The heart receives blood through four major vessels - the superior and inferior vena cava and the right and left pulmonary veins. It pumps blood out through two major vessels - the pulmonary trunk and aorta. The heart has four chambers - two upper atria and two lower ventricles. It is surrounded by layers including the pericardium. The heart lies in the middle mediastinum and has four surfaces and four borders defined by its chambers. Valves between the chambers include the tricuspid, pulmonary, mitral and aortic valves. The heart has a complex electrical conduction system to coordinate contractions. Arteries supplying the heart include the coronary arteries while veins draining it include the cardiac veins.
2. THE HEART
• The heart, slightly larger than a clenched fist.
• The right side of the heart receives
poorly oxygenated blood from the body
through the SVC and IVC and pumps
it through the pulmonary trunk to the lungs for
oxygenation.
• The left side of the heart receives
well-oxygenated blood from the
lungs through the pulmonary veins and pumps it into the aorta for
distribution to the body.
3. POSITION
• Lies within the pericardium in middle mediastinum.
• Located in the mediastinum
• Behind body of the sternum
• Between 2nd and 6th intercostal cartilages
• Infront of 5th -8th thoracic vertebrae.
• Apex –
• Located at the 5th intercostal space
4.
5. Four Grooves
• Coronary sulcus
Which marks the divison between atria and ventricles,contains the trunks of
the coronary vessels and completely encircles the heart.
• Interatrial groove
Separates the 2 atria and is hidden by the pulmonary trunk and aorta in
front.
• Interventricular grooves
Anterior and posterior-mark the division between ventricles(which separates
the RV from the LV) the 2 grooves extend from the base of the ventricular
portion to a notch called: the cardiac apical incisure.
6.
7. Coverings of the heart
• Pericardium – a double-walled sac around the heart composed of:
• Fibrous pericardium – tough, loose-fitting, inelastic
• Serous pericardium
• Parietal layer: lines the inside of the fibrous pericardium
• Visceral layer: adheres to outside of the heart
• Pericardial space: between parietal and visceral layer
• Filled with 20-25mL of pericardial fluid
• Decreases friction
8.
9. Layers of heart wall
• The wall of the heart consists of three layers.
from superficial to deep they are:
1. Epicardium:
-a thin external layer (mesothelium) formed by the visceral
layer of serous pericardium.
2. Myocardium:
- a thick middle layer composed of cardiac muscle.
-Intercalated disks contain many gap junctions
-Allow cardiac muscle cells to function as a single unit
syncytium
3.Endocardium:
- a thin internal layer (endothelium and subendothelial
connective tissue) or lining membrane of the heart that also
covers its valves.
10. The Function of the Pericardium:
• Protects and anchors the heart
• Prevents overfilling of the heart with blood
• Allows for the heart to work in a relatively friction-free
environment
11. Development of heart and pericardium.
• The primordial heart tube invaginates the double-layered pericardial sac
(somewhat like placing a hot dog in a bun).
• The primordial heart then loops ventrally, bringing the primordial arterial and
venous ends of the heart together and creating the transverse pericardial sinus
between them.
• The veins expand and move apart. The pericardium is reflected around them to
form the boundaries of the oblique pericardial sinus.
12. • Transverse Pericardial sinus
Posterior to ascending aorta
and pulmonary trunk, anterior
to superior vena cava and left atrium.
• Oblique pericardial sinus
Cul-de-sac, posterior to heart,
bounded by pulmonary veins on either side
13. The arterial supply of the pericardium
• Mainly from the pericardiacophrenic
artery, a branch of the internal thoracic
artery, which may accompany or
parallel the phrenic nerve
to the diaphragm.
14. • Smaller contributions of blood to the pericardium come from the
musculophrenic artery, a terminal branch of the internal thoracic
artery.
• The bronchial, esophageal, and superior phrenic arteries from the
thoracic aorta.
• The coronary arteries, supplying only the visceral layer of serous
pericardium.
15. The venous drainage of the pericardium
Pericardiacophrenic veins, tributaries of
the brachiocephalic (or internal thoracic)
veins.
