, but this is really a nasty thing, think about what is nasty – it will often be misdiagnosed by ultrasonographers as tricuspid valve prolapse, right atrial mucinous tumor, and even when installing pacemakers will also wind the guidewire, so we do elective PCI or electrophysiological examination conditions first check a two-dimensional probe to understand the anatomy of the heart It is still necessary to find out if there are any abnormalities.
This European ridge also has a role, in the posterior part of the European ridge is called the atrial septum connecting the left and right atria, for example, we just mentioned that the puncture in the foramen ovale is into the left atrium, while in front of the European ridge should be strictly called the atrioventricular septum, from this place the puncture is into the left ventricular outflow tract, this is a little difficult to understand Bug on a diagram.
Coronary sinus: most of the heart’s venous blood from the large heart vein, heart vein, small heart vein into the coronary sinus vein, through the coronary sinus finally back into the right atrium, the coronary sinus mouth lower edge of the coronary sinus valve, also known as Thesbesian valve, remember not all people have, only like bug such good character people have, the probability of 50%.
In the past, this anatomical structure was not taken seriously, but with the development of RF ablation and CRT, the coronary sinus has become a very important anatomical structure, because it is possible to measure the potential with a 10-pole CS electrode, and it is also the place where the posterior left ventricular venous electrode of CRT must pass.
Interestingly, the coronary venous blood flow will flow to the right atrium, and to image here, the contrast will flow back to the right atrium, so there is no way to image it, so we have to put a balloon at the mouth of the coronary sinus to block it, and we know that the left main trunk can not cut off the flow for too long. Closure of the coronary sinus is not so scary, the stereotype kills people.
There is a small bulge called Todaro’s tendon next to the European ridge, it is a fibrous structure, remember the tricuspid septum mentioned by Bug earlier, well Todaro’s tendon – tricuspid septum – coronary sinus opening, you must have guessed that an important anatomical structure Koch’s triangle is about to make its debut.
Koch’s triangle: Koch’s triangle is important in the mechanism of RF ablation and arrhythmia formation. Let’s first understand the definition of Koch’s triangle: The medial bevel of Koch’s triangle is the Todaro tendon, the lateral bevel is the tricuspid septal annulus, and the bottom edge is composed of a, b, and c. b is the diameter of the coronary sinus orifice, a is the shortest distance from the coronary sinus orifice to the Todaro tendon, and c is the shortest distance from the coronary sinus orifice to the tricuspid septal annulus.
As you can see, the top of the Koch triangle is just below the septum, so the height of the Koch triangle is from the coronary sinus orifice to the septum.
What is the significance of the Koch triangle?
Nowadays, electrophysiological studies have found that the fast and slow atrioventricular nodal tachycardia (AVNRT) pathways are not in the AV node, which would be a tragedy if they were, and that radiofrequency is helpless in AVNRT because the AV node cannot be ablated and is the softest and most untouchable part of the heart.
Unfortunately, many textbooks still use the same illustrations as before, which is misleading. Since the fast and slow pathways are within the Koch triangle, it is much safer to ablate in the vicinity of the Todaro tendon, which is generally the area of influence of the fast pathway, and the tricuspid septal annulus, which is the area of influence of the slow pathway.
In addition, this area is often the origin of the atrioventricular junctional rhythm, unlike the previous belief that it is below the bundle of Hirschsprung’s. Understanding this anatomical site and electrophysiological characteristics will help to understand the chapter of Clinical ECG on atrioventricular junctional rhythm by Mr. Huang Wan.
There is a posterior right atrial fossa between the inferior vena cava and the tricuspid annulus, also known as the right atrial isthmus, which is one of the thinner locations in the heart and can easily cause injury during electrophysiological examination.
The atrial flutter that folds back around the tricuspid annulus is one of the more common types of atrial flutter, and is also called isthmus-dependent atrial flutter because the isthmus is the pathway it must take, while the atrial flutter that folds back around the inferior vena cava and isthmus has a lower origin and is called low atrial flutter.
Right ventricle
Here is where we finally get to the right ventricle.
In ancient China, there was a man who refused to use the funnel for a long time and became famous in history, Pan Jun Naan Pan Cuo Xin Chon Hip Otter>菟涤依Ne矣懈雎┒凡浚遣亂徊抡飧雎┒酚Ω梅旁谀睦铮
Insects for everyone to unravel this mystery, look here, this is an inverted funnel, funnel is used to play soy sauce, in the right ventricle this funnel is responsible for collecting the right ventricular outflow tract of blood remittance to the pulmonary artery, because this funnel is shaped like a cone, so also called the arterial cone section.
