MI Flashcards
MI Description, risk factors
- Prolonged ischaemia (>20min) causing irreversible damage to the heart muscle (necrosis & loss of contractility), usually due to thrombus
- Non-ST elevation (non-STEMI) or STEMI
- Starts as subendocardial, but can lead to transmural after 4-6h (full thickness)
Risk factors
* Elevated serum lipids
* HTN
* Smoking, drugs
* Obesity, metabolic disorder, obesity
MI signs and symptoms
Pain: immobilising chest pain, not relieved by nitrates, described as heavy, tighness, may radiate to neck, jaw, arm (this is different to women and DM)
Diaphoresis & cool skin: due to catecholamine release, SNS activation & peripheral vasocontriction
High HR & BP, BP eventually drops
jugular distension & abnormal heart sounds
N&V: reflex stimulation due to pain
Fever: due to systemic inflammation
MI Healing
- Leukocytes infiltrate area, neutro & macro remove necrosis, collagen matrix set down
- 10-14 days, scar tissue weak
- 6 weeks: scar completely replaced injured tissue, but is less compliant
- Ventricular remodelling, where muscle hypertrophy’s, to try to compensate (can lead to HF)
MI complications
- HF
- dysrhythmias
- Pericarditis
- Cardiogenic shock
- Ventricular aneurysm
MI diagnostic studies
- 12 lead ECG (change in QRS, ST, T wave - can distinguish STEMI from NSTEMI)
- Serum markers: troponin, creatin kinase -MG, myoglobin
- Coronary angiogram
- Exercise stress testing when ECG is non-diagnostic
MI Management
- continuous 12 lead ECG monitoring
- Upright with O2 > 93
- IV access
- Glyceral trinate and aspirin
- Pain relief (morphine)
- NSTEMI/-ve markers: antiplatelets, heparin, angiography
- STEMI/+ve markers: reperfusion with PCI and IV thrombolytic (reteplase) tx (confirm with ECG within 6h)
- Coronary artery bypass graft to revascularise coronary artery from aorta (when other options fail)
Medications
- IV glyceryl trinitrate: vasodilator for angina
- Morphine: chest pain, also a vasodilator
- BB: reduce HR, BP
- ACE inh: prevents remodelling & HF
- Antidysrythmias
- Statins
- Stool softeners for constipation
Nursing management
- Monitoring of ECG, vitals, FB, heart sounds
- Manage pain, rest, behaviour & emotion
- Given O2, nitrates and analgesics
For CABG or PCI
* assess for bleeding at catheter signs, wound care
* Frequent assessments of vitals
* Fluid status and electrolytes
* DVT prevention
* Continuous ECG
- Ecourage exercise, educate patient (heart problems, risk factors and signs, medications)
