Anatomy and pattern recognition of the cardiovascular system Flashcards
What are the functions of the cardiovascular system?
Deliver nutrients and oxygen to tissues
• Remove waste products of cellular metabolism (e.g. CO2)
• Transport hormones and drugs
• Acid base balance
• Blood clotting (haemostasis)
• Distribution of heat
• Immune response
How does blood flow through the body
Deoxygenated blood flows from the vena cava into the right atrium,then passes through tricuspid valve into the right ventricle, it then passes through the pulmonary valve into the pulmonary artery and then to the lungs to be reoxygenated. oxygenated blood travels from the lungs through the pulmonary veins into the left atrium then the mitral valve, then the left ventricle, then the aortic valve, and finally the aorta from where oxygenated blood is sent out to the rest of the body.
Blood vessel structure - 3 layers
Tunica intima (endothelium) = inner part of the vessel provides friction of surface
Tunica media (smooth muscle and elastic tissue) = composed of elastic and muscular tissue which regulates the internal diameter of the vessel
Tunica Adventitia (fibrous tissue) = outer layer which provides structural support and shape to the vessel
Aorta
- Oxygenated blood from the heart is distributed from the aorta to all parts of the body
- It is divided into the ascending aorta, aortic arch and descending aorta
- We also divide it medically into the thoracic and abdominal aorta – at the level of the diaphragm
- It stretches to receive ejected blood from the left ventricle
- It has a large diameter, is relatively thin walled and
highly elastic
Thoracic aorta - above your diaphragm
- Is the main blood vessel in the thoracic cavity
- Originates from the left ventricle
- Transmits oxygenated blood to organs within the thoracic cavity, head, neck and upper limbs.
- Comprises of the:
Ascending aorta
Arch of the aorta
Descending aorta
Ascending aorta
Approximately 5cm in length
• Begins at the aortic valve and ends at the level of the sternal angle where it becomes the aortic arch
• Contains 3 aortic sinuses, 2 of which become the right and left coronary arteries.
Right coronary artery
• Supplies both ventricles and right atrium
Left coronary artery
• Supplies both ventricles and the left atrium
Coronary arteries
The coronary arteries encircle the heart
• There is a left and right coronary artery which supply oxygenated blood to the myocardium
• The myocardium receives blood from branches of more than 1 artery and when 2 or more arteries supply the same region they usually connect. These connection are called anastomoses.
• The provide alternative routes called collateral circulation for blood to reach an organ.
• The coronary arteries have many anastomoses to provide detours for arterial blood if a main route becomes obstructed. This is important – the myocardium will still receive sufficient oxygen even if 1 of the coronary arteries is blocked.
Aortic arch
• 4-5cm long and is the continuation of the ascending aorta
• Three major branches
The brachiocephalic trunk – subdivides to form the right subclavian and right common carotid arteries
Left common carotid
Left subclavian
Thoracic / descending aorta
Approximately 20cm long, continuation of the aortic arch
Branches are:
• Bronchial – bronchial tree and alveolar ducts
• Posterior intercostal – skin, muscle and ribs of thoracic wall. Thoracic vertebra and spinal cord
• Subcostal – skin muscles and ribs, T12
• Mediastinal – mainly lymph nodes and
connective tissue in the mediastinum
• Oesophageal – oesophagus
• Pericardial – pericardial sac
• Superior phrenic artery – diaphragm and pleura
Abdominal aorta
Main vessel in the abdominal cavity
• Transmits oxygenated blood from the thoracic cavity to organs within the abdomen and lower limbs
• It is a continuation of the thoracic aorta
• Descends in the retroperitoneum anteriorly and slightly to the left of the lumbar vertebral bodies
• The inferior vena cava lies to its right
• It terminates at L4 into the right and left common iliac arteries and the median sacral artery
Arteries - break off from the aorta
Carry blood away from the heart to other organs
There are 2 main types
Muscular arteries = control the rate of blood
● The tunica media contains more muscle and fewer elastic fibres
● These arteries can vasodilate and constrict to adjust the rate of blood flow and deliver blood to the organs
Elastic arteries = propel blood
- The largest in the body with a thick tunica media
- Includes the aorta, pulmonary trunk and aorta.
- They propel blood onward while the ventricles are relaxing
Arterioles
Means ‘small arteries’
• They regulate the flow of blood into the
capillary networks of the body’s tissues
• A change in arteriole diameter can affect the blood pressure
• Vasoconstriction – increases blood pressure • - - -Vasodilation – decreases blood pressure
Veins
Veins have thin wall compared to the arterial wall
• Walls are formed from the same 3 layers as arteries, but the thickness of the layers is different.
