Cardiology Flashcards
How is an MI defined?
Rise and/or fall in troponin with at least one value greater than the 99th percentile of the the upper limit + cardiac chest pain OR ECG changes (new ST segment change or new LBBB)
How is the of occlusion in an NSTEMI?
At least 70 percent of the luminal space
If over 70 percent of the intraluminal space of the coronary artery is occluded what symptoms will result?
Unstable angina or non st elevation MI
Which type of MI has less of the lumen included?
STEMI
What is a type 1 MI and how does it happen?
Spontaneous MI due to plaque rupture
What is a type 2 MI and how does it happen?
Ischaemic imbalance due to coronary spasm, embolism, dissection, hypotension etc
What is a type 3 MI and how does it happen?
Cardiac death to due presumed MI
What is a type 4a MI and how does it happen?
Related to PCI and shows > 5 times upper limit for troponin
How does a type 4b MI occur and how is it confirmed?
Stent thrombosis and confirmed by angiography or autopsy
What is type 5 MI and what is key diagnostic factor?
Related to CABG and over 10 times upper limit for troponin
What percentage of those that die due to acute myocardial infarction die before they reach hospital?
33 percent
What anatomical factors can determine infarct size?
Distribution of occluded artery
Proximity of coronary occlusion
Collateralised blood supply of site of occluded artery
What is the first line treatment in a patient complaining of chest pain in A and E?
ECG followed by clinical assessment
After ECG and clinical assessment what investigation should be done?
Bio markers such as troponin
What is the emergency treatment for STEMI?
Primary PCI Aspirin plus ticagrelor GP IIb/IIIa inhibitor Unfractionated or low molecular weight heparin PPCI
Give examples of P2Y12 receptor antagonists?
Clopidogrel - slow
Prasugrel - fast
Ticagrelor - fast
Which P2Y12 receptor antagonists are given as pro drugs?
Clopidogrel and prasugrel
Which P2Y12 have the greatest anti platelet activities?
Prasugrel
Ticagrelor
Does a STEMI or NSTEMI give you a greater probability of dying?
NSTEMI
What is the immediate treatment in suspected NSTEMI?
Aspirin 300mg, fondaparinux/ UFH, ticagrelor 300mg
+- tirofiban/eptifibatide for intermediate or high risk groups
In low risk NSTEMI what is the second line treatment?
Conservative management
How is a low risk NSTEMI defined?
Less than 3 percent
How is an intermediate NSTEMI defined?
Between 3 and 6 percent
How is a high risk NSTEMI defined?
Greater than 6 percent risk
What is the second line treatment in intermediate or high risk STEMI?
Coronary angiography within 96 hours and then decide PCI or CABG
What are the complications following MI?
Heart failure
Bradyarrhythmias
Tacharrhythmias
What type of Post MI bradyarrhymias may occur?
Intermittent AVN block (Mobitz I)
Complete AVN block
How are Mobitz I heart block and complete AVN block treated post MI?
Atropine if rate is slow
Pacing rarely needed
Usually spontaneous recovery after 7 days with a good prognosis
How is heart failure post MI treated?
IV furosemide - give haemofiltration if diuretic resistant
RAAS inhibition either by ACEI/ARB and then give eplerenone
Ionotropes - noradrenaline and dobutamine
If needed give LV support device such as balloon pump or LVAD
How is intermittent block of both bundle branches (Mobitz II) or complete block of both bundle branches post MI treated?
Pacing needed
No spontaneous recovery with a poor prognosis
How is post MI AF treated?
Rate control via beta blocker
DC cardio version if haemodynamically compromised
+- cardio version
How is VT or VF post MI treated?
DC shock
When do VT or VF after MI occur?
In the first 24 hours - little effect on prognosis
How can late presenting VT/VF post MI complicate things?
Poor prognostic sign and predictive of sudden cardiac death within a year
How many people die from VF post MI pre hospital?
33 percent
How is VF pre hospital treated?
Defibrillator as soon as possible
What complication can a large MI cause?
Left ventricular failure - initiate reperfusion therapy ASAP
What two things usually cause late death post MI?
Recurrent ischaemic deaths - need to implement secondary prevention
Lethal arrhythmia- may need implantable defibrillator
What are the pharmacological agents for secondary prevention of MI?
Aspirin Station Beta blocker ACE I P2Y12 receptor antagonist (not given for life)
In what age groups in heart failure most diagnosed in?
Over 65s
What can cause systolic dysfunction of the heart muscle?
Ischaemic heart disease
Pressure or volume overload such as in AS or hypertension
Cardiomyopathy
What does diastolic dysfunction mean?
Inability of the heart muscle to relax and refill?
What can cause diastolic dysfunction of the heart muscle?
Amyloid
Myocardial fibrosis
Constrictive pericarditis
What are the compensatory mechanisms the heart has to deal with heart failure.
Frank Starling - increased stretching leads to increased contraction
Hypertrophy with possible chamber dilatation
Activation of noradrenaline, RAAS, ANP
What type of hypertrophy does pressure overload lead to?
Concentric hypertrophy
Which type of heart remodelling does volume overload lead to?
