Week 1 Cardiovascular Flashcards
the base surface of the heart refers to what position
posterior
the diaphragmatic surface of the heart refers to what position
inferior
the left and right surfaces of the heart refer to what position
left and right lateral
the anterior surface of the heart refers to what position
anterior
what chambers are founds on the base surface of the heart
left and right atrium
what chambers are found on the diaphragmatic surface of the heart
right and left ventricle
what chambers are found on the left pulmonary surface of the heart
left ventricle
what chambers are found on the right pulmonary surface of the heart
right atrium
what chambers are found on the anterior surface of the heart
right ventrcle,left ventricle, right atrium
list the borders of the heart
right border
left border
inferior border
superior border
what structure(s)/chamber(s) are found in the right border
right atrium
what structure(s)/chamber(s) are found in the left border
left ventricle (majority)
left atrium (minority)
what structure(s)/chamber(s) are found in the inferior border
right ventricle (majority)
left ventricle (minority)
what structure(s)/chamber(s) are found in the superior border
right atrium
left atrium
auricles
Describe the structure of the cardiac skeleton
-dense fibrous CT
-forms four rings around each of the cardiac valves
-forms two fibrous CORONETS around the aortic and pulmonary valves
-forms two fibrous RINGS around the bicuspid and tricuspid valve
list the functions of the cardiac skeleton
anchorage
insulation
attachment
structure
how does the cardiac skeleton provide anchorage
anchors the heart valves and maintains proper alignment
how does the cardiac skeleton provide insulation
electrically insulates the atria from ventricles, assits with coordinated contractions
how does the cardiac skeleton provide attachment
serves as the myocardial attachment point
how does the cardiac skeleton provide structure
maintains structural integrity of the heart during the cardiac cycle
coronary arteries consist of
left and right coronary arteries
left coronary artery bifrucates into
left anterior descending artery and left circumflex artery
right coronary artery branches into
right marginal artery and posterior descending artery
function of left anterior descending artery
supplies:
-anterior 2/3 of interventricular septum
-left ventricle
-right ventricle
function of left circumflex artery
supplies :
-left atrium
-left ventricle
function of the right marginal artery
supplies right ventricle
function of posterior descending artery
supplies:
-left ventricle
-right ventricle
-posterior 1/3 of interventricular septum
whats a dominance pattern
refers to the coronary artery that supplies the posterior descending artery
describe a left dominant pattern
the left cirucmflex artery supplies the posterior descending artery
describe a right dominant pattern
the right coronary artery supplies the posterior descending artery
Outline the right dominant pattern
function of left marginal artery
supplies left ventricle
location of great cardiac vein
runs alongside left anterior descending artery
location of middle cardiac vein
posterior surface of heart
list the structures of venous drainage of the heart
-coronary sinus
-great cardiac vein
-middle cardiac vein
-small cardiac vein
-anterior cardiac vein
function of coronary sinus
receives blood from several major cardiac veins (middle cardiac vein, great cardiac vein and small cardiac vein) and empties it into right atrium
function of great cardiac vein
drains anterior aspects of heart
function of middle cardiac vein
drains posterior regions of ventricles
function of small cardiac vein
drains right atrium and right ventricle
function of anterior cardiac vein
directly drains the right ventricle into the right atrium (bypasses coronary sinus)
location of small cardiac vein
runs along right atrioventricular groove
list the factors that infleunce autonomic regulation of vascular diameter
metabolic
autonomic innervation
endothelium
physical forces
hormonal
describe sympathetic innervation of coronary arteries
-involves prenganglionic fibres from (T1-5)
-involves post ganglionic fibres from cervical ganglia
-targets the SA/AV node, coronary arteries, cardiomyocytes
-positive inotropic effect
describe parasympathetic innervation of coronary arteries
-consists of preganglionic fibres from brainstems vagal nuclei and vagus nerve
-involves post ganglionic fibres from neurons in cardiac plexus
-targets SA/AV node and coronary arteries
-negative inotropic effect
Describe role of endothelium in cardiac physiology
-endothelial cells that line coronary arteries play a role in regulating vascular tone and blood flow
-release factors like NO that induce vasodilation
-releases endothelin that causes vasoconstriction
Function of arteries
carry oxygenated blood away from the heart to various body tissues
Function of veins
return deoxygenated blood from tissues back to the heart
Function of capillaries
tiny,thin walled vessels where oxygen and nutrients are exchanged within tissues
List the basic principles of circulatory function
-blood is pumped from heart into arteries
-arteries branch into smaller vessels and eventually become capillaries in tissues
-capillaries allow for the exhange of oxygen and nutrients and waste products
-deoxygenated blood returns to heart via veins
-the heart pumps blood to lungs for oxygenation (pulmonary circulation) rest is (systemic)
what is pressure gradient in terms of blood vessels
describes the difference in pressure between two ends of a vessel
what is vascular resistance in terms of blood vessels
the impediment to flow through a vessel
whats ohms law
pressure (gradient)= flow x resistance
identify types of blood flow
laminar or turbulent
what is turbulent blood flow
disorderly, flowing crosswise in in a vessel
what is laminar blood flow
flows in streamlines, with each parallel layer remaining the same distance from the vessel wall
identify the impediments to blood flow
physical
directional
velocity
describe physical impediments to blood flow
physical obstruction such as the presence of atherosclerotic plaque /ischaemia
describe directional impediments to blood flow
change in directions such as the vasculature of the aortic arch
describe velocity as an impediment to blood flow
high velocity can derail trails of laminar flood flow, enabling turbulence
list the factors that affect vascular resistance
-organisation of vascular network
-characteristics of blood
-extravascular mechanical forces
-vessel diameter
-vessel length
Describe, using an example how organisation of vascular network can impact vascular resistance
series circuits result in higher overall resistance and greater pressure drops, while parallel circuits allow for lower resistance, more uniform pressure distribution, and variable flow rates.