• Veins can distend enough to cope with variations in blood flow but cannot withstand high pressure
• Veins have valves with valve cusps which point towards the heart. This prevents backflow of blood
Inside heart chambers
Endocardium = inner most layer of the hearts walls a thin, smooth tissue that makes up the lining of the chambers and valves of the heart
Myocardium = cardiac muscles responsible for the pumping of the heart
Pericardium = outer layer which protects the heart and produces fluid
Surface landmarks heart
Superior border
● 2nd left costal cartilage and 3rd right costal cartilage
o Right border
● 3rd right costal cartilage and 6th right costal cartilage
o Inferior border
● 6th right costal cartilage and the 5th left intercostal space in the midline
o Left border
● 2nd left costal cartilage and the 5th left intercostal space in the midline.
Atherosclerosis
• Calcified plaques in the intima of large and medium sized arteries
• They begin as fatty streaks, some of which progress to plaques
• Plaques can progressively enlarge causing stenosis and ischemia
• They can rupture causing a thrombus formation, total occlusion and critical ischemia
• Can put pressure on the underlying media causing an aneurysm
• Risk factors
o Increasing age
o Hypertension
o Smoking
o Diabetes
o Family history
o Alcohol
o Obesity
o Conditions it can cause include
- Ischemia / infarction – MI, angina, cardiac failure, TIA, stroke, peripheral vascular disease
- Aneurysmal dilation- thoracic or abdominal aortic aneurysm
Heart failure diagnosis
- Blood tests to check for damage
o ECG and / or echocardiogram
o Spirometry
o CXR - only about 70% accuracy. But may see pulmonary venous congestion, cardiomegaly,
pulmonary oedema, pleural effusions.
o US is the most common imaging used – transthoracic echocardiography. It can assess the
appearance and function of the ventricles, assess the valve anatomy and function and look at
the pericardial space
o Cardiac CT can provide estimates of cardiac function and visualisation of cardiac structures
o Cardiac MRI can provide highly accurate ejection fractions, identify abnormalities and is considered the gold standard imaging modality.
Heart failure complications
o Prognosis is poor – up to 70% of patients die within 5 years.
o Acute pulmonary oedema
o Arrhythmias such as ventricular tachycardia (can lead to VF and death)
Heart failure treatments
o Make healthy lifestyle changes
o surgical management
- Implantable ICD or PPM, cardiac transplant
o Treatment of complications
o Medication – betablockers most commonly
What is pericardial effusion
Occurs when excess fluid collects in the pericardial space (normally 30-50ml)
What are causes and symptoms of pericardial effusion
Lots of causes Including pericarditis (inflammation of the pericardium due to injury or disease), MI, RA, metastasis, particularly lung and breast.
Symptoms
• Symptoms can include dyspnoea, reduced exercise tolerance.
Diagnosis of pericardial effusion
• CXR – need at least 200ml of fluid to see on a CXR. But may see heart enlargement (looks like a water bottle), pulmonary oedema
• Echo – method of choice as you can measure the amount of fluid and assess the impact on cardiac function
• CT/ MRI – pericardium thickness of more than 4mm is considered abnormal
Complications and treatment of pericardial effusion
Complications = can lead to cardiac tamponade and death
Treatment = • Small amount of fluid is usually managed conservatively
• Large amount – can be drained
What is Mitral valve regurgitation
Condition where the mitral valve leaks during systole (pumps blood into arteries) and so blood flows in the wrong direction from the left ventricle into the left atrium
Causes and symptoms of Mitral valve regurgitation
• Chronic - Increasing age, congenital heart defects, calcium buildup preventing the valve from correctly functioning, cardiomyopathy
• Acute – MI, trauma
Symptoms
• Acute – severe symptoms of heart failure, shock
• Chronic – heart murmur on examination, dyspnoea, arrhythmia or palpitations
Diagnosis of Mitral valve regurgitation
• CXR – signs of left atrial enlargement (splaying of the carina, loss of the left atrial appendage), features of heart failure, pulmonary oedema
• Echo – useful for assessing the cause and reviewing the left ventricle
• CT / MRI – not commonly used but may have some uses in assessing the underlying cause
Complications and treatment of Mitral valve regurgitation
Complications
• Heart failure, pulmonary hypertension, AF, sudden cardiac death.