Variable tributaries of the azygos venous
system.
16. The nerve supply of the pericardium
• Phrenic nerves (C3-C5)—a primary
source of sensory fibers; pain sensations
conveyed by these nerves are
commonly referred to the skin (C3-C5
dermatomes) of the top of the shoulder
of the same side.
• Vagus nerves (CN X)—function
uncertain.
• Sympathetic trunks—vasomotor
17. ORIENTATION OF HEART
• The heart and roots of the great vessels
within the pericardial sac are related
anteriorly to the sternum, costal cartilages,
and the medial ends of the third to fifth ribs
on the left side.
• The heart and pericardial sac are situated
obliquely, about two thirds to the left and
one third to the right of the median plane.
The heart is shaped like a tipped-over, three-
sided pyramid with an apex, base, and four
surfaces.
18. The apex of the heart
-Is directed anteriorly and to the left.
-formed by the inferolateral part of the left ventricle.
- located posterior to the left fifth intercostal space
in adults
- usually 9 cm from the median plane.
- where the sounds of mitral valve closure are
maximal (apex beat);
- the apex underlies the site where the heartbeat
may be auscultated on the thoracic wall.
19. The base of the heart :
- the heart's posterior aspect.
-formed mainly by the left atrium, with a lesser contribution by the right
atrium.
-Faces posteriorly toward the bodies of vertebrae T6-T9, and is separated
from them by the pericardium, oblique pericardial sinus, esophagus, and
aorta.
-Extends superiorly to the bifurcation of the pulmonary trunk and inferiorly
to the coronary groove.
-Receives the pulmonary veins on the right and left sides of its left atrial
portion and the superior and inferior venae cavae at the superior and
inferior ends of its right atrial portion
20.
21. SURFACES OF THE HEART
It has four surfaces
1.Anterior (sternocostal) surface
- formed mainly by the right ventricle.
2.Diaphragmatic (inferior) surface
- formed mainly by the left ventricle and partly by the right ventricle; it is
related to the central tendon of the diaphragm.
3.Left pulmonary surface
- consists mainly of the left ventricle; it forms the cardiac impression of the
left lung.
4.Right pulmonary surface
-formed mainly by the right atrium.
22.
23. Borders of the heart
It has four borders
1.Right border (slightly convex)
• formed by the right atrium and extending
between the SVC and the IVC
2.Inferior border (nearly horizontal)
• formed mainly by the right ventricle and
only slightly by the left ventricle
3.Left border (oblique)
• formed mainly by the left ventricle and
slightly by the left auricle
24. 4.Superior border
• formed by the right and left atria
and auricles in an anterior view
• the ascending aorta and
pulmonary trunk emerge from the
superior border, and the SVC enters
its right side.
• Posterior to the aorta and pulmonary trunk
and anterior to the SVC, the superior border forms the inferior
boundary of the transverse pericardial sinus.
25. CHAMBERS OF THE HEART
• The heart has four chambers
• Atria – two superior chambers
• “Receiving chambers”
• Blood from veins enters atria
• Ventricles – two inferior chambers
• “pumping chambers”
• Thick muscular walls to increase force of pumping action
• Left > right
• Separated by interventricular septum
26. Right atrium
• The right atrium forms the right border of the
heart.
• Receives venous blood from the SVC, IVC, and
coronary sinus.
• The coronary sinus lies in the posterior part of
the coronary groove and receives blood from the
cardiac veins.
• A smooth, thin-walled posterior part : the sinus
venarum, on which the SVC, IVC, and coronary
sinus open, bringing poorly oxygenated blood
into the heart
• A rough, muscular wall composed of pectinate
muscles with a vertical ridge, the crista
terminalis which seperates it from smooth
walled parts of right atrium
27. Opening to the right atrium
• SVC opens into its superior part, at the level of
the right third costal cartilage
• IVC opens into the inferior part, almost in line
with the SVC at approximately the level of the
fifth costal cartilage
• coronary sinus opens between the right
atrioventricular (AV) orifice and the IVC orifice
• right AV orifice lies anterior to IVC opening and
is guarded by tricuspid valve.