Cavitary dilation that may be without thickening
How does hypertrophy affect the perfusion of the heart muscle?
Decreased capillaries leading to an increase in fibrotic tissue but there are already increased metabolic needs leading to worsening HF
How does pulmonary congestion and oedema occur in left sided heart failure?
Decreased peripheral pressure and damming of blood in pulmonary circulation causes the lungs to be congested, oedema to develop and accumulation of haemosiderin laden macrophages. These lead to dyspnoea, orthopnoea and PND
What is right sided heart failure usually secondary to?
Left ventricular failure
Which complications can arise from right sided heart failure?
Pulmonary hypertension that can cause the liver to become congested creating nutmeg liver. Portal vein pressure will also increase leading to splenomegaly and ascites.
What is nutmeg liver and how does it occur?
Blood backing up in the liver due to right sided heart failure causing pulmonary hypertension. This leads to centrilobular necrosis and fibrosis.
How is hypertension defined?
Diastolic > 90 or systolic > 140
What percentage of hypertension is primary?
95 percent
What percentage of hypertension is malignant?
5 percent
How is blood pressure worked out?
BP=COxPeriperal Resistance
What can affect cardiac output?
Blood volume
Heart rate
Contractility
What can alter blood volume?
Sodium
Mineralocorticoids
Atriopeptin
What can increase peripheral resistance?
Constrictors e.g. Angiotensin II, catecholamines, thromboxane, leukotrienes, endothelin
Dilators e.g. Prostaglandins, kinins, NO
Local factors e.g. Autoregulation, pH, hypoxia
Neural factors, constrictors are alpha adrenergic and dilatory are beta adrenergic
What genetic influences may raise blood pressure?
Defects in renal homeostasis Functional vasoconstriction (may lead to increased vascular reactivity) Defects in vascular smooth muscle growth and structure
How does hypertension affect small vessels?
Hyaline ateriosclerosis (especially kidneys)
Hyper plastic ateriosclerosis (onion skinning)
Fibrinoid necrosis in accelerated disease
What is cor pulmonale?
Right ventricular hypertrophy with right atrial hypertrophy and dilation
What are clinical features of cor pulmonale?
Thickened right ventricle (normally greater than 0.5cm)
Possibly tricuspid regurgitation
Acute or chronic
What is vasculitis?
Inflammation of the vessel walls
Can vasculitis be caused by infection?
Yes
How is non infectious vasculitis mediated?
By immune complexes such as ANCA mediated, direct antibody mediated, cell mediated, paraneoplastic or idiopathic
What is common to all forms of vasculitis?
Vessel injury with mural necrosis and haemorrhage
How can vasculitis be classified?
On pathogenesis Vessel size Localised, systemic or organ restricted Can be granulomatous Secondary ischaemia of downstream tissue
What is the clinical picture of polyarteritis nordosa?
Systemic vasculitis
Small and medium sized arteries affected
Often spares lungs
Segmental necrosing inflammation of the GI tract/renal/cardiac arteries especially
Branching sites
Leads to aneurysms, infarcts and haemorrhage
Fibrinosis becomes nodular later on in the disease
Lesions of different ages
What is seen on histology with polyarteritis nodosa?
Transmural inflammation and fibrinoid necrosis
What is found in 30 percent of polyarteritis nodosa cases?
Hep B antigen positive
What further clues may point to a diagnosis of polyarteritis nodosa?
Young adults Acute/subacute/chronic Episodic Gangrene Vague aches and pains Infarcts Hep b or c No haematuria No glomerular involvement
How is polyarteritis nodosa treated?
Steroids and cyclophosphamide
What are the features of ANCA related vasculitis?
Systemic/renal limited/other
85 percent of cases ANCA positive
Flu like illness
Fever, athralgia, myalgia, purpura, peripheral neuropathy, GI involvement
Possibly provoked by drugs - propylthyrouracil, penicillamine, hydrasalazine)
Which drugs can trigger ANCA associated vasculitis?
Propylthyrouracil, penicillamine, hydrasalazine
What are the features of Wegeners granulomatous?
Upper and lower respiratory tract
Ocular/ ear involvement
Necrotising granulomas
Vasculitis
Which antibody is present in Wegners granulomatosis?
cANCA usually against proteinase 3 (PR3)
What are clinical signs and symptoms of Wegeners granulomatosis?
Sore joints Destruction of the face Trace of blood in the urine Gangrene Permanent kidney failure Sore eyes and ears Lung cavities and bleeds
Which test is positive in Wegeners granulomatosis?
Positive anti neutrophil cytoplasm test (cANCA)
How is Wegeners granulomatosis treated?
Aggressive immunosuppression with cyclophosphamide and steroids.
What is cardiomyopathy?
Cardiac disease resulting from a primary intrinsic myocardial abnormality - other causes, such as ischaemia, need to be excluded
What types of cardiomyopathy are there?
Idiopathic or secondary to a known cause
Dilated - ventricles enlarge
Hypertrophic - ventricles thicken and become stiff
Restrictive - walls of the ventricle become stiff but do not thicken
What are features of dilated cardiomyopathy?
