7. Ischaemic Heart Disease Flashcards
What increases the oxygen demand of the myocardium?
Rate
Contractability
Tension
What affects the oxygen supply to the myocardium?
Oxygenated blood
Coronary artery flow
What part of the heart is supplied by the left anterior descending artery?
Anterior wall of LV
Apex
Anterior 2/3 of the septum
What part of the heart is supplied by the right coronary artery?
Posterior wall
Name the forms of ischaemic heart disease
Angina
MI
Chronic ischaemic heart disease
What is stable angina?
Chest pain brought on by exercise and relieved by rest
75% occlusion of one of main coronary arteries
How is stable angina assessed?
Angiography
What conditions worsen stable angina?
Anaemia
Hypertrophy
What is unstable angina?
Stable angina that has recently progressed
The atherosclerotic plaque has been disrupted and caused a thrombus
High risk of acute MI
What are the causes of sudden cardiac death?
Thrombosis
Arrhythmia
Spasm in cocaine use
What is an MI?
Necrosis of the myocardium due to decreased blood supply
What is the clinical presentation of an MI?
Crushing central chest pain
Weakness, nausea, sweating, vomiting
What is the pathology of an MI?
Plaque rupture and thrombosis causes ischaemia
Begins subendocardium as that is furthest from blood supply
What is used to diagnose MI?
ECG
Troponin
Creatine kinase
What is troponin?
regulatory proteins of actin filaments in cardiac muscle
Released in any damage to heart, chemo, renal disease
How long does it take for changes to be seen in the myocardium after an infarction?
10 hours
What changes are seen in the myocardium after 1 day?
Coagulation necrosis
Hypereosinophila and wavy fibres (due to oedema)
Macroscopically heart is dark, red and firm
What happens to the myocardium 2-7 days after an MI?
Signs of inflammation in nearby tissue: neutrophils and oedema
Patient might have high WCC and fever
Macroscopically tissue is soft and yellow
What happens to the myocardium on days 7-14?
Dead tissue is resorbed and granulation tissue at edges
Macroscopically depressed area with red edges
What happens to the myocardium on weeks 2-8?
Fibrosis and increased vascularity
Macroscopically tissue is grey/white
How does the myocardium appear 8 weeks after an MI?
Dense fibrosis
Macroscopically a depressed thinned myocardium with a scar
What are rare causes of coronary artery occlusion?
Vasculitis
Thrombus due to hypercoaguability
Trauma causing coronary dissection
Vasospasm
What are the causes of sudden death in MI?
Ventricular fibrillation (especially with posterior inferior MI) Cardiac tamponade
What complications are associated with MI?
Arrhythmias within 48 hours LV failure and pulmonary oedema Cardiogenic shock Ventricular rupture and haemopericardium Chordae tendinae or papillary muscle rupture LV aneurysm formation Pericarditis and Dressler's syndrome
What finding would be present in LV aneurysm formation?
2 apex beats
What results from rupture through the ventricular wall post MI?
Haemopericardium and cardiac tamponade
What results from rupture through the septum post MI?
Ventricular septal defect
What results from rupture of the papillary muscle post MI?
Valve dysfunction and valve failure
What are the signs of mild LV failure?
Sinus tachycardia
What are the signs of moderate LV failure?
Dyspnoea and evidence of pulmonary oedema
What are the signs of severe LV failure?
Cardiogenic shock
Hypotension
Poor tissue perfusion
Reduced ejection fraction on ECHO
What type of MI is associated with pump problems?
Anterior MI
What type of MI is associated with conduction problems?
Posterior MI
What conditions are under the term chronic ischaemic heart disease?
Angina and progressive heart failure
What can be seen in chronic ischaemic heart disease?
Hypertrophy
Dilation
Narrow CA
Myocardial fibrosis
What drug is used for the primary prevention of chronic ischaemic heart disease?
Statins
What interventions are used to treat a STEMI?
Percutaenous coronary intervention
Thrombolysis
