ABC Medical Notes.com

Related Subjects: |Atherosclerosis |Ischaemic heart disease |Assessing Chest Pain |ACS: general |ACS: NSTEMI |ACS: STEMI |Hypertension |Acute Heart Failure |Chronic Heart Failure |Cardiac Thrombolysis

In practice however 99% of coronary artery narrowing is due to atherosclerotic disease of the coronary vessels and that is what we shall focus on.  Ischaemic heart disease is synonymous with the process of atherosclerosis.

About: Ischaemic myocardium can be due to

• Coronary artery narrowing
  • Atherosclerosis - obstructive plaques, or complicated plaques with thrombosis
  • Coronary artery spasm 
  • Vasculitis
• High wall stress impeding flow
  • Severe aortic stenosis also cause angina
  • Hypertrophic cardiomyopathy

Atherosclerosis:pathophysiology

• The first sign is the "fatty streak" which lies just below the endothelium which can even be seen in some children and young adults.
• This fatty streak  can progress to an atheromatous plaque containing cholesterol and cholesterol esters, necrotic debris, foam cells
• As it progresses the plaque can gradually obstruct the lumen and can ulceration with overlying thrombosis formation. The plaque fibrous cap can rupture releasing thrombogenic debris causing localised thrombosis in situ which can embolise downstream or occlude the local lumen.
• Be aware of the concept of the stable and unstable plaque. An unstable plaque is one that for one reason or other is more likely to become a complicated plaque with superficial ulceration or rupture.
• This can lead to total or subtotal coronary occlusion and myocardial infarction/angina/sudden cardiac death
• This process is seen in medium sized arteries and similar processes can be found in internal carotid arteries, renal vessels and such. Fatty plaques can be found in the aorta as well as vessels to the lower limbs.

Risk factors

• Age
• Male (premenopausal women protected until menopause)
• Smoking - direct correlation
• Hypertension - relates to systolic and diastolic pressures
• Family history (1st degree relative with MI/Angina aged under 50)
• Diabetes
• Dyslipidaemia - correlates LDL-Choleseterol and total cholesterol. Inversely related to HDL
• High fibrinogen
• Physical inactivity
• Alcohol - "J" shaped curve. Low dose good, then harmful in increasing amounts
• Obesity 

Clinical manifestations of IHD can be summarised as

• Asymptomatic eg found at PM, death from other cause
• Stable angina
• Unstable angina
• Non ST elevation MI
• ST elevation MI
• Arrhythmia
• Sudden cardiac death
• Ischaemic cardiomyopathy