Week 3- cardiac Flashcards
(23 cards)
AMI pathophysiology
Atherosclerosis
- Is a progressive disease process that leads to thickening and hardening of the arterial wall due to accumulation of lipid laden macrophages leading to development of plaque
- Due to an inflammatory process
- Both innate and adaptive immune response involved
- It is the major cause of coronary artery disease
- It is the most common cause of AMI
The non modifiable risk factors for atherosclerosis (and thus potential risk factors for an AMI) are
Advanced Age
Men > 45
Women > 55 (or early menopause)
Male gender (until age 60)
Indigenous race
Genetic predisposition
Diabetes mellitus
Modifiable risk factors for atherosclerosis (and thus potential risk factors for an AMI) are
Smoking
Obesity and physical inactivity
Oral contraceptives- especially in women who also smoke
Hyperlipidaemia
Hypertension
Diabetes
Psychosocial factors (e.g. stress)
Heavy alcohol consumption
Patient Assessment AMI- Danger, Response, Send for Help
It is anticipated that there are no abnormal findings for Danger or Response, send for help if there are
Patient Assessment AMI and management- Airway
It is anticipated that there are no abnormal findings for Airway.
- If GCS < 9 then urgent help is required
- Consider suction, airway adjuncts, head tilt, jaw thrust, chin lift
Patient Assessment AMI and management- Breathing
- Patient may have an increased RR or WOB
- May have crackles on chest auscultation
- Patient may have SpO2 < 93%
- If patient has SpO2 <93% apply oxygen
- Ensure patient is sitting up in bed
- If crackles are auscultated GTN may be required if not hypotensive
- CXR will be required
Patient Assessment AMI and management- Circulation
- May have increased HR
- May have increased BP or decreased BP
- Likely to have chest pain
- May have pale skin colour, may be diaphoretic or clammy, and cool
- Urgent ECG is required – confirm if STEMI
- Aspirin 300mg
- Analgesia is required – morphine, fentanyl
- GTN may be indicated
- IVC is required and if STEMI then a second IVC
- Biomarkers – Troponin, CK
- Pathology – FBE, U&E, Lipid levels, Glucose, Clotting, X Match
- If hypotensive may require inotropic support or cautious use of IV fluids
Patient Assessment AMI- Disability
- May be agitated
- May be confused
- May be light-headed
- May have altered BSL
Electrocardiograph (ECG)
ECG Changes can:
* Demonstrate if the patient is experiencing a STEMI or Non STEMI
* Determine which surface of the heart is affected
* Indicate which coronary artery is involved
* Guide nursing and medical management
ECG is the sole test require to select patients for emergency reperfusion
* ST elevation in > 2 contiguous leads of
* >2mm in precordial leads
* > 1mm in limb leads
* A diagnosis is confirmed with an ECG, PHx, Physical exam and enzymes/markers
Percutaneous Coronary Intervention (PCI) vs Thrombolysis
- PCI is recognised as the gold standard treatment for STEMI
- The acceptable delay to PCI will vary with time from symptom onset to presentation
o 90 minutes within first medical
contact
o If patient presents within 12
hours of symptom onset
o If rescue PCI is needed - Thrombolysis should be considered early if PCI not available
- Streptokinase, Alteplase (rt-PA), Reteplase (r-PA), Tenecteplase (TNK)
Preparing a patient for PCI
- Thorough medical history
- U&E, eGFR, FBE, clotting, X-match. Loading doses of Aspirin and antiplatelet (Clopidogrel or Ticagrelor)
- Heparin bolus dose
- Right wrist and right groin should be shaved.
- Consent
- List of current medications
- Baseline 12 lead ECG
- Hands free defibrillator pads should be applied to the STEMI patient
Absolute Contraindications for Thrombolysis- Risk of bleeding
- Active bleeding
- Suspected aortic dissection (including new neurological symptoms)
- Significant closed head or facial trauma within 3 months
- Intracranial or intra-spinal surgery within 2 months
Absolute Contraindications for Thrombolysis- Risk of intracranial haemorrhage
- Any prior intracranial haemorrhage
- Known structural cerebral vascular lesion (e.g. AV malformation)
- Known malignant intracranial neoplasm (primary or metastatic)
- Ischemic stroke within 3 months
- Severe uncontrolled hypertension that is not responsive to emergency management
Relative Contraindications for Thrombolysis- Risk of bleeding
- Active Gastrointestinal bleed, or recent (within 4 weeks) internal bleeding
- Current use of anticoagulants: the higher the international normalised ratio (INR), the higher the risk of bleeding
- Non-compressible vascular punctures
- Recent major surgery (< 3 weeks)
- Traumatic or prolonged (> 10 minutes) cardiopulmonary resuscitation
- Pregnancy
Relative Contraindications for Thrombolysis- Risk of intracranial haemorrhage
- History of chronic, severe, poorly controlled hypertension
- Severe uncontrolled hypertension on presentation (> 180 mmHg systolic or > 110 mmHg diastolic)
- Ischaemic stroke more than 3 months ago,
- Dementia
- Known intracranial abnormality not covered in contraindications
Cardiac Pacemakers
A cardiac pacemaker is a device that sends electrical impulses to the myocardium to initiate a mechanical contraction.
Indications for Pacemaker
- Acquired atrioventricular blocks in adults
o e.g. 2nd & 3rd degree heart Block (2nd and 3rd degree AVB). - Sinus node dysfunction eg. sick sinus syndrome.
- Prevention and termination of tachyarrhythmias.
- Heart failure and dilated cardiomyopathy
- Bradyarrhythmias
- Post cardiac surgery
- Short term treatment of transient conditions
- Long term treatment of chronic conditions
Types of Pacemaker: Temporary
- Temporary pacing is where the energy source is outside the body
- There are several types:
- External/ Transcutaneous
- Endocardial/ Transvenous
- Epicardial/ Transthoracic (used post cardiac surgery)
Types of Pacemaker: Temporary- External/Transcutaneous
- Pads (electrodes) are placed on the chest wall
- This type of pacing requires more energy
- It may be painful for the patient
- We do this in an emergency where there isn’t time to insert a transvenous wire
Types of Pacemaker: Temporary- Endocardial/Transvenous
- Pacing wire is inserted in the vena cava through the right atria into the right ventricle and is attached to an external pulse generator
Types of Pacemakers: Permanent
Single Chamber Pacemaker
* The ventricle (right) is paced
Dual Chamber Pacemaker
* The ventricle (right) is paced
* The atrium (right) is paced
Permanent Pacemaker Potential Complications
- Recovery is usually uncomplicated
- Reduction in activities that involve arm movement for first few weeks
- Potential for lead dislodgement or breakage
- Potential for pneumothorax during procedure
- Common post procedure complications – infection and bleeding
- Flat batteries
- Electromagnetic interference – patients with pacemakers can Not have an MRI
