Theme 3: Lecture 7 - Ischaemic heart disease Flashcards
What comprises cardiovascular disease
- Coronary heart disease
- Cerebrovascular disease
- Peripheral vascular disease
Coronary heart disease
Build up of cholesterol deposits in the coronary arteries
Cerebrovascular disease
Build up of cholesterol deposits in the arteries supplying the brain
Peripheral vascular disease
Build up of cholesterol deposits in arteries of the lower limb
Controllable risk factors for CHD
Cigarette Smoking Diabetes High blood pressure High cholesterol Obesity
Non controllable risk factors for CHD
Age
Family history of premature coronary disease
Previous heart attack
According to the Framingham heart study, does your risk of CHD increase with an increasing number of risk factors
yes
How does ischaemic heart disease cause myocardial ischaemia
- IHD occurs due to atherosclerotic plaque build up within one or more coronary arteries, obstructing myocardial blood flow
- This leads to an imbalance between myocardial oxygen supply and demand
- Restricts the normal increase in coronary blood flow which should occur in response to increase in myocardial oxygen demand
What are the clinical manifestations of ischaemic heart disease (8)
- Asymptomatic
- Stable angina
- Acute coronary syndromes (Unstable angina, NSTEMI, STEMI)
Long-term:
- Heart failure
- Arrhythmias
- Sudden death
What pathology causes unstable angina
ischaemia caused by dynamic obstruction of a coronary artery due to plaque rupture with superimposed thrombosis and spasm
Definition of typical angina
Meets all 3 of the following criteria:
- substernal chest discomfort of characteristic quality and duration
- provoked by exertion or emotional stress
- relieved by rest and/or nitrates within minutes
Definition of atypical angina
Meets 2 of the following criteria:
- substernal chest discomfort of characteristic quality and duration
- provoked by exertion or emotional stress
- relieved by rest and/or nitrates within minutes
Definition of non anginal chest pain
Lacks or only meets one of these criteria:
- substernal chest discomfort of characteristic quality and duration
- provoked by exertion or emotional stress
- relieved by rest and/or nitrates within minutes
First line treatment for angina relief
Short acting nitrates plus:
-beta blockers or calcium channel blockers
-
What is second line treatment for angina
consider PCI stenting or CABG
What do acute coronary syndromes include
- unstable angina
- MI (STEMI and NSTEMI)
What is the diagnostic marker for an acute MI
Troponin which is measured in a blood test
When are troponin levels elevated
- In acute MI
- Not in unstable angina
How are STEMIs and NSTEMIs differentiated
by the specific pattern of abnormality on the ECG
What is ST elevation on an ECG a marker of generally
complete coronary occlusion
What is incomplete occlusion associated with on an ECG
- ST depression
- Variable T wave abnormalities
- Normal ECG
How to acute coronary syndromes develop
ACS is characterised by the development of a thrombosis at the site of acute disruption of an atherosclerotic plaque within the wall of the coronary artery
How do thrombi develop following plaque disruption in an artery
- 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 acute coronary syndromes
- Discomfort/pain in the centre of the chest that lasts for more than a few minutes or recurs
- Discomfort/pain radiating to other areas, e.g. left arm/jaw/back
- Can occur at rest and/or with exertion
- Not relieved immediately with sublingual GTN
What are symptoms seen in elderly or diabetic patients with acute coronary syndromes
- Breathlessness
- Nausea or vomiting
- Sweating and clamminess
Immediate assessment of patients with suspected ACS
First: -Patient history -ECG -Physical examination Then/in parallel: -Risk stratification -Cardiac biomarkers (troponin)
What are the goals for patients with coronary artery syndromes
- Restore coronary artery patency (being open/unobstructed)
- Limit myocardial necrosis
- Control symptoms
What is the medical management in acute coronary syndromes
- Anti-platelet therapy
- Anti-ischaemic therapy
- Secondary prevention therapy
Which drugs are used in anti-platelet therapy
- Aspirin
- Clopidogrel /Prasugrel /Ticagrelor (P2Y12 receptor antagonists which is a receptor for ADP)
Which drugs are used for anti-ischaemic therapy
Nitrates
What is used in secondary prevention therapy
- Statin
- ACE inhibitors
- Beta blockers
- Smoking cessation
- Lifestyle modification
Treatment for STEMI
-Morphine and/or nitrates for pain relief
-Antiplatelet agents (aspirin + clopidogrel)
AND
-Primary angioplasty (balloons, stents): artery is mechanically reopened, restoring blood flow
-“Clot-busting” drug (thrombolysis): pharmacologically break up clots, restoring blood flow (when no access to primary angioplasty)
Definitions for unstable angina
- Angina at rest (> 20mins)
- New onset (< 2 months) exertional angina
- Recent (< 2months) acceleration or progression of angina symptoms
- Normal cardiac biomarkers (troponin)
Definition of an NSTEMI
Defined as the absence of ST elevation on ECG, but with angina symptoms and elevated cardiac biomarkers (troponin)
What other conditions is a positive troponin seen in other than MI (6)
- Pneumonia
- Pulmonary embolism
- Pericarditis
- Sepsis
- Heart Failure
- Uncontrolled tachyarrhythmia
Who are high risk ACS patients (8)
- Elevated troponin levels
- Renal impairment
- Recurrent chest pain
- Dynamic ST depression or T wave changes on ECG
- Haemodynamic instability
- Major arrhythmias
- Heart failure
- Elderly
How are unstable angina and NSTEMIs treated
- Analgesia
- Anti-platelet therapy
- Anti-ischaemic therapy
- Statins
- Early coronary angiography with a view to revascularisation (stenting or CABG)
What pathology causes stable angina
Ischaemia due to fixed atheromatous stenosis of one or more coronary arteries
What pathology causes MI
myocardial necrosis caused by acute occlusion of coronary artery due to plaque rupture and thrombosis
What pathology causes heart failure
myocardial dysfunction due to ischaemia or infarction
What pathology causes arrhythmia
altered conduction due to ischaemia or infarction
What pathology causes sudden death
ventricular arrhythmia, asystole or massive myocardial infarction