Treatment
• Acute – mitral valve replacement
• Chronic – Drugs such as ACE inhibitors, anticoagulation.
Coronary-artery disease
Description
o This mainly refers to the narrowing of the coronary arteries due to atherosclerosis (calcification). This results in myocardial ischaemia and globally is the leading cause of death
• Causes
o Atherosclerosis
• Symptoms
o May be asymptomatic but include chest pain and angina symptoms
• Diagnosis
o Coronary angiography and CTCA both look for luminal narrowing
• Complications
o MI due to complete artery occlusion
o Heart failure
• Treatment
o Drugs to vasodilate and reduce blood pressure.
o Stents
o Coronary artery bypass grafts
Coronary artery bypass graft (CABG)
- Surgical procedure to increase blood flow to the myocardium due to coronary artery stenosis
- Both arteries and veins can be grafted, often from the patient’s leg or arm.
- Often grafted onto the left internal thoracic artery.
- Post CABG patients can develop
• Pleural or pericardial effusions
• PE
• Infection
Atrial fibrillation
Description
• Is a supraventricular tachycardia with uncoordinated atrial electrical activation, and ineffectual atrial contraction leading to an irregular and often abnormally rapid ventricular rhythm – an arrhythmia)
Causes
• Hypertension, ischaemic heart disease, heart failure, valvular heart disease, lifestyle
Symptoms
• Often asymptomatic
• May have an irregular pulse, dyspnoea, chest pain, dizziness, syncope (fainting).
Diagnosis
• ECG, identifying the underlying cause.
Complications
• Stroke, heart failure, increased all cause mortality.
Treatment
• Anticoagulation for stroke prevention, drug treatments for rate control, cardioversion, PPM
Abdominal aortic aneurysm
Description
• Also called a AAA
• Focal dilatation of the abdominal aorta > 3cm in diameter
Causes
• Increasing age, males more affected.
Symptoms
• Most are asymptomatic until they rupture so often an incidental finding.
• Patients may have pain or a pulsatile mass
Diagnosis
• AXR Curvilinear calcification.
. CT Gold standard for evaluation, but high radiation dose
. US Best for screening and surveillance due to speed and no radiation dose Sensitivity and specificity of nearly 100%
. EVAR Endovascular aneurysm repair
Complications
• Rupture – 70% mortality before surgery
Treatment
• Generally, surveillance for less than 5cm and surgery for >5cm.
• May have an EVAR procedure
Atherosclerosis in the lower limbs / peripheral arterial disease
Description
• Plaques causing stenosis in the arteries of the legs.
Causes
• Risk factors include
• Diabetes, smoking, advancing age, hypertension, obesity
Symptoms
• Leg pain when walking, cramping in the thigh or calf, weakness or pins and needles in the lower legs or feet, coldness in the feet, weak pulse in the feet
Diagnosis
• On plain film you may see atherosclerotic plaques in the vessels
• US – can evaluate the arterial wall. US will see calcification as hyperechoic foci and when large, acoustic shadowing.
• CTA – uses contrast to look for luminal narrowing
Complications
• Severe pain, critical limb ischaemia, death of tissue due to infection, amputation due to gangrene
Treatment
• Lifestyle changes
• Angioplasty or bypass graft
Stroke - Ischaemic
Description
• Artheroschlerotic, tumour, thrombus, hupertension
Causes
• Paralysis or numbness of face, confusion and difficulty speaking, headache, vision problems, unilateral weakness
Diagnosis
• Can haemorrhage, can have complications such as aspiration pneumonia and PE. Seizures,
Complications
• Need to have fast treatment to encourage reperfusion
• Thrombolysis, clot retrieval
Stroke – ischemic - CT symptoms
o Earliest CT sign is a hyperdense vessel sign –
representing the clot
o As time progresses and changes become chronic
you will see low density.
Stroke – ischemic - MRI
• More time consuming but has a higher sensitivity and specificity for diagnosing ischemic infarction in the initial stages
Stroke - hemorrhagic
Description
• Can be spontaneous or can be from an ischemic stroke, a vascular malformation, a tumour or metasteses
Causes
• Similar to those of an ischemic stroke. Patient is more likely to have decreased consciousness. May also have headache, nausea and vomiting and seizures
Diagnosis
• Seizures, swelling of the brain, memory loss, vision and hearing problems, death
Complications
• Management is time critical.
