- caused by impaired blood flow to the myocardium
- usually caused by accumulation of atherosclerotic plaque
coronary artery disease (CAD)
what are the symptoms of CAD?
- may be asymptomatic
- may lead to angina pectoris, acute coronary syndrome, MI, heart attack, disrhythmias, heart failure, death
- chest pain resulting from reduced coronary blood flow
- causes temporary imbalance between myocardial blood supply and demand
angina pectoris
- condition of unstable cardiac ischemia
- includes unstable angina and acute myocardial ischemia (with or without injury to myocardial tissue)
acute coronary syndrome (ACS)
- necrosis (death) of myocardial cells
- life-threatening event
- occures when blood flow to a portion of the cardiac muscle is blocked
- if circulation is not restored loss of functional mocardium affects the heart’s ability to maintain an effective cardiac output
- may ultimately lead to shock and death
acute myocardial infarction (AMI)
what arteries supply blood, oxygen and nutrients to the myocardium?
the left and right main coronary arteries
where do the main coronary arteries originate?
in the root of the aorta, just outside the aortic valve
how is blood flow through the coronary arteries regulated?
- aortic pressure (primary regulator)
- heart rate
- metabolic activity of heart
- blood vessel tone
- collateral circulation
what is the most common cause of reduced blood flow?
atherosclerosis
- progressive disease characterized by atheroma (plaque) formation
- affects intimal and medial layers of large and midsized arteries
- precipitated by unknown factors
- lipoproteins and fibrous tissue accumulate in the arterial wall
atherosclerosis
- complex lesions consisting of lipids, fibrous tissue, collagen, calcium, cellular debris, capillaries
- can rupture or ulcerate»_space; thrombosis
atheromas
where does atherosclerosis tend to occur?
at bifurcations or branches of arteries
-results when the O2 supply is inadequate to meet metabolic demands
ischemia
what are the critical factors for coronary metabolic needs?
- coronary perfusion
- myocardial work load
what are the three categories of angina?
- stable
- unstable
- variant
-a dynamic state in which coronary blood flow is acutely reduced but not fully occluded
acute coronary syndrome
what are the precipitating events of acute coronary syndrome?
- rupture/erosion of atherosclerotic plaque
- coronary artery spasm
- progressive vessel obstruction
- inflammation of coronary artery
- increased myocardial oxygen demand
- decreased oxygen supply
- occurs when blood flow to a portion of cardiac muscle is completely blocked
- results in prolonged tissue ischemia and irreversible cell damage
acute myocardial infarction
what are some complications of acute myocardial infarction?
- dysrrythmias
- pump failure
- cardiogenic shock
- infarct extension
- structural defects
- pericarditis
-inflammation of the pericardial tissue surrounding the heart
pericarditis
what are the immediate treatment goals for an MI patient?
- relieve chest pain
- reduce the extent of myocardial damage
- maintain cardiovascular stability
- decrease cardiac workload
- prevent complications
what are some diagnostic tests for CAD?
- C-reactive protein
- ankle-brachial blood pressure index
- electron beam computer tomography
- myocardial perfusion imaging
- ECG
- echocardiogram
- radionuclide imagine
- hemodynamic monitoring
what are some diagnostic tests for CAD involving serum levels?
- creatinine kinase
- CK-MB
- troponins
- myoglobin
- CBC
- ABGs
- proteins released during MI that are sensitive indicators of myocardial damage
- normally not detected in the blood but released when cardiac muscle is necrotic
troponins