Progressive cardiac dilatation and contractile dysfunction
Large heart with four chamber dilation
Valves are arteries are not significantly abnormal
Micro myocardial hypertrophy/fibrosis
May be thrombi
What are the causes of dilated cardiomyopathy?
Idiopathic 30 percent genetic Past myocarditis Alcohol or other drug toxicity e.g. Doxorubicin Pregnancy associated Haemochromatosis Sarcoidosis
What are the clinical signs of dilated cardiomyopathy?
Occurs at any age but especially 20-50
Progressive congestive cardiac failure
Signs of LVF and RVF
Death from heart failure or sudden cardiac death via arrhythmia
What is the treatment for dilated cardiomyopathy?
Heart transplant
What are the features of hypertrophic cardiomyopathy?
Poor diastolic filling
Often outflow obstruction
Little to no dilation
Classical disproportionate thickening of septa, especially sub aortic
Micro hypertrophy p, disarray and fibrosis
What is the aetiology of hypertrophic cardiomyopathy?
Mutation of muscle protein especially beta myosin heavy chain, this leads to poor compliance and reduced left ventricular chamber size with possible outflow obstruction
Mostly familial
Many different mutations found
What do people die from in dilated or hypertrophic cardiomyopathy?
Heart failure
Stroke
Atrial fibrillation
Sudden death from arrhythmia
What are the features of restrictive cardiomyopathy?
Primary decrease in vascular compliance
Idiopathic
Firm normal sized ventricles with dilated atria
Secondary to irradiation fibrosis, amyloid, sarcoidosis, tumour metastasis (cause found with LM)
What is myocarditis?
Inflammation causing myocardial injury
Which viruses can cause myocarditis?
Cocksackie
Enteroviruses
HIV
Which bacteria typically cause myocarditis?
Chlamidya
Rickettsiae
Other than viruses and bacteria, which pathogens may cause myocarditis?
Fungi
Protozoa
Helminths
What are the immunological causes of myocarditis?
Post viral infection SLE Drug reactions Transplant reaction Sarcoidosis and giant cell myocarditis (more rare)
What is the aetiology of myocarditis?
Direct damage or T cell mediated injury to antigens on myocyte surface causing inflammation and myocyte necrosis
How might myocarditis present clinically?
May mimic acute infarct clinically
May lead to dilated cardiomyopathy
Arrhythmia, sudden death, fatigue, fever, chest discomfort, heart failure
What is the aetiology of ischaemic heart disease?
95 percent of cases are coronary artery atheroma
Coronary artery vasculitis
Coronary artery vasospasm
What is the aetiology of ischaemic heart disease due to thrombus?
Encrustation (rokitansky) - platelets thrombi over injured endothelium
Imbibition (Virchow) - low grade inflammation leads to increased plasma filtration
Reaction to injury (Ross and glomset) - endothelial injury with increased permeability and macrophage and smooth muscle accumulation
Monoclonal hypothesis - smooth muscle cells
What are the complications of ischaemic heart disease?
Ulceration Fissuring Haemorrhage Thrombosis Aneurysm
What are the throw types of acute myocardial infarct?
Transmural and subendocardial
What is a transmutation infarct?
Involves whole of the ventricular wall
The underlying lesion is an atheromatous plaque that undergone fissuring and occlusive thrombosis
What is a subendocardial infarct?
Confined to the inner third or half of the myocardium and results from generalised under perfusion of the myocardium
If the main left coronary artery is occluded, where would the sit of the MI be?
Massive anterolateral MI
If there was an occlusion in the left anterior descending artery where would the MI be?
Anteroseptal MI
If there was an occlusion in the left circumflex artery, where the MI be?
Lateral MI
If there was an occlusion in the right coronary artery where would the MI be?
Posterior inferior MI
How does a MI appear macroscopically and on histology if it has lasted 0-12 hours?
No changes
How does an MI appear visually aft 12-24 hours?
Pale with blotchy discolouration
How does the histology appear with a MI that has lasted 12-24 hours?
Bright eosinophilia of muscle fibres reflecting onset of coagulation necrosis
Intracellular oedema
How does a MI appear macroscopically if it has lasted 24-72hr?
Soft, pale and yellow
What is the histological appearance of an infarct lasting 24-72 hours?
Coagulation necrosis with loss of nuclei and strait ions, beginning of acute inflammatory response with neutrophil infiltrate
How does an MI macroscopically after 3-10 days
Soft, yellow - brown border with hyperaemic border
How does an MI appear histologically after 3-10 days?
Replacement of infarct end area with granulation tissue
How does an MI appear after weeks to months?
White fibrous scar
How does an MI appear histologically after weeks to months?
Collagenous scar tissue
What are the long term complications of MI?
Intractable heart failure
Ventricular aneurysm
Dressler’s syndrome
Recurrent MI
What factors may influence the severity of a PE?
Size of occluded vessel
No. Emboli
Adequacy of bronchial blood supply
What is a saddle emboli?
Embolus in the pulmonary trunk leading to circulatory collapse