• The interatrial septum, separating the atria, has
an oval, thumbprint-size depression, the oval
fossa , a remnant of the oval foramen and its
valve in the fetus.
28. • Fetal remnants of right atrium
- Rudimentary valve of inferior vena cava
- Fossa ovalis & Anulus ovalis: lie on atrial septum.
- Fossa ovalis is a shallow depression, which is site
of foramen ovale in fetus. Anulus ovalis forms
upper margin of fossa. Floor of the fossa
represents persistent septum primum of heart of
embryo, and anulus is formed from lower edge of
septum secundum.
29. Right ventricle
• The right ventricle forms
- the largest part of the anterior surface of
the heart.
- a small part of the diaphragmatic surface.
- almost the entire inferior border of the
heart.
• Superiorly it tapers into
- an arterial cone; the conus arteriosus
(infundibulum), which leads into the
pulmonary trunk.
• The interior of the right ventricle has
irregular muscular elevations called
trabeculae carneae.
30. • It communicates with right atrium through atrioventricular orifice
and with pulmonary trunk through pulmonary orifice.
• Its cavity becomes funnel shaped near pulmonary orifice called
(infundibulum).
• Walls of right ventricle are much thicker than those of right atrium
and show several internal projecting ridges formed of muscle bundles
trabeculae carneae.
• One type of these trabeculae carneae are Papillary muscles: which
project inward, being attached by their bases to ventricular wall; their
apices are connected by fibrous chords (chordae tendineae) to cusps
of tricuspid valve.
31. Tricuspid valve
• Guards atrioventricular
orifice and consists of 3 cusps formed
by a fold of endocardium with
some connective tissue enclosed:
Anterior, Septal & Inferior (posterior)
cusps.
• Bases of cusps are attached to
fibrous ring of heart skeleton, whereas
their free edges & ventricular surfaces
are attached to chordae tendineae.
• When ventricle contracts, papillary muscles contract
and prevent cusps from being forced into atrium and
turning inside out as intraventricular pressure rises. Chordae tendineae of one papillary
muscle are connected to adjacent parts of two cusps.
32. Pulmonary valve
• Guards pulmonary orifice and
consists of 3 semilunar cusps
formed by folds of endocardium
with some connective tissue enclosed.
• Open mouths of cusps are
directed upward into pulmonary trunk.
• No chordae or papillary muscles
are associated with these cusps;
attachments of sides of cusps to
arterial wall prevent cusps from prolapsing
into ventricle. At root of pulmonary trunk are 3 dilatations (sinuses)
each one is situated external to each cusp.
33. Left Atrium
• It consists of a main cavity and a left
auricle.
• Left atrium is situated behind
right atrium and forms greater part
of base (posterior surface) of heart.
• Behind it lies oblique sinus of
serous pericardium,and fibrous
pericardium separates it from esophagus.
• Interior of left atrium is smooth,
but left auricle possesses muscular ridges.
34. • Openings into the Left Atrium:
• Four pulmonary veins: two from each
lung, open through posterior wall with no
valves.
• Left Atrioventricular Orifice: is guarded by
mitral valve.
35. Left Ventricle
• It communicates with left atrium through
atrioventricular orifice and with aorta through
aortic orifice.
• Walls of left ventricle are three times thicker
than those of right ventricle.
• In cross section, left ventricle is circular;
• Right is crescentic because of bulging of
ventricular septum into cavity of right
ventricle.
• There are well-developed trabeculae carneae,
two large papillary muscles. Part of ventricle
below aortic orifice is called aortic vestibule.
36. Mitral valve
• Guards atrioventricular orifice.
• It consists of two cusps, one anterior
and one posterior, which have a
structure similar to that of tricuspid
valve.
• Anterior cusp is the larger and
intervenes between atrioventricular
and aortic orifices.
37. Aortic valve
• Guards aortic orifice and is similar to
pulmonary valve.
• It has three semi lunar cusps-anterior,and
right and left posterior.
