Ischaemic Heart Disease Flashcards
Define Ischaemic Heart Disease?
Characterised by decreased blood supply to the heart muscle resulting in chest pain (angina pectoris)
What are the two ways Ischaemic Heart Disease can present?
Stable angina or Acute Coronary Syndrome (ACS)
How can ACS be further subdivided into?
Unstable angina
NSTEMI
STEMI
What is unstable angina?
Chest pain at rest due to ischaemic but without cardiac injury
What is STEMI?
ST elevation with transmural infarction
What is MI?
Cardiac muscle necrosis resulting from ischaemia
What is the epidemiology of ischaemic heart disease?
Common
Prevalence > 2%
More common in males
Annual incidence of MI in the UK ~ 5/1000
When does Angina Pectoris occur?
When myocardial oxygen demand exceeds oxygen supply
What is Angina Pectoris due to?
Atherosclerosis
What are the rarer causes of angina pectoris?
Include coronary artery spasm (e.g. induced by cocaine)
Arteritis
Emboli
What is the pathophysiology of atherosclerosis?
Endothelial injury leads to migration of monocytes into the subendothelial space
These monocytes differentiate into macrophages
Macrophages accumulate LDL lipids and become foam cells
These foam cells release growth factors that stimulate smooth muscle, proliferation, production of collagen and proteoglycans
This leads to the formation of an atherosclerotic plaque
What are the risk factors for Ischaemic Heart Disease?
Male Diabetes Mellitus Family History Hypertension Hyperlipidaemia Smoking
What are the presenting symptoms of ACS?
Acute-onset chest pain
Central, heavy, tight, crushing pain
Radiates to the arms, neck, jaw or epigastrium
Occurs at rest
More severe and frequent pain that previously occuring stable angina
What are the associated symptoms of ACS?
Breathlessness
Sweating
Nausea and vomiting
Silent Infacts occur in the elderly and diabetics
What are the presenting symptoms of Stable Angina?
Chest pain brought on by exertion and relieved by rest
What are the signs of ACS on physical examination?
Pale Sweating Restless Low-grade pyrexia Check both radial pulses to rule out aortic dissection Arrhythmias Disturbances of BP New heart murmus Signs of complications
What are signs of complications of ACS on physical examination?
Acute heart failure
Cardiogenic Shock
What is important to remember when physically examining for ACS?
There may be no clinical signs
What bloods would you do for Ischaemic Heart Disease?
FBC U&Es CRP Glucose Lipid profile Cardiac enzymes (troponins and CK-MB) Amylase (pancreatitis could mimic MI) TFTs AST and LDH (raised 24 and 48 hours post-MI, respectively)
What do we see on an ECG for unstable Angina or NSTEMI?
May show ST depression or T wave inversion
What would we see on an ECG with STEMI?
Hyperacute T waves
ST elevation (> 1 mm in limb leads, > 2 mm in chest leads)
New-onset LBBB
Later changes: T wave inversion and Pathological Q waves
What is the relationship between ECG leads and the side of the heart?
Inferior: II, III, aVF
Anterior: V1-V5/6
Lateral: I, aVL, V5/6
Posterior: Tall R wave and ST depression in V1-3
How do we use CXR in ischaemic heart disease investigations?
Check for signs of heart failure
What are the indications for an Exercise ECG in Ischaemic Heart Disease?
Patient with troponin-negative ACS or stable angina with a high pretest probability of coronary heart disease
Pretest probability is based on characteristics of chest pain, cardiac risk factors, age and gender
Digoxin is associated with giving a false-positive result
What is the positive test of an Exercise ECG?
> 1mm horizontal or downsloping ST depression measured at 80 ms after the end of the QRS complex
What is the failed test for an Exercise ECG?
Failure to achieve at least 85% of the predicted maximal heart rate (220-age) and otherwise negative findings (no chest pain or ECG changes)
What are some resting ECG abnormalities?
pre-excitation syndrome
>1mm ST depression
LBBB or pacemaker ventricular rhythm
How do we use Radionuclide Myocardial Perfusion Imaging (rMPI)?
Uses Technetium-99m sestamibi or tetrofosmin
Can be performed under stress or at rest
Stress testing shows low uptake in ischaemic myocardium
How do we use an Echocardiogram in Ischaemic Heart Disease?
Measures left ventricular ejection fraction
Exercise or dobutamine stress echo may detect regional wall motion abnormalities
When do we do Pharmacological Stress Testing?