describe how characteristics of blood can impact vascular resistance
variables in the blood eg, viscosity, protein, cell levels can impact blood flow
describe how extravascular mechanical forces can impact vascular resistance
things such as compression via muscle contraction and pump can impact flow
describe how vessel diameter can impact vascular resistance
vessel diameter is reciprocal to resistance, decreases as resistance increases
describe how vessel length can impact vascular resistance
vessel length is proportional to resistance, increases as resistance increases
what is vascular conductance
measure of the blood flow through a vessel for a given pressure gradient
-reciprocal of resistance
identify the determinants of coronary blood flow
availability to oxygen
blood vessel diameter
CO
SV
BP
what are the 3 characteristics of coronary blood flow
high oxygen demand
high resting oxygen extraction
limited anaerobic capacity
describe high oxygen demand as a feature of coronary blood flow
unlike other components of the body, the heart is in constant need of oxygen
describe high resting oxygen extraction as a feature of coronary blood flow
at rest, the human heart extracts 70-80% of oxygen delivered from coronary blood flow (contrast to 30-40% for normal tissue)
describe limited anaerobic capacity as a feature of coronary blood flow
the heart fails to work effectively without oxygen supply, this maintains aerobic capacity
what is vasomotor tone
refers to the intrinsic level of contraction and relaxation of vascular smooth muscle which maintains the baseline diameter of blood vessels
identify the factors effecting vasomotor tone
sympathetic innervation
parasympathetic innervation
local gas levels
describe how sympathetic innervation impacts vasomotor tone
the sympathetic branch of the ANS releases norepinephrine and stimulates alpha-adrenergic receptors on vascular smooth muscle cells causing vasoconstriction
describe how parasympathetic innervation impacts vasomotor tone
the parasympathetic branch predominantly affects vasodilation in specific areas, such as genitalia and digestive system
describe how local gas levels impacts vasomotor tone
changes in local tissue oxygen levels (hypoxia) can lead to vasodilation, while high levels of carbon dioxide (hypercapnia) can cause vasoconstriction
what is atherosclerosis
a chronic vascular disease characterised by the build up of atherosclerotic plaque in the coronary arteries, hardening and narrowing the arteries, restricting blood flow to the heart muscle
what is coronary heart disease
involves the narrowing or blockage of coronary arteries due to plaque formation, leading to reduced oxygen supply to the heart and potential angina or MI
what is myocardial infarction
occurs when a coronary artery is completely blocked, usually by blood clot, leading to a loss of blood supply or part of the heart muscle and causing tissue damage or necrosis
what is a coronary artery dissection
a tear in the coronary artery wall causing blood to flow between the layers if the artery, leading to reduced blood flow to heart and possible ischaemia
describe initial stage of atherosclerosis
atherosclerosis process is triggered by a certain stimuli, including trauma, HTN, hyperlipidaemia, triggers endothelial injury and inflammation
describe mid stage atherosclerosis
switch from acute to chronic inflammation, dominated by macrophage activity
describe late stage atherosclerosis
vascular inflammation become less important, involves the formation and rupture of atherosclerotic plaques
Outline mechanism of atherosclerosis
-endothelial damage (various causes eg HTN,Smoking,Diabetes)
-dyslipidaemia (high LDL’s/low HDL’s)
-more LDL diffuses across damaged endothelium and accumulates in the intima
-LDL in the intima is oxidised into lipids that trigger chronic inflammation of vessel wall
-inflammation attracts macrophages
-CAM’s allow macrophages to attach to the endothelium
-macrophages enter (via diapedesis) phagocytose the oxidised LDL and become filled with fat (foam cells form)
-foam cells accumulate in intima forming lipid core
-SM cells move towards intima, lay down fibrous CT (collagen) that accumulates around lipid core, forming fibrous cap
-fibrous cap eventually bursts (collagen becomes unstable)
-development of atheroma –>atherosclerosis
-this can attract a thrombus which can lead to an embolus (and block various blood supply to other areas)
identify some sources of endothelial damage
-hypertension
-hyperglycaemia
-free oxygen radicals (from smoking)
-hyperlipidaemia
-physical injury
-turbulent blood flow
what molecules modulate WBC movement during atherosclerosis
selectins
integrins