• Above each cusp is a localized dilatation or
sinus. These are known as the sinuses of
Valsalva.
• Anterior aortic sinus gives origin to right
coronary artery, and left posterior sinus
gives origin to left coronary artery.
• No artery arises from the posterior aortic
(noncoronary) sinus.
38. Structure of the heart skeleton
• consists of fibrous rings that surround
atrioventricular, pulmonary,and aortic orifices
and are continuous with membranous upper
part of ventricular septum.
• Fibrous rings around atrioventricular orifices
separate muscular walls of atria from those of
ventricles but provide attachment for muscle
fibers.
• Fibrous rings support bases of valve cusps and
prevent valves from stretching and becoming
incompetent. Skeleton of heart forms
basis of electrical discontinuity between atria
and ventricles
39. Conducting System of the Heart:
• Sinuatrial Node: is located in wall of right atrium in upper part
of sulcus terminalis just to right of opening of superior vena
cava.
• Atrioventricular Node: is strategically placed on lower part of
atrial septum just above attachment of septal cusp of
tricuspid valve.
• Atrioventricular Bundle of His:
It descends through fibrous skeleton of
heart behind septal cusp of tricuspid valve
to reach upper border of muscular
part of septum, then divides into
two branches, one for each ventricle.
A.Right bundle branch (RBB)
B.Left bundle branch (LBB) Subendocardial plexus
of Purkinje fibers:
40. External Heart: Major Vessels of the Heart
(Anterior View)
• Vessels returning blood to the heart include:
1. Superior and inferior venae cava.
2. Right and left pulmonary veins
• Vessels conveying blood away from the heart
include:
1. Pulmonary trunk, which splits into right and left
pulmonary arteries
2. Ascending aorta (three branches) –
a. Brachiocephalic
b. Left common carotid
c. Subclavian arteries
41. External Heart: Vessels that Supply/Drain the
Heart (Anterior View)
• Arteries
-right and left coronary (in atrioventricular
groove), marginal, circumflex, and anterior
interventricular arteries
• Veins
-small cardiac, anterior cardiac, and great
cardiac veins
42. External Heart: Major Vessels of the Heart
(Posterior View)
• Vessels returning blood to the heart include:
1. Right and left pulmonary veins
2. Superior and inferior venae cavae
• Vessels conveying blood away from the
heart include:
1. Aorta
2. Right and left pulmonary arteries
43. External Heart: Vessels that Supply/Drain the
Heart (Posterior View)
• Arteries
- right coronary artery (in atrioventricular groove) and the posterior
interventricular artery (in interventricular groove)
• Veins
-great cardiac vein, posterior vein to left ventricle, coronary sinus, and
middle cardiac vein
44. Arterial Supply of Heart
• It is provided by right and left coronary arteries, which
arise from ascending aorta immediately above aortic
valve
• Coronary arteries and their major branches are
distributed over surface of heart, lying within
subepicardial connective tissue.
• Right coronary artery arises from anterior aortic sinus of
ascending aorta & runs forward between pulmonary
trunk & right auricle.
• It descends almost vertically in right atrioventricular
groove, and at inferior border of heart it continues
posteriorly along atrioventricular groove to anastomose
with left coronary artery in posterior interventricular
groove.
• It supplies right ventricle and inferior wall of left
ventricle.
45. Branches of right coronary
artery:
1.Right conus artery: supply pulmonary
conus
2.Atrial branches
• supply anterior and lateral surfaces of right
atrium. One branch supplies posterior
surface of both right and left atria.
• Artery of sinuatrial node supplies node
and right and left atria; in 35% of
individuals it arises from left coronary
artery.
46. 3.Ventricular Branches:
• Anterior ventricular branches: supply anterior
surface of right ventricle.
• Marginal branch: is the largest & runs
along lower margin of costal surface to reach apex.
• Posterior ventricular branches: supply
diaphragmatic surface of right ventricle.
• Posterior interventricular (descending) artery: runs
in posterior interventricular groove. It supply
inferior wall & posterior part of ventricular septum.
• Large septal branch supplies AV node.
