- ACUTE CORONARY SYNDROMES - Flashcards
Define Coronary Artery Disease (CAD)
An impedance or blockage of on or more arteries that supply blood to the heart, usually due to atherosclerosis
Outline the pathophysiology of CAD
- Endothelial dysfunction results in increased permeability, allowing excess LDL to accumulate in the intima, a chemical reaction occurs in the intima making them oxidised LDL
- Stimulation of the endothelial cells from reaction results in diffusion of lipids and inflammatory cells (monocytes and T lymphocytes) into endothelial cells and subendothelial spaces
- Monocytes and macrophages produce inflammatory mediators
- Macrophages ingest O-LDLs and become fat lade and frothy; these are called foam cells
- Foam cells form fatty streaks and promote the migration of smooth muscle cells from the tunica media to the tunica intima and this causes smooth muscle cell proliferation
- Increased SMC proliferation results in increased synthesis of collagen, which hardens plaque and forms a fibrous cap over lipid core, protruding into lumen
- Foam cells die and release lipid contents resulting in the formation of plaque
- With increased turbulance around protruding plaque, from HTN or increased cardiac workload, the plaque may rupture, releasing its contents.
- The clotting process is initiated to contain lipid contents
- Thrombus is formed and platelets adhere to the thrombus
- Thrombus then inhibits blood flow/ O2 supply to the heart
- ishccaemia/infarct
Discuss the pharmacological management of patients with chest pain
- Aspirin (antiplatelet to reduce platelet aggregation and thrombus formation)
- GTN (vascular smooth muscle relaxant - reduces preload and afterload and thus reduces O2 demmand)
- Morphine ( reduces SNS stimulation resulting in a decrease in catecholamine realease and thus reduces O2 demmand. Also works as a vasodilator)
Discuss the pathophysiology of a STEMI
ACS pathophysiology +:
- thrombus fully occludes the vessel and involves the full thickness of the ventricular wall
- results in an imbalance between O2 supply and demmand to the myocardial cells
- ischaemia
- cell injury/death
Discuss the management of a STEMI
- Code STEMI
- Drugs (Aspirin, anti-platelet, heparin)
- PCI (percutaneous coronary intervention - cath lab) <60 mins
- Throbolysis should be considered if PCI unavailable
- CABGS
Describe how to differentiate between cardiac pain and non-cardiac pain
- nature
- location
- radiation
- precipitating/relieving factors
- Assoc clinical manifestations
Describe conditions that cause ischaemic cardiac chest pain and non-ischaemic cardiac chest pain
Ischaemic cardiac chest pain (angina)
- CAD (atherosclerosis)
- blood clots
- coronary artery spasm
- trauma
- MI
Non-Ischaemic cardiac chest pain
- pericarditis
- myocarditis
- dissecting aortic aneurysm
- atypical ballooning syndrome (takotsudo cardimyopathy)
Outline patient selection criteria for reperfusion therapy
Is the PCI delay time <90mins?
- door to needle (D2N)
- door to balloon (D2B)
- PCI delay = D2B - D2N
List absolute contraindications to thrombolytic therapy
- ischaemic CVA within 3 months
- Intracranial CA
- Aortic dissection
- active bleeding
- head trauma < 3 months ago
Outline four (4) clinical signs which may indicate that reperfusion has been successful
. - ST segment recovery
- QRS vector changes
- re-perfusion arrhythmias
- T wave configuration changes
Briefly outline nursing priorities for a patient undergoing reperfusion therapy
- swift assessment for reperfusion contraindications
- pt education (risk of bleeding, having to stay still)
- swift preparation of pt (large bore IVs, ECG, pedal pulses, checklist)
List the complications that may occur post AMI
- Ischaemic complications (reperfusion failure, angina, infarction, infarction extension)
- Mechanical complications (cardiogenic shock, MV dysfunction, cardiac rupture)
- Throbosis and embolic complications (CNS or peripheral embolisation)
- Chronic complications (pericarditis, depression)
State the clinical indications for recording a right and posterior ECG
Right sided ECG:
- in the case of an inferior AMI (STE in II,III,aVF)
Posterior ECG
- STD in V1-3
Specify where you will place the V leads to record a right and posterior ECG
Right:
V1-6 are placed in a mirror image fashion from standard precordial leads
Posterior:
V4-6 are moved to the posterior of the L chest in lead V7-9 positions
Describe the clinical implications of a pathological Q wave
Pathological Q waves may indicate:
- MI
- Cardiomyopathies
- Rotation of the heart
- Incorrect lead placement
Define unstable angina
- occuring at random and at rest
- no particular pattern
- lasts longer than 20 mins
Describe the desired action of Aspirin in the acute coronary syndrome (ACS) patient
- antiplatelet to reduce platelet aggregation and thrombus formation
List anti-platelet therapies, other than Aspirin, that are available in your ED and describe their mode of action
- clopidogrel
Discuss the action of nitrates in the ACS patient
- vascular smooth muscle relaxant - reduces preload and afterload and thus reduces O2 demmand
Explain the action of beta-blockers in the ACS patient
- Inhibit chronic activation of neuro-hormonal system
- Positive ionotropic and chronotropic responses
- Allow for renal and systemic vasodilation
Identify the thrombolytic agents are available in your ED and explain their specific mode of action for each
- Alterplase
- Reteplase
- Tenecteplase
Outline the nursing management of the patient receiving thrombolysis
- Identify and contraindications
- Educate pt on risk of bleeding
- Set up of infusion
- Assess vital signs frequently
- continuous cardiac monitoring
- evaluate response to therapy
- bed rest for 6 hrs
- monitor body fluid and assess for any signs of haemorrhage
- monitor for early signs of re-occlusion
Identify the modifiable for CAD
- cigarette smoking
- obesity
- hypertension
- physical inactivity
- kidney disease
- diabetes mellitus
- alcohol consumption
- stress
- elevated LDL
- reduced HDL
Identify the non-modifiable for CAD
- males >45 years
- females >55 years
- PHx of CAD
Discuss the pathophysiology of an NSTEMI
ACS pathophysiology +:
- formation of a non - occlusive thrombus which limits myocardial perfusion
Discuss the diagnostic criteria of a STEMI
- ACS with ECG changes
- ST elevation >2mm in 2 or more precordial chest leads
- ST elevation >1mm in 2 or more limb leads
- new LBBB pattern
Discuss the diagnostic criteria of an NSTEMI
- Typical/atypical CP, age risk factors, ECG changes
- abnormal, dynamic ST segment deviation >0.5mm or new T wave inversion >2mm
- ECG may be normal, changes in only 50% of cases
- ACS without ECG changes but with a rise in troponin
Discuss the management of an NSTEMI
- Aspirin
- Risk stratification (high, intermediate, low)
High - antiplatelet, PCI and re-vascularisation
Intermediate - Observe with frequent ECGs, repeat troponin, provocative testing to promote re-classification
Low - assessed and d/c on increase blood thinners and early OP cardiologist r/v
List relative contraindications to thrombolytic therapy
- HTN >180/110
- ischaemic CVA > 3 months ago
- dementia
- intracranial disease
- traumatic or prolonged CPR
- major symptoms in the past 3 weeks
- internal bleeding past 2-4 weeks
- non-compressible vascular punctures
- pregnancy
- current anticoagulation therapy
