8. IHD - diagnosis and treatment Flashcards
Name 5 tests that could be used to diagnose stable angina.
- exercise (treadmill/bicycle) ECG
- dobutamine stress ECG
- stress myocardial perfusion scan (measure radionuclide absorption)
- pharmacological cardiac MRI stress test
- PET scan (unusual)
What are the clinical examination findings of IHDs?
Stable angina:
- often normal
Acute coronary syndromes:
- often normal
- +/- clinical signs secondary to complications of cardiac tissue necrosis (NSTEMI/STEMI), e.g. acute heart failure, heart murmur, etc.
What ECG findings suggest the occurence of an MI in the past?
pathological Q waves
Describe the ECG findings for stable angina.
- Normal at rest.
- May show signs of previous MI (Q waves), atrial fibrillation or arrhythmias.
Describe the ECG findings for unstable angina.
- ST segment depression
2. T wave flattening/inversion
Describe the ECG findings for NSTEMI.
- ST segment depression
2. T wave flattening/inversion
Given that they have similar ECG findings, how can one differentiate between unstable angina and NSTEMI?
Troponin release unlikely in UA but occurs in NSTEMI due to myocyte necrosis.
Describe the ECG findings for STEMI.
- ST segment elevation
- T wave inversion
- Pathological Q wave
Which ECG leads would be affected by lateral myocardial damage?
I, aVL, V5 and V6
Which ECG leads would be affected by inferior myocardial damage?
II, III and aVF
Which ECG leads would be affected by anterior myocardial damage?
V3 and V4
Which ECG leads would be affected by septal myocardial damage?
V1 and V2
Which pharmacological treatments are recommended to treat stable and unstable angina? Explain why.
Improve blood flow:
- aspirin: anti-platelet
- statins: reduce cholesterol by inhibiting HMG-CoA reductase
Decrease BP:
- beta-blocker: reduces cardiac effort
- decreases HR (more time between each beat for coronary filling, reduces O2 demand)
- decreases BP
- ACE inhibitors: reduce BP (+ prognostic benefit in those with normal BP)
- oral nitrates/GTN spray:
- decrease BP (peripheral vasodilation)
- coronary artery vasodilation
- calcium channel blockers: decrease BP
Which revascularisation techniques are used to treat angina?
- Percutaneous Coronary Intervention (PCI)
2. Coronary Artery Bypass Grafting (CABG)
What is PCI?
- Non-surgical widening of the coronary artery.
- Blood stream accessed through femoral or radial artery… balloon catheter dilates the artery from within (coronary angioplasty)… metallic stent placed in artery after dilation.