This is used in patients who are unable to exercise
Pharmacological agents can be used to induce a tachycardia
These agents are used in conjuction with various imaging modalities to detect ischaemic myocardium
What are the pharmacological agents that can be used to induce tachycardia?
Dipyridamole
Adenosine
Dobutamine
When are Dypiridamole and Adenosine contraindicated?
In AV block and reactive airway disease
When is Cardiac Catheterisation/Angiography used?
Perfomed if ACS with positive troponin or if high risk on stress testing
What is Coronary Calcium scoring and when is it used?
Uses specialised CT scan
May be useful in outpatients with atypical chest pain or in acute chest pain that isn’t clearly due to ischaemia
What is the management plan for Stable Angina?
Minimise cardiac risk factors Immediate symptom relief Long-term management Percutaneous Coronary Intervention (PCI) Coronary Artery Bypass Graft (CABG)
What are cardiac risk factors that should be minimised?
BP
Hyperlipidaemia
Diabetes
What should all patients receive?
Aspirin 75 mg/day unless contraindicated
What can be used for immediate symptom relief?
GTN spray
What is the long-term management of a stable angina?
Beta-Blockers
Calcium Channel blockers
Nitrates
When is Beta-blockers contraindicated?
Acute Heart Failure Cardiogenic Shock Bradycardia Heart Block Asthma
When is Percutaneous Coronary Intervention (PCI) performed?
In patients with stable angina despite maximal tolerable medical therapy
What is an example of a situation when CABG is done?
Occurs in more severe cases
E.g. three-vessel disease
What is the management plan for unstable angina/NSTEMI?
Admit to coronary care unit Oxygen, IV access, monitor vital signs and serial ECG GTN Morphine Metroclopramide Aspirin Clopidogrel LMWH Beta-Blocker Glucose-Insulin infusion
Why do we adminster Metoclopramide?
To counteract the nausea caused by morphine
Wnat is the Aspirin dose in the treatment of Unstable Angina/NSTEMI?
300 mg initially, followed by 75 mg indefinitely
What is the Clopidogrel dose for the treatment of Unstable Angina/NSTEMI?
300 mg initially, followed by 75mg for at least 1 year if troponin positive or high risk
When do we do a Glucose-insulin infusion in the treatment of Unstable Angina/NSTEMI?
If blood glucose > 11 mmoll/L
Why might we consider GlpIIb/IIIa inhibitors in patients with Unstable Angina/NSTEMI?
In patients:
undergoing PCI
At high risk of further cardiac events
What do we do if there is little improvement following treatment of an Unstable Angina/NSTEMI?
Consider urgent angiography with/without revascularisation
What is a mneumonic to remember the acute management of ACS?
MONOBASH: Morphine Oxygen Nitrates Anticoagulants (aspirin + clopidogrel) Beta-blockers ACE inhibitors Statins Heparin
What is the difference between STEMI management and UAP/NSTEMI management?
Clopidrogrel
600mg if patient is going to PCI
300 mg if undergoing thrombolysis and < 75 yrs
75mg if undergoing thrombolysis and > 75 yrs
What is the goal of Primary PCI in management of STEMI?
Goal < 90 min if available
What is the secondary prevention of the management of STEMI?
Dual antiplatelet therapy (aspirin + clopidogrel) Beta-blockers ACE inhibitors Statins Control risk factors
What advice would you give to someone who has had a STEMI?
No driving for 1 month following MI
When is CABG considered?
In patients with left main stem or three-vessel disease
What are the early complications of Ischaemic Heart Disease (within 24-72 hrs)?
Death Cardiogenic Shock Heart Failure Ventricular Arrhythmias Heart Block Pericarditis Myocardial rupture Thromboembolism
What are the late complications of ischaemic heart disease?
Ventricular Wall Rupture Valvular Regurgitation Ventricular Aneurysms Tamponade Dressler's Syndrome Thromboembolism
What is the mnemonic for complications of MI?
DARTHVADE Death Arrhythmias Rupture Tamponade Heart Failure Valve disease Aneurysm Dressler's Syndrome Embolism
What are the two types of ways you can do to summarise the prognosis for patients with ischaemic heart disease?
TIMI Score
Killip classification
What are TIMI scores?
TIMI score (0-7) can be used for risk stratification Note: TIMI = thrombolysis in MI High scores are associated with high risk of cardiac events within 30 days of MI
What are the Killip classification?
Class I: no evidence of heart failure
Class II: mild to moderate heart failure
Class III: over pulmonary oedema
Class IV: cardiogenic shock
