Week 4 Flashcards
What does the coronary venous blood drain into?
The coronary sinus into the right atrium
What are some of the special features of the coronary circulation?
High basal blood flow
High capillary density
High oxygen extraction
What is the only way to increase perfusion of the heart?
Increasing oxygen flow to the heart y increasing blood flow due to the extraction of o2 from haemoglobin already being max
What changes in gas and metabolic contents cause vasodilation of the coronary arteries?
If Po2 decreases
Adenosine from ATP degradation
Why can tachycardia led to poor perfusion of the heart and chest pain?
Due to perfusion of the left coronary arteries occurring during diastole and the tachycardia shortening diastole. Results in poor perfusion. These are perfused during diastole due to the high pressure during systole constricting sudendocardial blood flow
What arteries make the circle of willis
Basilar artery (from vertebral arteries made from the subclavian arteries) and carotid arteries anastamosing
What is the effect on cerebral blood flow to increased MAP?
Vasoconstriction to avoid damage of vessels
What is the effect of A. increased B. Decreased carbon dioxide in cerebral circulation
A. Increased Co2; cerebral vasodilation
B. Decreased co2; cerebral vasocontriction
Describe the physiology behind someone hyperventilating fainting
As they have a decreased Pco2 the cerebral vessels constrict so o2 doesnt flow to the brain causing fainting
A young athlete suddenly dies, histologically the heart had swirled myofibres. What did they have?
Hypertrophic cardiomyopathy
A man presents with multiple myeloma, and has had developed arrhythmias. What type of cardiomyopathy has he developed?
What stain could be used histologically to confirm the diagnosis?
Restrictive cardiomyopathy due to amyloidosis (deposition of paraproteins) reducing compliance
Histologically; congo red stain positive
Women presents with long history of alcohol missuse and is undergoing chemotherapy with doxorubicin. She has breathlessness, fatigue and chest discomfort. Histologically on the heart there is no signs. What is the diagnosis?
Dilated cardiomyopathy
What heart valve can be affected in a person that has had rheumatic fever ?
Mitral valve to be stenosed
What viral infections can cause myocarditis?
Coxsackie A/B
ECHO virus
What are the common causes of endocarditis?
Congenital defects\
Rheumatic fever
Prosthetic valves
What action aggrevates pericarditis?
Posture related
What is the function of statins?
To reduce cholesterol
What are the two revascularisation techniques?
Cardiac cathetrisation
Coronary angioplasty
Describe cardiac catheterisation
Insertion of a catheter (hollow tube) into a chamber or vessel of the heart
Describe coronary angioplasty (PCI)
Using a balloon to stretch open a narrowed of blocked artery with a stent on the outside
What does the internal mammary artery supply? (Internal thoracic artery
Supplies anterior chest wall and breasts
What is cardioplegia
The intentional cessation of cardiac activity for cardiac surgery
A catheter was inserted to inject contrast dye into the vessels of the heart to identify their structure and see if there were any occlusions. What diagnostic test is this called?
Coronary angiography
Define an aneurysm
Dilation of a vessel by more than 50% of normal diameter by all its layers without a breach in the wall
What is the epidemiology of people with aneurysms
Elderly, male, smoker, hypertensive
Symptoms of abdominal aortic aneurysm?
Central chest pain perhaps mimicing renal colic
When ruptures can radiate to the back
Male elderly patient with past history of smoking and hypertension presents with central pain in chest with a pulsatile mass. What investigations do you order?
Suspect AAA
Duplex ultrasound and CT angiogram
What are the 6 P’s of acute limb ischaemia
Pain Pallour Pulseless Perishingly cold Paraesthesia (pins and needle) Paralysis
If you suspect acute limb ischaemia what investigations should you order?
Arterial imaging
CT angiogram
Man presents with lower left leg feeling extremely cold, with lack of function, pulseless and painful; what is your treatment?
Embolectomy
If it was swollen a fasciotomy may be appropriate
What is diabetic neuropapthy?
Nerve damage secondary to diabetes
What types of infectious organisms can cause diabetic foot sepsis?
Staph aureus
E coli
Enterobacteria
Diabetic presents with a swollen foot with black patches, that is tender and ulcerated. The ulcer is pussing and the foot looks angrily red. In the redder tissues there are crepitations. What is the diagnosis?
Diabetic foot sepsis
Lady presents with possible lower limb ischaemia, investigations and potential treatment?
Comparative BP in legs
Duplex ultrasound scanning
MRI
Treamtnet
Aspirin, statins, ace inhibitors, potential surgery or amputations
What are the components of an arterial embolism?
Mostly platelet rich due to high blood flow
What is the components of a venous embolism
Mainly RBCs due to stasis
What is the function of the drugs apixaban and rivaroxaban?
They are Xa inhibitors so prevent clot formation in the coagulation cascade
What are the components in virchows triad?
Hypercoaguable state
Endothelial injury
Circulatory stasis
What is an ischaemic stroke? What is it caused by?
Where a clot blocks blood flow to an area of the brain
Caused by thrombus, embolism and hypoperfusion
What is haemorrhagic stroke? What can it be caused by?
Where bleeding is inside the brain causing an increase in pressure and decreased blood flow to an area
Can be caused by hypertension, aneurysm, trauma
What increases the risk of stroke?
Hypertension, TIA (transient ischemic attack), smoking, hyperlipidaemia, atrial fibrillation, obesity, smoking
What is TIA
Transient ischaemic attack
Brief episode of neurological dysfunction caused by loss of blood flow in the brain, spinal cord or retina without tissue death
If you suspect stroke what investigations would you do
CT brain angiography, MRI with diffusion weight insquence
Blood tests; to investigate cause of thrombosis or embolism so lipids, glucose, thrombophillia, hypertension
Describe treatment of a stroke
If its been less than 4 hours then treat with thrombolysis medication to dissolve the clot e.g streptokinase
If more than this leading to 6 hours use thrombectomy to remove the clot surgically
If clot from the heart use anticoagulation like rivaroxaban, dabigatran, apixaban and edoxaban
What are the common infectious causes of endocariditis?
HACEK
Haemophilus, actinobacillus, cardiobacteria, eikenella, kingella
What is included in virchows triad?
Hypercoaguable stgate
Endothelial injury
Circulatory stasis
Pleuritic cardiac pain is aggrevated by what ?
Breathing deeply, it is a sharp catching pain
What are some examples of Xa inhibitors in the coagulation cascade?
Apixaban and rivaroxaban