• Blood pressure needs to be controlled, management of any raised intercranial pressure (drain), surgery to evacuate the blood, management of seizures - intubation
Stroke – hemorrhagic - CT
• Usually, the first modality used
• Imaging findings
• Hyperdense blood, often with surrounding
edema
• May also see midline shift, hydrocephalus
(increase in CSF and enlarged ventricles)
Stroke – hemorrhagic - MRI
• Findings depend on the size and age of the blood
• Can also show causes – small vessels1
Subarachnoid hemorrhage
• Also called a SAH
• Description
o Is a type of intracranial haemorrhage with
blood in the subarachnoid space
• Causes
o There are 2 causes
- Trauma
- Spontaneous – which can be due to a ruptured
aneurysm, various malformations (AVM, SAM),
anticoagulation therapy
o Risk factors include:
o Patients tend to be older middle age, often
less than 60
o Family history
o Hypertension
o Heavy alcohol consumption
o Abnormal connective tissue
Subarachnoid haemorrhage symptoms and treatment
• Symptoms
o Thunderclap headache
o Collapse and loss of consciousness
• Treatment
o Varies depending on the underlying cause
Subarachnoid hemorrhage - CT
• CT normally performed first due to availability
• Will see hyperdense material in the subarachnoid space – most commonly around the circle of Willis
Subarachnoid hemorrhage - MRI
• MRI is more sensitive than CT at both identifying haemorrhage and diagnosing the underlying cause
• BUT – poor availability, longer scan, greater difficulty with unstable and ventilated patients
• Will see blood as a hyper intensity in the subarachnoid space on FLAIR
PICC lines
• Peripherally inserted central catheters
• Mainly used in oncology patients and chronic diseases e.g. cystic fibrosis
• Can have long term central venous access without a tunneled port
• Performed under local anesthetic.
• Normally accessed through the brachial veins
• Often done in theatre or in fluoroscopy
Vascath
• Generally used for dialysis
• Larger diameter than most CVC’s
Hickman catheter
• Tunneled line
• Typically inserted into the jugular vein and the proximal tubing is tunneled through the subcutaneous tissue to a skin incision on the chest.
• Used commonly for chemotherapy drugs, parenteral nutrition and long- term antibiotics
Port-a-cath (implantable port)
• Used for patients requiring long term
venous access
• They can last for years (PICC last for weeks
or months)
• They require less upkeep (PICC require daily
flushing)
• They are waterproof
• Useful for patients who
- Need long term IV medicine – commonly chemotherapy or antibiotics
- Peripheral access where cannulation is difficult
- To withdraw blood on a regular basis
Pacemaker
• Inserted to improve patient outcome by cardiac pacing.
• This includes
o stimulating a faster heart rate when the heart is beating too slowly (Bradycardia causing syncope)
o Maintaining a suitable heart rate and rhythm – e.g. patients in AF
o In patients with heart block – pulse sent from SA node to AV is delayed or absent
o It can reduce symptoms of heart failure such as breathing problems and lower limb oedema.
o It can prevent syncope
o Most pacemakers are demand pacemakers so only pace on demand
Appearances on a CXR
• Duel lead
o Atrial lead in the right atrial appendage usually pointing cranially
o Right ventricular lead is in the RV apex pointing up towards the upper heart border
o On a lateral image both leads should point anteriorly
Appearances on a CXR
• Single lead
• Lead sits within the right atrium or the right ventricle depending on the clinical presentation
AICD / ICD’s
• Automatic implantable cardioverter defibrillators
• Device recognises ventricular tachycardia and fibrillation and terminates it by delivering an electrical shock
• They are generally implanted in patients with cardiomyopathy who are at risk of VT,VF and sudden cardiac death
• The thicker bit at the end of the lead is the shock coil
• Also useful in patient monitoring of VF and VT.
• You will often find both an ICD and a PPM used to treat the arrthymia and act as a fail safe system.
Implantable loop recorder
• Small device that sits under the skin for cardiac monitoring
• Continuously performs ECG’s and stores any arrhythmias for review.
• Can be activated by abnormal heart rhythm or by the patient manually
Sternotomy wires
• Sternotomy wires are stainless steel wires used to hold the sternum together after heart surgery and a median sternotomy
• Needed to maintain the stability of the sternum during respiration
• Can be single wires or a figure of 8 layout
Heart valve replacement
• All 4 heart valves can be surgically replaced.
• Most common are the aortic and mitral valves
• They are sometimes replaced via a catheter from a
femoral artery approach called a TAVI
