2. Outline
• Heart and Pericardium
• Heart Chambers
• Coronary Circulation
• Cardiac Conduction System
• Q & A
3. Heart and Pericardium
• Located in middle mediastinum, bounded by the pericardial sac.
• Pericardium encapsulates the heart and base of the great vessels,
• Composed of a fibrous (outer) and serous layer
• Serous pericardium is further divided into parietal and visceral layers
• Space between the two: Pericardial cavity.
4. Clinical Relevance
• Somatic sensation to pericardium: Phrenic nerves (C3‐5)
• Pass in the fibrous pericardium to innervate the diaphragm:- Pericardial pain
may be referred to the shoulder
5. Pericarditis
• Etiology is multifactorial including infection, post MI, malignancy and
autoimmune.
• Clinical features:
• Sharp central chest pain exacerbated by movement and lying down and
relieved by sitting forward. May be referred to shoulder/neck.
• Auscultation: pericardial friction rub, typically at left lower sternal edge on
end expiration with the patient leaning forward.
• Key investigation is an ECG: often shows saddle‐shaped ST elevation
in the early stages.
• Differentiating this from a MI is clearly crucial.
*Abnormalities not normally illustrated on a CXR
6.
7. Pericardial effusion
• Pericardial cavity normally contains ± 50cc fluid.
• Excess: Pericardial effusion, reducing ventricular filling.
• If accumulates slowly, able to support up to 2L, but if rapidly occurs,
even 200cc can cause tamponade
• Echocardiography is the key investigation for diagnosis.
• Most cases resolve spontaneously but a pericardiocentesis may be required
to alleviate tamponade.
8. Heart Chambers
• 2 atrias & 2 ventricles.
• Externally, the coronary sulcus separates atria from ventricles and
contains several vessels: Right coronary artery & Circumflex branch of
Left coronary artery.
• Delineating the L & R ventricles are the anterior & posterior
interventricular sulci, which also contain major vessels:
• Anteriorly: Anterior interventricular artery and great cardiac vein
• Posteriorly: Posterior interventricular artery and middle cardiac vein.
• Internally: Separated by interatrial and interventricular septum
9.
10.
11. • Right atrium:
• Forms right anterolateral border of the heart.
• Receives deoxygenated blood from the superior & inferior venae cava and coronary
sinus.
• Interatrial wall is fossa ovalis – embryological remnant of foramen ovale.
• Right ventricle:
• Forms majority of the anterior border of the heart.
• Presence of multiple trabeculae carneae (muscular strip). 3 of these strips attach to
the tricuspid valve to prevent eversion of its cusps during ventricular contraction.
These are the papillary muscles, and are connected to the tricuspid valve via the thin
fibre‐like chordea tendineae.
• Outflow tract, passing into pulmonary trunk, is smooth, and termed, conus
arteriosus. Via the pulmonary valve, also composed of three cusps.
12.
13. • Left atrium:
• Large proportion of the posterior aspect of the heart.
• Receives oxygenated blood from the four pulmonary veins.
• Left ventricle:
• Left anterolateral and diaphragmatic surfaces of the heart.
• Similarly, the inflow tract is rough compared to.
• Compared to right, only 2 papillary muscles are present to prevent backflow of blood
through the mitral valve.
• Aortic valve placed posterior to its pulmonary counterpart.
• Right & left coronary arteries originate from the left and right sinuses, which are the
space between the aorta and the aortic valve. (Allows coronary flow when the valve
closes during diastole)
14.
15. Clinical relevance
1. Auscultation
• The heart sounds heard on auscultation of the precordium relate to
valve closure.
• 1st heart sound (“lubb”): closure of the AV valves, (tricuspid & mitral),
at beginning of systole.
• 2nd sound (“dubb”): closure of semilunar valves at end of systole &
beginning of diastole.
• Cardiac arrhythmias & murmurs can be identified and diagnosed
when placed in the context of the cardiac cycle.
16. 2. Valvular heart disease
• Regurgitation (backflow of blood secondary to inadequate closure)
• Stenosis (insufficient valvular opening causing obstruction to flow).
• May arise in any valve, but mitral and aortic valves are most commonly
affected.
• Mitral valve
• Combined stenosis and incompetence is often present, although one may be more
prominent. Leads to dysfunctional blood flow causing left ventricular hypertrophy,
increased pulmonary pressure, pulmonary oedema and left atrial dilatation.
• Mitral stenosis produces mid‐diastolic murmur, whereas mitral
regurgitation produces pansystolic murmur.
17. • Aortic valve
• Aortic stenosis produces ejection systolic murmur heard in the aortic area
with/without radiation to neck.
• Aortic regurgitation produces a diastolic murmur
• Right sided valve disease
• Tricuspid/pulmonary valve disease often result of infection (rheumatic fever
and infective endocarditis), or congenital malformations.