The question again is what is the outflow tract and inflow tract? In addition to the outflow tract, the inflow tract is also called the arterial cone.
The following is an important point of knowledge of ECG, in the frontal electrical axis I, II, III, AVR, AVL, AVF detection current direction as shown in the figure, when the ventricular depolarization integrated vector in the frontal projection direction and detection current direction, QRS main wave up, and vice versa main wave direction down.
If the depolarization excitation comes from the sinus node or point A (outflow tract), then the direction of depolarization is the same as the general direction of II, III, and AVF, so the main wave direction of QRS is upward in II, III, and AVF, and if it comes from point B of the inflow tract, it is conceivable that the cardiac depolarization is from downward to upward, which is opposite to the general direction of II, III, and AVF, so the main wave direction of QRS is downward in II, III, and AVF. It is likely to be a premature ventricular tachycardia or ventricular tachycardia originating from the inflow tract.
Similarly, the ventricular pacing electrodes of early pacemakers are usually placed in the inflow tract because the columnar muscles are interspersed in this area, and if the pacemaker electrode head is barb-shaped, it can be easily fixed passively and installed conveniently, but the location of this area is low, the ventricular contraction is bottom-up, and the QRS wave width is not physiological;
Therefore, many new pacemakers place the pacing electrodes in the high outflow tract, but this area is smooth and cannot be fixed passively.
The Y-shaped flat muscle bulge in the right ventricle is very striking. This “y” is divided into three parts: c is the septal band, a is the anterior foot of the septal band, and b is the posterior foot of the septal band, which extends downward to the septal meatus, the largest meatus in the heart. The septum extends downward to the septal meatus, the largest meatus of the heart. The right bundle branch, as we call it, goes in there, and the end of the septal meatus is connected to the anterior papillary muscle.
Here are two abstract and unimportant structures, and you read that right – unimportant. Although unimportant, but because these two names are really too high, must be removed first and then. These two structures are the supraventricular ridge and the boundary ridge, and they are abstract because the heart is often cut into two parts in anatomy, and it is difficult to express a structure across these two positions or at a turning point in the diagram, so without further ado, let’s go to the diagram.
The ventricular septum is the most confusing part of the naming process, so I’m going to introduce it from the simple to the complex.
The septum is divided into one; the classical anatomical division method: the word “yah” is used as the natural potential division range, divided into sinus, trabecular and funnel. There are medial papillary muscles above the sinus part, conical papillary muscles above the funnel part for tricuspid septal valve attachment, and myocardial trabeculae and meatus above the trabecularized part.
The septal division II: The classical pathology division is divided into membrane and muscle. If there is no muscle, it is called the membrane part, and if there is muscle, it is the muscle part. The membrane part has a small area of influence, as shown in the figure, it is the thinnest part of the ventricular muscle, and it is the best place for ventricular septal defect to occur.
Ventricular septal division III: classical blood supply division This is a very familiar division of the septum into the anterior and posterior edges, which is often referred to as the anterior and posterior septum, and sometimes called it the upper and lower septum, so many ways of expression, Bug said duck pears. The anterior interventricular septum is supplied by the anterior descending branch, and the posterior interventricular septum is supplied by the posterior descending branch, so this division is also applicable to infarct localization (the left atrium and left ventricle chapter will be mentioned).
However, we need to know that this division leaves out the upper edge of the ventricular septum: the upper edge is a peculiar terrain, adjacent to many, and has an unusually complex anatomy (it consists of 3 parts, which Bug will not expand here).
The septum is divided into four: the upper part of the septum, the middle part of the septum, and the lower part of the septum, that is, the above two divisions into three divisions, which we will know at a glance, not to expand.
The septum is divided into upper, middle, and lower segments, which will be explained in detail in the heart ultrasound section anatomy.
The septum is a common part of the right and left ventricles, and the anatomy of the right ventricle ends here and the anatomy of the left ventricle begins here. As the six worlds reincarnate and live on, stay tuned for “Notes on Cardiac Anatomy: Left Atrium and Left Ventricle”, where we will start with the ischemic localization of the myocardium.