ischaemic heart disease Flashcards
what 3 diseases comprise cardiovascular disease?
- coronary heart disease
- cerebrovascular disease
- peripheral vascular disease
what are the controllable risk factors for CHD?
- cigarette smoking
- diabetes
- high blood pressure
- high cholesterol
- obesity
what are the non-controllable risk factors for CHD?
- age
- family history of premature coronary disease
- previous heart attack
what is ischaemic heart disease (IHD) caused by?
it occurs due to atherosclerotic plaque build up within or one of more coronary arteries, thereby obstructing myocardial blood flow
what does ischaemic heart disease lead to?
an imbalance between myocardial oxygen supply and demand
what is myocardial ischaemia?
when there is a restriction in the normal increase in coronary blood flow which should occur in response to an increase in myocardial oxygen demand
what are the clinical manifestations of IHD?
- asymptomatic
- stable angina
- acute coronary syndromes: unstable angina, NSTEMI, STEMI
- long term: heart failure, arrhythmia and sudden death
what is the pathology of stable angina?
ischaemia due to fixed atheromatous stenosis of one or more coronary arteries
what is the pathology of unstable angina?
ischaemia caused by dynamic obstruction of a coronary artery due to plaque rupture with superimposed thrombosis and spasm
what is the pathology of myocardial infarction?
myocardial necrosis caused by acute occlusion of a coronary artery due to plaque rupture and thrombosis
what is the pathology of heart failure?
myocardial dysfunction due to infarction or ischaemia
what is the pathology of arrhythmia?
altered conduction due to ischaemia or infarction
what is the pathology of sudden death?
ventricular arrhythmia, asystole or massive myocardial infarction
what are the 3 characteristics of stable angina?
1) substernal chest discomfort of characteristic quality and duration
2) provoked by exertion or emotional stress
3) relieved by rest and/or nitrates within minutes
what conditions are included in acute coronary syndromes?
unstable angina and acute myocardial infarctions (STEMI and NSTEMIs)
how do you differentiate the difference between an acute MI, STEMIs and NSTEMIs?
the specific pattern of abnormality on the ECG
what cardiac enzyme is found in a raised level in patients who have an acute MI?
troponin
when is troponin released into the blood?
following an injury to the heart muscle and is diagnostic marker of an acute MI
when are troponin levels not rised?
in unstable angina
what is ACS characterised by?
the development of a thrombosis at the site of acute disruption of an atherosclerotic plaque within the wall of the coronary artery
after plaque disruption what does a thrombus result from?
- adherence activation and aggregation of platelets
- thrombin and fibrin production via the coagulation cascade (and thrombin release from platelets)
- vasoactive molecules released from platelets which cause vasoconstriction
what are the classical symptoms of ACS?
- discomfort/pain in the centre of the chest that lasts for more than a few minutes or recurs
- discomfort/pain radiating to other areas
- can occur at rest and/or with exertion
- not relieved immediately with sublingual GTN
what symptoms do the elderly or diabetic patients present with when suffering with ACS?
- breathlessness
- nausea or vomiting
- sweating and clamminess
what immediate assessment do you perform on patients with suspected ACS?
first: patient history, ECG and physical examination
then: risk stratification, cardiac biomarkers (troponin)
what do you ask when taking a patient history for someone with suspected ACS?
- nature and site of pain
- time of onset of pain and duration
- history of cardiovascular disease/risk factors
what are the therapeutic goals for ACS?
- restore coronary artery patency (STEMI)
- limit myocardial necrosis (STEMI)
- controls symptoms
what are the medical management for ACS?
- anti-platelet therapy
- anti-ischemic therapy
- secondary prevention therapy
what is used as anti-platelet therapy?
- aspirin
- clopidogrel/prasugrel/ticagrelor
what is used as anti-ischaemic therapy?
nitrates
what is used as secondary prevention therapy for ACS?
- statin
- ACE inhibitors
- beta blockers
- smoking cessation
- lifestyle modification
what are the 3 guidelines to manage STEMI?
1) timely diagnosis of STEMI is the key to successful management
2) the most critical time is the very early phase when the patient is liable to cardiac arrest
3) minimising delays to treatment is associated with improved clinical outcome
what is given for the rapid treatment in STEMIs?
- morphine and/or nitrates for pain relief
- anti-platelet agents (aspirin + clopidogrel)
AND - emergency primary angioplasty: artery is mechanically reopened restoring blood flow
- “clot-busting” drug: pharmacologically break up clots restoring blood flow
what is unstable angina?
- angina at rest
- new onset exertional angina
- recent acceleration of progression of angina symptoms
- normal cardiac biomarkers (troponin)
what is NSTEMI?
absence of ST elevation on ECG, but with fine symptoms and elevated cardiac biomarkers (troponin)
what could be other causes of positive troponin?
- pneumonia
- pulmonary embolism
- pericarditis
- sepsis
- heart failure
- uncontrolled tachyarrhythmia
what conditions make you more susceptible to ACS?
- elevated troponin levels
- renal impairment
- recurrent chest pain
- dynamic ST depression or at wave changes on ECG
- haemodynamic instability
- major arrhythmias
- heart failure
- elderly
how do you manage NSTEMI?
- analgesia
- anti-platelet therapy
- anti-ischaemic therapy
- statins
- early coronary angiography with a view to revascularisation
