Cardiovascular Flashcards
MI (NSTEMI) Definition
- Acute ischaemic event causing myocyte necrosis
- Initial ECG may show ischaemic changes such as ST depressions, T-wave inversions or transient ST elevations – may also be normal or show non-specific changes
how common is an MI (NSTEMI)
• CVD is the number one cause of death worldwide
affects mainly men
causes of an MI (NSTEMI)
• Result of an acute imbalance between myocardial oxygen demand and supply, most commonly due to a reduction in myocardial perfusion
• Several different sequences of events that may lead to an NSTEMI:
- Plaque rupture with superimposed non-occlusive thrombus or embolic events leading to coronary vascular obstruction MOST COMMON CAUSE
- Dynamic obstruction, such as in vasospasm
- Progressive luminal narrowing (i.e. chronic arterial narrowing from restenosis)
- Inflammatory mechanisms i.e. vasculitis
- Extrinsic factors leading to poor coronary perfusion (such as hypotension, hypovolaemia or hypoxia)
Risk factors for an MI (NSTEMI)
- Atherosclerosis
- Diabetes
- Smoking
- Dyslipidaemia
- Age >65yrs
- HBP
- Cocaine use
- Depression
Symptoms/ signs for an MI (NSTEMI)
- Presence of risk factors
- Chest pain tightness, heaviness, aching, burning, pressure or squeezing – pain is most often retrosternal and can often radiate to the left arm, lower jaw, neck etc
- Diaphoresis – sweating to an unusual degree
- Abdo pain
- HBP
- N&V and SOB
- Physical exertion
- Diabetics may not have chest pain
DDx for MI (NSTEMI)
- STEMI
- Aortic dissection
- PE
- Peptic ulcer disease
- Acute pericarditis
- Oesophageal spasm
- Costochrondritis
Investigation for MI (NSTEMI)
• 1st LINE:
- ECG: non-specific ST-T wave changes or ischaemic changes
- TRIAL OF SUBLINGUAL GLYCERYL TRINITRATE: ongoing pain
- CARDIAC TROPONIN: test is more specific than CK-MB or myoglobin and is the best marker for msk injury and small MI - >99th percentile of normal
- CK: >99th percentile of normal
- CK-MB: - >99th percentile of normal
- FBCs, U&E’s, Serum Creatinine, LFTs, blood glucose
- CXR: may show pulmonary oedema
Management for MI (NSTEMI)
• 1st LINE:
- MONA – morphine, oxygen (only if <94% sats), nitrates (GTN), aspirin
- Aspirin: orally
- If aspirin-intolerant clopidogrel
- Give oxygen if O2 sats below 90%
- PLUS: beta-blocker, calcium-channel blocker, glyceryl trinitrate
prognosis and complications for MI (NSTEMI)
- CVD responsible for about 30% of UK deaths
- Cardiac arrhythmias, depression, CHF, cardiogenic shock
definition of MI (STEMI)
- Myocardial cell death that occurs because of a prolonged mismatch between perfusion and demand
- Usually caused by occlusion in the coronary arteries
- ST-elevation MI is suspected when a patient presents with persistnet ST-segment elevation in 2 or more anatomically contiguous ECG leads in the context of a consistent clinical history
How common is MI (STEMI)
- CVD responsible for about 30% of UK deaths
- MIs are 3 times more likely in men than women
causes of MI (STEMI)
- Atherosclerotic plaques form gradually over years
- They begin with the accumulation of low-density lipoprotein cholesterol and saturated fat in the intima (inner layer) of blood vessels
- Followed by the adhesion of leukocytes t the endothelium, then diapedesis and entry into intima where they accumulate lipids and become foam cells – rich source of proinflammaotry mediators FATTY STREAK
- Subsequent evolution involves migration of smooth muscle cells from the media, and their proliferation and deposition of extracellular matrix including proteoglycans, interstitial collagen and elastin fibres – some of the smooth muscle cells in advanced plaques exhibit apoptosis – plaques often develop calcification spots as they evolve eventually causes arterial occlusion and stenosis
- STEMI typically occurs after abrupt and catastrophic disruption of a cholesterol-laden plaque - this results in exposure of substances that promote platelet activation and aggregation, thrombin generation, and thrombus formation, causing interruption of blood flow
- If the occlusion is severe and persistent, myocardial cell necrosis follows
- On interruption of blood flow in the coronary artery, the zone of myocardium supplied by that vessel immediately loses its ability to shorten and perform contractile work
- Early hyperkinesis of the non-infarcted zones occurs, probably as a result of acute compensatory mechanisms including increased sympathetic activity and Frank-Starling mechanism
- As necrotic myocytes slip past each other, the infarction zone thins and elongates, especially in anterior infarction, leading to infarction expansion