18. Coronary Circulation
• Right & left coronary arteries arise from the aortic sinuses providing
oxygenated blood to cardiac tissues.
• Right coronary artery:
• Passes inferiorly in the coronary sulcus between the right atrium and
ventricle.
• Along its course, branches to provide the atrial and SA nodal branch and the
right marginal branch.
• Terminates as the posterior interventricular branch in the posterior
interventricular sulcus.
• Supplies: Right atrium & ventricle, the SA and AV nodes, proportion of
the interatrial and interventricular septum.
19. • The left coronary artery:
• Enters the coronary sulcus, before terminating as the anterior
interventricular (anterior interventricular sulcus) and circumflex arteries
(coronary sulcus).
• This allows the left coronary to supply the left atrium and ventricle and a
proportion of the interventricular septum.
• Venous drainage:
• Great, middle, small and posterior cardiac veins
• Drain into the coronary sinus, draining into right atrium.
20.
21. Cardiac Conduction System
• Contraction of cardiac muscle occur independently as a result of the presence of an
internal conduction system which sends electrical impulses to the myocardium.
• Begin at SA node. Located in the right atrium close to the entrance of the superior vena
cava.
• Result in contraction of the atria.
• Electrical signal then passes to the AV node, which is located in the atrioventricular
septum near the tricuspid valve.
• Acts as starting point for signal transmission to the ventricles.
• Extending from AV node is atrioventricular bundle. This splits into the right and left
bundle branch which both pass in their corresponding side along the interventricular
septum, before terminating as the Purkinje fibres.
• This creates a coordinated spread of excitation along the ventricles with subsequent
effective myocardial contraction
22.
23. Clinical relevance
• Coronary artery disease results in myocardial ischaemia and
infarction.
• Site occlusion determines area of infarction, and damage can be
assessed by ECG monitoring.
• The following ECG changes may be seen following a MI:
• Anterior MI
• ST elevation in V1 – V3
• Inferior MI
• ST elevation in II, III and AVF
24. • Lateral MI
• ST elevation in I, AVL and V5/6
• Posterior MI
• ST depression in V1 – V3
• Dominant R wave
• ST elevation in V5/6
25. Q & A
• With regards to the pericardium;
A. The paricardial cavity is the space in between the fibrous and
serous layer.
B. Originating from C3 – C5, the nerve that passes through the fibrous
layer of the pericardium give rise to somatic sensation
C. Pericardial cavity in a normal adult contains about 100cc of straw
coloured fluid
D. Most pericardial effusion requires urgent pericardiocentesis
E. In a patient with pericarditis, ECG will always show a saddly-shaped
ST elevation
26. Q & A
• With regards to the pericardium;
A. The paricardial cavity is the space in between the fibrous and serous
layer. F
B. Originating from C3 – C5, the nerve that passes through the fibrous layer
of the pericardium give rise to somatic sensation of the pericardium. T
C. Pericardial cavity in a normal adult contains about 100cc of straw
coloured fluid. F
D. Most pericardial effusion requires urgent pericardiocentesis. F
E. In a patient with pericarditis, ECG will always show a saddly-shaped ST
elevation. F
27. • With regards to the heart chambers:-
A. The coronary sulcus separates the atria from the ventricles.
B. The great cardiac vein run through the coronary sulcus.
C. The fossa ovalis is an embryological remnant of a foramen that
allowed a left to right shunting of oxygenated blood in the fetal
heart.
D. The left ventricle only has 2 papillary muscles preventing eversion
of the valve cusps during contraction.
E. The rapid opening of the AV valve is what gives rise to the 1st heart
sound.
28. • With regards to the heart chambers:-
A. The coronary sulcus separates the atria from the ventricles. T
B. The great cardiac vein run through the coronary sulcus. F
C. The fossa ovalis is an embryological remnant of a foramen that
allowed a left to right shunting of oxygenated blood in the fetal
heart. F
D. The left ventricle only has 2 papillary muscles preventing eversion
of the valve cusps during contraction. T
E. The rapid opening of the AV valve is what gives rise to the 1st heart
sound. F
29. • With regards to the coronary circulation:-
A. The SA and AV nodes is supplied by the RCA.
B. Posteriorly, the LCA terminates as the posterior interventricular
artery.
C. Drainage of the coronary circulation is into the coronary sinus and
into the right atrium.
D. An ST elevation in leads ll, lll, and aVF is due to a block in the branch
from the LCA.
30. • With regards to the coronary circulation:-
A. The SA and AV nodes is supplied by the RCA. T
B. Posteriorly, the LCA terminates as the posterior interventricular
artery. F
C. Drainage of the coronary circulation is into the coronary sinus and
into the right atrium. T
D. An ST elevation in leads ll, lll, and aVF is due to a block in the branch
from the LCA. F