47. Arterial Supply of Heart
• Left coronary artery supplies major part of heart, including greater part of left
atrium, left ventricle, and ventricular septum.
• It arises from left posterior aortic sinus of ascending aorta and passes forward
between pulmonary trunk and left auricle.
• It then enters atrioventricular groove & divides into an anterior interventricular
(descending)branch & circumflex branch.
• Anterior interventricular (descending) branch: runs downward in anterior
interventricular groove. In most individuals it passes around apex of heart to
enter posterior interventricular groove & anastomoses with terminal branches of
right coronary artery.
• It supplies right & left ventricles with numerous branches that also supply
anterior part of ventricular septum. One of these ventricular branches (left
diagonal artery) may arise directly from trunk of left coronary artery
• A small left conus artery supplies pulmonary conus.
48.
49. Branches of the anterior descending artery
• Septal branches
• Diagonal branches that run over the anterolateral wall of the left ventricle
supplying it
• A branch to the right ventricle(occasionally).
Branches of the left circumflex artery
• Obtuse marginal branches , which supple the lateral wall of the left ventricle.
• Atrial branches.
Coronary Artery Anastomoses between terminal branches of right & left coronary
arteries exist, but not large to provide an adequate blood supply to cardiac muscle
if one of large branches becomes blocked. A sudden block of one of larger
branches of either coronary artery usually leads to myocardial infarction, although
sometimes collateral circulation is enough to sustain muscle
50.
51. Variations in the Coronary Arteries
• Four per cent of people have a third, the posterior coronary artery.
• In rare cases, a person will have one coronary artery that runs around the root of the aorta
• Occasionally, a coronary artery will exist as a double structure (i e there are two arteries, parallel to
each other, where ordinarily there would be one)
Coronary artery dominance
• The artery that supplies the posterior descending artery (PDA) and the posterolateral artery (PLA)
determines the coronary dominance.
• In effect, the artery supplying the posterior and lateral wall of the left ventricle is the dominant
artery.
• If the right coronary artery (RCA) supplies both these arteries, the circulation can be classified as
right-dominant.
• If the circumflex artery (CX), a branch of the left artery, supplies both these arteries, the circulation
can be classified as left-dominant.
• If the RCA supplies the PDA and the CX supplies the PLA, the circulation is known as co-dominant.
• Approximately 60% of the general population are right dominant, 25% are co-dominant, and 15% are
left dominant.
52. Blood Supply of the papillary muscles.
• The papillary muscles tether the mitral valve and the tricuspid valve
to the wall of the heart .
• The anterolateral papillary muscle more frequently receives two
blood supplies: left anterior descending (LAD) artery and the left
circumflex artery (LCX) It is therefore more frequently resistant to
coronary ischaemia.
• The posteromedial papillary muscle is usually supplied only by the
PDA. This makes the posteromedial papillary muscle significantly
more susceptible to ischaemia and therefore, myocardial infarction
involving the PDA is more likely to cause mitral regurgitation.
53. Venous Drainage of the Heart
• Most blood from heart wall drains into
right atrium through coronary sinus, which
lies in posterior part of atrioventricular
groove and is a continuation of great
cardiac vein.
• Middle cardiac vein ascends in the
posterior interventricualr groove.
• Small cardiac veins accompany the
marginal branches of the RCA on the
inferior surface of the heart and then runs
posteriorly in the right atrioventricular
groove to enter the right side of the
coronary sinus.
54. • Left posterior ventricular vein accompanies the
obtuse marginal of the LCA, running up the
posterior aspect of the left ventricle to drain into
coronary sinus.
• The anterior cardiac veins drain much of the
anterior surface of the heart and drain into the
anterior wall of the right atrium directly.
• Several small veins , the venae cordis
minimae,drain directly into cardiac chambers.
55. Nerve Supply of Heart
• Heart is innervated by sympathetic and
parasympathetic fibers of autonomic nervous
system via cardiac plexuses situated below arch
of aorta.