Cell adhesion molecules (CAMS)
role of selectins in atherosclerosis
monitor monocyte adhesion under flow by capturing monocytes
role of integrins in atherosclerosis
adhesion of monocytes
role of CAM’s in atherosclerosis
bring leukocytes to complete arrest
list two CAM’s
VCAM-1
ICAM-1
what is VCAM-1
vascular protein; binds to VLA-1 and a4B1 integrin, expressed by endothelial and smooth muscle cells
what is ICAM-1
intracellular proteins; binds to LFA-1; expressed by endothelial cells and leukocytes
what are fatty streaks
early precursor lesion of atherosclerosis (lacks fibrosis, thrombosis or calcification)
list the histopathological features of atherosclerosis
neovessel formation
apoptotic macrophages
plaque crystals
describe neovessel formation (atherosclerosis)
aims to supply oxygen and nutrients to hypoxic regions of the plaque, the resulting new blood vessels are often fragile and contribute to plaque instability and the risk of rupture
describe apoptotic macrophages (atherosclerosis)
the failure to efficiently clear apoptotic macrophages within atherosclerotic plaques leads to secondary necrosis, inflammation, and plaque instability.
describe plaque crystals (atherosclerosis)
crystallisation due to the formation of plaques within blood vessels
name some cells involved in atherosclerosis
monocytes/macrophages
platelets
T cells
SMC’s
Dc
neutrophils
describe interplay between macrophages and SMC’s
-as plaques develop, SMC’s migrate towards plaque surface, secrete collagen and form a fibrous cap
-SMC’s also contribute to plaque expansion by releasing inflammatory chemokines
-this causes recruitment of monocytes and macrophages
-SMC apoptosis occurs, exacerbating plaque inflammation and instability
what is the prevalence of hypertension in men globally
32-37%
what is the prevalence of hypertension in women globally
30-34%
describe the difference between primary and secondary hypertension
-primary hypertension describes high BP with no identifiable underlying cause and is thought to be a combination of genetic, environmental and lifestyle factors
-secondary hypertension arises from. an identifiable underlying condition
identify the causes of secondary hypertension
metabolic syndromes
adrenal (phaechromocytoma)
medication/drugs
renal disease
hyper/hypothyroidism
polycystic ovary syndrome
address the treatment of primary vs secondary hypertension
primary=requires long term management through lifestyle modifications and pharmacotherapy
secondary=treating the underlying contributing condition
outline the pathophysiology of secondary hypertension (RENAL)
-damaged kidneys have a lesser capacity to excrete sodium and water, leading to fluid retention and increased BV
-this causes dysregulation of RAAS
-elevated levels of angiotensin II and aldosterone, leading to vasoconstriction
outline the pathophysiology of secondary hypertension (thyroid)
-in hyperthyroidism, elevated thyroid hormones increase CO and enhance peripheral vascular resistance leading to increased BP
-in hypothyroidism, reduced thyroid hormones can lead to increased peripheral resistance and dyslipidaemia, leading to increased BP
signs and symptoms of primary hypertension
-generally asymptomatic
-in extreme cases–> headache, epistaxis, arrhythmias, visual disturbances, chest pain, dyspnoea, confusion
signs and symptoms of secondary hypertension
-can present alongside end organ damage, leading to CAD, stroke, renal disease, retinopathy
-heart palpitations (due to phaechromocytoma) and anxiety
list the investigation methods for hypertension
EUC, ACR
TFTs
Lipid profiles
Urinanalysis
Describe the use of EUC and ACR for hypertension investigation
increased creatinine, abnormal albumin-creatinine ratio, or low GFR may indicate hypertension due to renal impairment
ACR and EUC stand for
albumin creatinine ratio
Electrolytes, urea, creatinine
Describe the use TFTs for hypertension investigation
thyroid function tests, abnormal thyroid hormone levels may indicate hypertension due to hypo/hyperthyroidism
Describe the use lipid profiles for hypertension investigation
tests for hyperlipidaemia, when found alongside hypertension, this poses pt at severe cardiovascular risk
Describe the use urinalysis for hypertension investigation
detects proteinuria or other abnormalities indicating potential kidney involvement in hypertension
values for different degrees of HTN
normal 120-129 and 80-84
elevated normal: 130-139 and 85-89
grade 1: 140-159 and 90-99
grade 2: 160-179 and 100-109
grade 3 180+ and 110+
list the stages of severe hypertension
-severely elevated hypertension without symptoms
-hypertensive urgency
hypertensive emergency
features of severely elevated hypertension without symptoms