risk factors for MI (STEMI)
- Hypertension
- Smoking
- Diabetes
- Obesity
- Metabolic syndrome
- Physical inactivity
- Dyslipidaemia
- Renal insufficiency
- Established coronary artery disease
- Fx of premature coronary artery disease
- Cocaine use
- Male sex
- Advanced age
symptoms/signs for MI (STEMI)
- Chest pain - diabetics may not have chest pain
- Dyspnoea
- Pallor
- Diaphoresis – common feature associated with MI due to high sympathetic output
- Nausea
- Vomiting
- Dizziness
- Weakness
- Tachycardia
- Additional heart sounds audible S3 or S4 on cardiac exam indicates poor cardiac muscle compliance of the infarcted muscle
DDx for MI (STEMI)
- Unstable angina
- NSTEMI
- Aortic dissection
- PE
- Pneumothorax
- Pneumonia
- Pericarditis
- Myocarditis
- GORD
Investigations for MI (STEMI)
• 1ST LINE:
- ECG: if ECG shows ST-segment elevation, the patient should be urgently assessed for reperfusion therapy
- CARDIAC BIOMARKERS: elevated troponin
- GLUCOSE: hyperglycaemia is common in the setting of acute MI, with or without a history of diabetes – normal or elevated levels
- U&E’s: determines if any disturbances that may need management are present – may be abnormal
- SERUM LIPIDS: cholesterol levels may be lowered by high catecholamine levels produced by the MI in its early phases – need ot be repeated in 30-60 days – normal or elevated levels
- CXR: widened mediastinum suggests aortic dissection, pulmonary oedema indicates impaired cardiac function
- CORONARY ANGIOGRAM: presence of thrombus with occlusion of the artery
Management for MI (STEMI)
• 1ST LINE: - ASPIRIN: orally o Give oxygen if O2 sats below 90% o If ongoing chest pain give morphine • If unstable revascularisation (PCI) or coronary artery bypass graft (CABG)
Prognosis or complications for MI (STEMI)
Prognosis - about 15% who have an acute MI will die from it
complications - sinus bradycardia, complete heart block with anterior MI, recurrent chest pain
Acute Coronary Syndrome definition
- Refers to a spectrum of acute MI or infarction
- Divivded into three clinical categories according to the presence or absence of STEMI, NSTEMI and unstable angina
- Syndrome which describes decreased blood fow in the coronary arteries such that part of the heart muscle is unable to function properly or dies
- Depending on the tests this can go from: ECG ST-elevation or no ST-elevation, unstable angina from cardiac markers if pos, neg it is MI and either NSTEMI or STEMI
Angina (Stable) definition
- SHID and low-risk unstable angina are most commonly caused by atheromatous plaques in the coronary arteries that obstruct blood flow
- Anginal symptoms are a clinical manifestation of ischaemia
- Key contributory factors to progression of atheromatous disease include smoking, hypertension, hyperlipidaemia, diabetes and obesity
how common is Angina (Stable)
prevalence is unclear
higher in males than females
causes of Angina (Stable)
- Atheromatous plaque leading to obstruction of coronary blood flow is the most common cause
- Damage to the aterial wall produces an inflammatory response and the development of atheromatous plaques
- Exposure of the arterial endothelium to low-density lipoproteins results in the expression of adhesion molecules that allow leukocytes to stick to the arterial wall
- Upon entry into the artery wall, blood monocytes begin to scavenge lipids and become foam cells
- Macrophage foam cells release additional cytokines and effector molecules that stimulate smooth muscle migration from the arterial media into the intima, as well as smooth muscle cell proliferation
- In this process, the initial fatty deposition of lipoprotein in the arterial intima develops ito atherosclerotic plaques
- Ischaemic symptoms may result from obstruction of blood flow due to atherosclerotic plaques or when a clot or vasospasm is superimposed on less severe plaques
risk factors for Angina (Stable)
- Advancing age
- Smoking
- Hypertension
- Elevated LDL cholesterol
- Isolated low HDL cholesterol
- Diabetes
- Inactivity
- Obesity
- Male
symptoms/signs of Angina (Stable)
- Presence of risk factors
- Typical angina symptoms – chest pressure or squeezing lasting several minutes, provoked by exercise or emotional stress and relieved by res or GTN
- Atypical angina symtpoms – chest discomfort with only 2 characteristics of typical angina
- Features of low-risk unstable angina include pain from exertion lasting less than 20 minutes, pain not rapidly increasing and normal/unchanged ECG