• Sympathetic supply arises from cervical & upper
thoracic portions of sympathetic trunks, and
parasympathetic supply comes from vagus
nerves.(CN X)
• Sympathetic fibers terminate on SA & AV nodes,
cardiac muscle fibers & coronary arteries. These
nerves results in cardiac acceleration, increased
contraction of cardiac muscle, and dilatation of
coronary arteries.
• Parasympathetic fibers terminate on SA & AV
nodes and on coronary arteries. These fibers
results in a reduction in rate and force of
contraction of heart and a constriction of coronary
arteries
56. IMAGING TECHNIQUES
• Radiology of the heart
1.Chest radiography
• The cardiac contour is seen on the frontal and lateral chest film
Posteroanterior films are preferred to anteroposterior ones as the
heart, being anterior, is closer to the film and is not magnified to the
same extent as with anteroposterior films.
• The cardiothoracic ratio, usually less than 50%,maybe up to
55% in Asian and Afro-Caribbean subjects and up to 60% in infants.
57.
58. • The position of the valves may be deduced on PA and lateral films in
relation to the cardiac outline or the sternum and ribs. The aortic and
mitral valves are the most important to recognize, as they are most
often affected by disease.
• On a PA chest radiograph the valves lie close to a line from the left
atrium to the lowest point of the right heart border.
• On a lateral view the pulmonary and aortic valves lie just above,and
the mitral and tricuspid valves just below, a line drawn from T5 to
the apex of the heart
• The lowest part of the aortic valve is very close to the anterior part of
the mitral valve, where they are anatomically in fibrous continuity
59.
60. 2.Fluroscopy
• The heart and its valves may be assessed by fluoroscopy. If the valves
are calcified (usually pathologically) they may be distinguished by
their characteristic motion as well as their location. The aortic valve
has a to-and-fro motion in the plane of the ascending aorta, that is,
upwards, backwards and to the right The mitral valve has a circular as
well as a to-and-fro motion in the left anterior oblique plane of the
left atrium and ventricle.
61. • 3.Echocardiography
• Two-dimensional echocardiography uses ultrasound to
image the heart.
• A subcostal or intracostal window may be used and
images may be obtained in any plane
• Longitudinal images through the outflow tracts are
usually obtained, as well as cross-sectional images
through the valves and chambers.
• Ultrasound is probably the best modality for imaging
the internal anatomy of the heart, the walls, chambers
and valves.
• The movement of the walls and valves may also be
assessed dynamically throughout the cardiac cycle.
• Transoesophageal echocardiography allows much
closer inspection of the heart because of the close
apposition of the left atrium to the anterior wall of the
distal oesophagus, without intervening air or lung.
62. 4. Angiocardiography
• This technique involves the
injection of contrast directly into
the heart chambers via a pigtail
catheter, which is usually
introduced through the femoral
artery or vein for the left and right
chambers, respectively.
• The chambers are recognized by
their position and characteristic
configuration.
63. 5.Coronary angiography
• Involves selective catheterization of
the coronary arteries.
• A small volume of contrast is injected
and images may be obtained in lateral,
anterior oblique and AP projections.
• There is individual variation in the
branches of the coronary arteries,
which are demonstrated from case to
case.
• This is due both to anatomical
variation and technical factors.
64. 6.Nuclear medicine
• Nuclear medicine studies are used mainly for functional
assessment of the heart, which in clinical practice is often
more important than the demonstration of the anatomy ,
• Thallium-201 ( 201 Th) and technetium-99m ( 99m Tc)-
labelled MIBI (2-methoxy isobutyl isonitrile) are taken up by
normally perfused myocardium, and images obtained by
gamma camera show the heart.
• The use of SPECT (single photon emission CT) allows images
to be constructed in any plane – usually with three sets of
images – along the short cardiac axis (at right-angles to the
long axis of the heart), and along the vertical and horizontal
long axes,
• It also improves the target:background ratio, as neither
radiopharmaceutical agent is taken up exclusively by the
myocardium.
• Other functional information on ventricular filling, ejection
fraction and so on may be obtained by blood-pool imaging
using 99m Tc-labelled red blood cells and electrocardiogram
(ECG)-gated acquisition of data
65. 7.Computed Tomograph
• CT scanning shows the heart and vessels in cross-section.