-180/110 or higher
-no symptoms or end organ damage
-no immediate threat to life
-treatment within 1-2 days
features of hypertensive urgency
-180/110 or higher
-symptoms present
-no end organ damage
-moderate non acute damage/dysfunction
-treatment within hours
features of hypertensive emergency
-220/140 or higher
-symptoms present
-significant acute end organ damage
-immediate threat to life
-treatment within minutes
effects of hypertension on brain
stroke; initiates thrombus formation leading to reduced cerebral perfusion
effects of hypertension on heart
MI, left ventricular hypertrophy, CHF
effects of hypertension on kidneys
-exacerbate/cause renal failure due to pressure imbalances in nephron
effects of hypertension on eyes
hypertensive retinopathy; causing damage to retina and changes such as retinal haemorrhages and exudates that can impair vision
effects of hypertension on blood vessels
-atherosclerosis, that can form a clot which lodges in areas such as heart, brain or lungs (embolism)
-can cause PVD and infarctions
identify the ways we can image the chest
chest radiograph
CT chest
MRI chest
ultrasound
digital subtraction angiography
benefits of x ray imaging
-good for looking at bones
-good for distinguishing between air filled structures and soft tissue
limitations of x ray imaging
-cant distinguish between adjacent tissues of the same density
what view is the standard X-ray
PA, posteroanterior
what are the lab conditions for a chest x ray
-taken at 6 feet
-upright on full inspiration
-patient close to the film
features of AP film
-used on adult patients (sick) or children
-may be supine or sitting
-taken at shorter distance from film
why are lordotic view x rays used
to further assess apical pathology that may be obscured on a frontal film
why are lateral decubitus view x rays used
-look for air trapping in lungs
-check for pleural air (rises) or pleural fluid (layers dependently)
why are expiratory films used
-pneumothorax (more obvious on expiration)
-detect focal air trapping (the obstructed lung will appear darker)
outline the systematic approach to interpret an x ray
INSIDE OUT
-heart
-mediastinum
-hilar
-lungs
-pleural reflections
-upper abdomen
-bones
-soft tissues
how do CT scans work
2D images are acquired in the axial plane but can be reconstructed in multiple 2D planes and in 3D
what is the purpose of CT
achieve greater contrast resolution (allow for differentiation between different soft tissues)
define hounsfield units
standardised unit, relative to water, reflecting attenuation or density
hounsfield units for air, fat, water, organs, bone and metal
air=-1000
fat=-120 to -90
water=0
organs=20 to 60
bone = 2000
metal= 3000
list the different types of CT
Standard CT chest (post contrast)
High resolution CT (non contrast)
CT aortogram (+/- gating)
CT Pulmonary angiogram
CT Coronary angiogram
What conditions are standard CT chest used for
pneumonia, malignancy, pleural disease
What conditions are high resolution CT used for
parenchymal diseases, eg interstitial lung disease
What conditions are CT aortogram used for
aortic pathologies
What conditions are CT pulmonary angiogram used for
pulmonary embolism
What conditions are CT angiogram used for
coronary artery disease
features of standard CT chest
-post contrast
-triggered at approximately 20seconds when the contrast is in the arterial system
features of high resolution CT
-non contrast
-thin slices
-post processing
-can be done on expiration
-can be performed prone
features of CT aortogram
-more rapid injection of contrast
-can be gated (scan is triggered at a particular point of CC -via ECG monitoring)
-usually mid to end diastolic
features of CT pulmonary angiogram
-contrast injected at a raid rate
-timed for peak contrast enhancement (triggered in region of interest)
-apices to diaphragm only (view)
features of CT coronary angiogram
-uses high contrast flow rate
-timed for peak opacification of coronary arteries
-medications sometimes used in conjunction (ie to lower HR)
-ECG gated
-post processing (curved reconstructions, MPR, MIP)
what do MPR and MIP stand for
MIP = maximum intensity projection MPR = multiplanar reconstruction
what is a lordotic view
the clavicles appear high such that the lung apices are not visible above the clavicles. The ribs appear more horizontal and are more V-shaped than C-shaped
what is a lateral decubitus view
pleural and peritoneal cavities are visible
how does pheochromocytoma cause HTN
-excess release of catecholamines
-causing vasoconstriction
-increased CO and paroxysmal HTN
how does cushings syndrome cause HTN
-excess cortisol release
-increased sodium and potassium retention
-increased BP