DDx of Angina (Stable)
- PE
- Pericarditis
- Aortic dissection
- Pneumothorax
Investigations for Angina (Stable)
- Lymph node examination
- If unexplained consider a very urgent FBC
- In people >40, with supraclavicular lymphadenopathy or persistent cervical lymphadenopathy, consider an urgent chest X-ray
Management of Angina (Stable)
• 1st LINE:
- CALCIUM CHANNEL BLOCKER OR BETA BLOCKER FIRST LINE
- LIFESTYLE EDUCATION
- ANTIPLATELET THERAPY: aspirin or clopidogrel
- ANTI-ANGINAL THERAPY: bisoprolol
- STATIN: atorvastatin
- ANTIHYPERTENSIVE: bisoprolol
- Acute give GTN – careful with phosphodiesterase inhibitors (contraindicated)
Prognosis and complications of Angina (Stable)
prognosis - patients can expect a reduction in angina symptoms
complications - chronic heart failure, MI, stroke, depression
Angina (Unstable) Definition
• ACS that is defined by the absence of biochemical evidence of myocardial change
how common is Angina (Unstable)
CVD is the number one cause of death globally for men and women
affects mainly adults
causes of Angina (Unstable)
- CAD is the underlying cause in nearly all pts with acute MI
- Most common cause of UA is due to CA narrowing caused by a thrombus that develops on a disrupted atherosclerotic plaque and is usually non-occlusive
- Less common cause is intense vasospasm of a CA (variant or Prinzmetal’s angina) – intense vasospasm is caused by vascular smooth muscle or by endothelial dysfunction
risk factors for Angina (Unstable)
- Female
- Personal history of CAD
- Increased age
- Fx of CAD
- Hypertension
- Smoking
- Diabetes
- Hyperlipidaemia
- PVD
Symptoms of Angina (Unstable)
- Presence of risk factors
- Increasing frequency of chest pain – pain occurs daily or several times a day
- Increasing severity of chest pain – decreasing levels of activity needed to trigger chest pain and may occur at rest
- Retrosternal chest pain radiating to jaw, arm or neck – retrosternal pressure or heaviness radiating to the jaw, arm or neck that is relieved or improved by nitrates
- Dyspnoea
- Fourth heart sound (S4)
signs of Angina (Unstable)
• 3 key symptoms:
- Constricting discomfort in the front of the chest, in the neck, shoulders, jaw, or arms
- Precipitated by physical exertion
- Relieved by rest or GTN within about 5 minutes
• Typical angina has all 3, atypical have 2/3, people with non-anginal chest pain have one or none of the 3 features.
DDx of Angina (Unstable)
- Stable angina
- STEMI/NSTEMI
- CHF
- Chest wall pain
- Pericarditis
- Myocarditis
- Aortic dissection
- PE
Investigations for Angina (Unstable)
• 1st LINE:
- ECG: may be normal or have transient ST segment depression or T-wave inversion
- CARDIAC BIOMARKERS: not elevated
- FBC: normal
- ELECTROLYTES AND RENAL FUNCTION: normal
- BLOOD SUGAR: normal, elevated in the presence of diabetes
- LIPID PROFILE: increased
- COAGULATION: normal
- CXR: pulmonary oedema
- CORONARY ANGIOGRAPHY: gold standard for assessing the presence and severity of CAD, and allows concurrent tx with angioplasty and stenting
Management for Angina (Unstable)
• 1st LINE:
- PRESUMED CARDIAC CHEST PAIN: oxygen, nitrates (GTN) and morphine
- CONFIRMED UNSTABLE ANGINA: antiplatelet therapy aspirin (without stenting), clopidogrel (with stenting), + statin + beta blocker + ACEi
Prognosis and complications for Angina (Unstable)
Prognosis - dependant on cause
complications - Bleeding, thrombocytopenia, CHF, ventricular arrhythmias
AF definition
- Supraventricular tachyarrhythmia
- Characterised by uncoordinated atrial activity on the surface ECG, with fibrillatory waves of varying shape, amplituds and timing associated with an irregularly irregular ventricular response when AV conduction is intact
how common is AF
- 0.5-1% prevalence
* Elderly patients, higher prevalence in men than women 1.5:1 M:F
Causes of AF
- AF is usually associated with anatomically and histologically abnormal atria as a result of underlying heart disease
- Dilation of the atria with fibrosis and inflammation causes a difference in refractory periods within the atrial tissue and promotes electrical re-entry that results in AF
- Presence of rapidly firing foci, typicall in the pulmonary veins, may trigger AF and this is sutained by firbillatory conduction or multiple re-entrant circuits
risk factors of AF
- Hypertension
- CAF
- CHF
- Advancing age
- Diabetes
- Rheumatic valvular disease
- Alcohol abuse
- Male sex
- Presence of other arrhythmias
- Smoking
symptoms/ signs of AF
- Presence of risk factors
- Palpitations
- Tachycardia
- Irregular pulse
