Cardiovascular Flashcards
Ischaemic heart disease definition
Inadequate blood supply caused by an imbalance between the supply and demand of oxygen (and other nutrients) to the heart tissue. Divided into three segments: 1. Angina 2. Acute coronary syndrome 3. Myocardial infarction
Ischaemic heart disease aetiology
Restriction of blood flow to a region of myocardium may be caused by:
- atheroma
- thrombosis
- spasm
- embolus
- coronary ostial stenosis
Decrease in supply of oxygenated blood to the myocardium:
- anaemia
- hypotension (decreased flow to heart)
- hypoxemia
Increased demand of heart tissue:
- hypertension
- tachyarrhythmia
- valvular heart disease
- hyperthyroidism
- hypertrophic cardiomyopathy
Myocardial ischaemia most commonly occurs due to obstructive coronary artery disease (CAD) in the form of coronary atherosclerosis
Ischaemic heart disease risk factors
Modifiable:
- diabetes mellitus
- hyperlipidemia
- hypertension
- kidney disease
- obesity
- physical inactivity
- cigarette smoking
- alcohol
Non-modifiable
- age
- family history (not relevant if occured over 55yrs old)
- male (oestrogen in women is protective)
Environmental exacerbating factors:
- cold weather
- heavy meals
- emotional stress
Ischaemic heart disease pathophysiology
look at myles’ table
Angina definition
A major symptom of stable IHD. Characterised by chest pain. Main types are stable and unstable.
Angina aetiology
Stable angina:
narrowing of the artery from a plaque - symptoms felt at >70% occlusion
Unstable angina:
likely due to the development of a thrombus from plaque rupture. Comes under the umbrella term of acute coronary syndromes
Angina risk factors
same as atherosclerosis
Angina signs and symptoms
Stable angina:
- central chest pain on exertion
- relieved by GTN spray
- radiation of pain to neck, jaw and arm
Untable angina:
- new onset pain without exertion
- gets worse quickly
- GTN spray does not relieve symptoms
Angina 1st line investigations
Stable:
- resting ECG - often normal, may reveal ST-T changes (St depression and T wave inversion) suggestive of ischaemia or Q waves indicative or prior infarction
- Lipid profile - usually raised LDLs
Unstable:
- ECG - may be normal or have transient ST segment depression or T wave inversion
- cardiac biomarkers - troponin not usually elevated as there is no acute myocardial damage
Angina gold standard investigations
Stable: perfusion MRI
- less available but best option
- CT coronary angiography not great at determining severity
Unstable: coronary angiography is the gold standard for assessing the presence and severity of CAD and allows for concurrent treatment with angioplasty and stenting if needed.
Angina differential diagnosis
Other anginas:
- prinzmetal’s angina - coronary artery syndrome
- microvascular angina - syndrome X - predominantly women, abnormal structure causing increased resistance
- crescendo angina - artery becomes so narrow blood struggles to flow even at rest
- unstable vs stable
Chest pain not related to myocardial ischaemic: - preicarditis/myocarditis - pulmonary embolism/pleurisy - chest infection/pleurisy - dissection of the aorta - GORD, spasm or ulceration - musco-skeletal psychological
Angina management
Stable (prevent it becoming unstable):
- education for lifestyle factors - smoking, weight, exercise, diet…
- anti platelet therapy - aspirin and clopidogrel or other P2Y12 inhibitor
- lipid-lowering therapy - primary options are statins - secondary are ezetimibe or alirocumab
- beta blocker
- sublingual GTN
- antihypertensives - beta-blockers and ACE inhibitors or angiotensin-II receptor antagonists
- blood sugar control (if needed)
- percutaneous Coronary Intervention (PCI) (for more severe cases)
Unstable (for ongoing confirmed unstable angina):
- may have PCI
Antiplatelet therapy - aspirin + P2Y12 inhibitor, may consider GPIIb/IIIa antagonists
- statin +/- ezetimibe
- beta blocker
- ACE inhibitor
- lifestyle education
May also consider ca++ channel blockers for underlying HTN
Angina prognosis
Reasonably good
Very low death rate per annum considering age
- cardiovascular events (includes non-fatal MIS, hospital admissions etc) a bit higher
- reassure patients diagnoses with angina
Acute coronary syndrome (NSTEMI) definition
Non-ST elevation myocardial infarction.
Myocardial infarction occurs when cardiac myocytes die due to myocardial ischaemia. NSTEMIs are usually a retrospective diagnosis made after troponin results and sometimes other investigations (echocardiogram, cardio angiogram)
NSTEMI aetiology
NSTEMIs are usually a result of a transient or near-complete occlusion of a coronary artery or acute factor that deprives myocardium of oxygen. Different from a STEMI as there is not usually complete occlusion of the affected coronary artery
NSTEMI risk factors
see unstable angina
NSTEMI pathophysiology
common mechanism of all ACS is rupture or erosion of the fibrous cap of a coronary artery plaque. This leads to platelet aggregation, localised thrombosis, vasoconstriction and distal thrombus embolisation.
NSTEMI key presentations
New onset of chest pain or chest pain at rest or a deterioration of preexisting angina.
NSTEMI signs and symptoms
Often retrosternal pain radiating to the left arm but may also radiate to the lower jaw, neck, both arms, back and epigastrium.
GTN trial: ongoing pain
Angiography should be considered if high risk
NSTEMI 1st line investigations
ECG:
- ST depression
- T wave inversion
- Usually pretty normal so diagnosed by troponin
- FBC
- Troponin: high, >99th percentile of normal.
- Elevated troponin is sign of infarction
- U&Es
- Glucose
- Lipids
- CXR - DDx
NSTEMI gold standard investigations
Urgent coronary angiography for diagnoses and treatment in patients at a high risk for progression to MI or death.
NSTEMI differential diagnosis
Can be distinguished from unstable angina by troponin levels Aortic dissection PE Peptic ulcer Acute pericarditis Psychological Stable ischaemic heart disease
NSTEMI management
Acute presentation:
- antiplatelet therapy
- oxygen
- GTN
- beta-blocker
- calcium channel blocker
- assess need for PCI
- heparin
- GPIIa/IIb inhibitor
Intermediate management: M- morphine N- nitrates vasodilator A- aspirin stops the platelets sticking together C- clopidogrel AntiPlatelet drug
STEMI definition
Acute myocardial infarction is myocardial cell death occurring due to a prolonged mismatch between perfusion and demand. In the case of ST-elevation MI this is caused by complete atherothrombotic occlusion of a coronary artery.