• The pericardium may be identified between epicardial and mediastinal
fat.
• Dynamic scans obtained during intravenous infusion of contrast
demonstrate the cardiac chambers and vessels to greater advantage.
• ECG gating allows images to be acquired during the same part of the
cardiac cycle, thus reducing motion artefacts and providing better
images.
• The development of multislice CT, acquired with 64-slice single and
dual tube CT scanners, allows improved spatial and temporal resolution
and hence improved visualization of the coronary arteries.
• By acquiring imaging data at reproducible points in the cardiac cycle
using ECG gating, by slowing the cardiac rate to less than 70 beats per
minute using betablockers and by rapidly acquiring information using
multiple slices, the effects of cardiac movement are overcome.
• Preprocedural sublingual nitrates produce coronal dilatation which in
combination with rapid contrast infusion by a pump injector produce
dramatic contrast filling of the main coronary vessels.
66. • By acquiring data in isotropic voxels, images can
be reconstructed in innumerable planes to allow
interrogation of the main coronary arteries as
they branch and track in coronal, sagittal, axial
and oblique planes.
• Coronary calcium score.
• Non-contrast cardiac CT is employed to identify
coronary arterial wall calcification.
• The presence of wall calcification is used as an
indirect marker of atherosclerosis and plaque.
• The more calcification there is the greater the
likelihood of underlying significant coronary
artery atherosclerotic disease.
67. 8. Magnetic resonance imaging
• The applications for MRI in cardiac radiology are
steadily increasing.
• Acquisition of images is gated to the ECG to overcome
motion artefact, and faster scan times have improved
image quality.
• The cardiac chambers, valves and major vessels may
be imaged in any plane to give information previously
only obtainable with cardioangiography, and with the
added advantage of demonstrating the soft tissues.
• The pericardium is shown as a dark line 1 – 2 mm
thick.
• In general non-contrast studies are employed to assess
cardiac wall morphology In contrast, bolus tracking
following contrast injection is employed to image the
coronary arterial circulation
68. 9. PET CT
• Normal cardiac muscle concentrates or consumes
injected
18-fluorodeoxyglucose reflecting normal pulsatility
and cardiac muscular contractions.
• Targeted cardiac PET CT scanning allows detection
of metabolically inactive sites of infarcted muscle.
• When combined with CT coronary angiography, it
may show areas of salvageable hibernating
myocardium, which shows persistent metabolic
activity despite loss of vascular supply
demonstrated at CT angiography.
69.
70. References
• Anatomy for diagnostic imaging –Stephanie Ryan, Michelle McNicholas, Stephen
Eustace
• Essential clinical anatomy – keith L.Moore, Anne M.R. Agur, Arthur F. Dalley
• Other sources via the internet
Notas do Editor
1.The ear-like right auricle is a small, conical muscular pouch that projects from the right atrium, increasing the capacity of the atrium as it overlaps the ascending aorta. The primordial atrium is represented in the adult by the right auricle. The definitive atrium is enlarged by incorporation of most of the embryonic venous sinus (L. sinus venosus).
2. The coronary sinus is also a derivative of the embryonic venous sinus. The part of the venous sinus incorporated into the primordial atrium becomes the smooth-walled sinus venarum of the adult right atrium. The separation between the primordial atrium and the sinus venarum is indicated externally by the sulcus terminalis (terminal groove) and internally by the crista terminalis (terminal crest). The interior of the right atrium has (Figs. 1.29 and 1.30):
A thick muscular ridge, the supraventricular crest, separates the ridged muscular wall of the inflow part of the chamber from the smooth wall of the conus arteriosus or outflow part of the right ventricle. The inflow part of the right ventricle receives blood from the right atrium through the right AV (tricuspid) orifice, located posterior to the body of the sternum at the level of the fourth and fifth intercostal spaces. The right AV orifice is surrounded by a fibrous ring (part of the fibrous skeleton of heart) that resists the dilation that might otherwise result from blood being forced through it at varying pressures.