- Stroke – complication of AF
DDx of AF
- AF with variable AV conduction
- Multifocal atrial tachycardia
- Atrial tachycardia with variable AV conduction
Investigations of AF
• 1ST LINE:
- ECG: absent P-waves, presence of fibrillatory waves that vary in size, shape and timing, irregularly irregular QRS complexes
- THYROID PROFILE: suppressed TSH if hyperthyroidism thyrotoxicosis may present with AF
- ECHOCARDIOGRAM: may have valvular regurgitation or stenosis, left ventricular or atrial enlargement, peak right ventricular pressure (pulmonary HTN), left ventricular wall thickness and function
- SERUM UREA AND ELECTROLYTES (INCLUDING SERUM MAGNESIUM): may be normal, may be abnormal with renal dysfunction
management of AF
• 1st LINE:
- ANTICOAGULATION OR ANTIPLATELET THERAPY: warfarin
o + rate control: bisoprolol/propranolol (1st), digoxin/dilitazem (2nd)
Prognosis and complications of AF
Prognosis - depends on several factors
complications - stroke, hypotension, heart failure, exacerbation of reactive airway disease associated with beta-blocker therapy
Essential Hypertension definition
• Defined as BP >140/90mmHg with no secondary cause identified
how common is Essential Hypertension
- 1 billion people are hypertensive
- mainly adults, mainly men
causes of Essential Hypertension
- BP = CO x PVD affected by preload, contractility, vessel hypertrophy and peripheral constriction
- Pathology associated with and the perpetuation of the hypertensive state involves structural changes, remodelling and hypertrophy in resistance arterioles
- Changes have been associated with the early and progressive development of small vessel atherosclerosis which is probably the cause of end-organ damage seen in advanced hypertension
risk factors of Essential Hypertension
- Obesity
- Aerobic exercise <3 times/week
- Moderate/high alcohol intake
- Metabolic syndrome
- Diabetes
- Black ancestry
- Age >60 years
- Fx of hypertension or coronary artery disease
- Sleep apnoea
symptoms/signs of Essential Hypertension
- Presence of risk factors
- Blood pressure over 140/90mmHg
- Retinopathy
DDx of Essential Hypertension
- Drug-induced NSAIDs, oral contraceptive pill, immunosupressants, erythropoietin
- CKD
- Renal artery stenosis
- Aortic coarctation
- Hypothyroidism
- Hyperthyroidism
- Hyperparathyroidism
Investigations of Essential Hypertension
• 1st LINE:
- ECG: may show evidence of left ventricular hypertrophy or old infarction
- FASTING METABOLIC PANEL WITH ESTIMATED GFR: may show renal insufficiency, hyperglycaemia, hypokalaemia, hyperuricaemia or hypercalcaemia
- LIPID PANEL: may show high LDL, low HDL, or high triglycerides
- URINALYSIS: may show proteinuria
- Hb: anaemia or polycythaemia suggests secondary cause or complication
- TSH: high or low if thyroid dysfunction
Management of Essential Hypertension
• 1st LINE:
- Step 1:
o Younger than 55 ACE inhibitor
o Older than 55 or black of any age calcium channel blocker or thiazide-type diuretic
- Step 2: ACEi + calcium channel blocker or ACEi + thiazide-type diuretic (indapamide)
- Step 3: ACEi + calcium channel blocker + thiazide-type diuretic
- Step 4: Step 3+ a further diuretic therapy or α-blocker or β blocker - consider seeking specialist advice
Prognosis and complications of Essential Hypertension
prognosis - good when treated
complications - CAD, LVF, cerebrovascular accident, CHF, retinopathy
DVT definition
- Development of a blood clot in a major deeo vein in the leg, thigh, pelvis or abdomen, which may result in impaired venous blood flow and consequent leg swelling and pain
- Venous thrombosis may also occur in the upper extremities or in more unusual sites such as the portal, mesenteric, ovarian and retinal veins as well as the veins and venous sinuses of the brain
how common is DVT
1 in every 1000 adults
affects frequent flyers, obese people, higher in black people
causes of DVT
- Most blood clots that develop in the deep venous system of the leg begin to form just above and behind a venous valve
- Clots often resolve spontaneously but when the propagation of the trhombus does occur it expands and grows proximally and across the lumen of the vein
- A clot might occlude the entire lumen, but it is more commonly located on one peripheral aspect of the lumen
- Many DVTs arise in the calf veins and propagate proximally
risk factors of DVT
- Medical hospitalisation within the past 2 months
- Major surgery within 3 months
- Active cancer
- Severe or lower-extremity trauma
- Increasing age
- Pregnancy
- Factor V leiden
- Protein C, S or antithrombin deficiency