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Normal heart Weight? Avg. Thickness Ventricular free wall?
- Male: 300-350 g
- Female: 250-300 g
- Left: 1.3-1.5 cm
- Right: .3-.5 cm
What's the most vulnerable part of the heart?
Subendocardium b/c its the most distal myocardium, most vulnerable to ischemia and least well perfused area.
What are the different types of arrhythmias?
- tachycardia - increased HR
- brachycardia- decreased HR
- both decrease cardiac output over time
futter or fibrillation- extremely rapid rates, chambers don't fully fill, also decreases cardiac output
What is the most common cardiac pathology and what are the causes?
Cardiac Hypertrophy; due to increased work
- 1) elevated pressure
- -from systemic hypertension
- - or aortic valve stenosis
- 2) increased blood volume
- - valvular regurgitation
- - congenital effects from shunting blood
- 3) Exercise ( not detrimental)
- 4) slowly developing severe anemia
- 5) hyperthyroidism
- 6) post infarction
- 7) idiopathic
Describe cardiac myopathy
normal myocyte( 10-15 micronswide, 100 microns long) increase 25 or more micro
nuclei become large, hyperchromatic, rectangular "box-car" shape
Gross pathologic features in response to pressure overload?
increased heart weight and wall thickniss to cavity ratio
Gross pathological features in response to volume overload?
- increased hypertrophy with increased dilation
- wall thickness to cavity increase proportionate
What extracellular changes occur doe to cardiac hypertrophy?
Extracellular CT increases relative to myocytes
collagen type changes and there is decreased compliance
no change in capillary growth so there is impaired diffusing capacity and increased susceptibility to ischemia
Why is exercise induced hypertrophy not detrimental?
B/c there is an increase in ECM and microvessels with myocyte: its proportionate
Underlying causes and common etiologies of Congestive heart failure.
what's the morphological appearance?
- Underlying causes: systolic dysfunction- decrease myocardial contractility
- diastolic dysfunction- decrease ability myocardium to expand and allow adeq. filling
- common etiologies:
- 1) L. vent hypertrophy from pressure overload or volume overload
- 2) chronic ischemic heart disease
- 3) cardiomyopathies
- 4)constrictive pericarditis
big, dilated and floppy. increased weight, chamber dilation, wall thinning, myocyte hypertrophy
What organs are affected when the Left ventricle fails?
- 1) Lungs- increased pulmonary venous pressure leads to edema
- 2) Kidneys- decreased perfusion
- 3) Brain- cerebral hypoxia
What organs are affected when the Right Ventricle fails?
- 1) Liver- increased weight, nutmeg liver
- 2) Kidneys
- 3) Portal system- spleen-ascites
- 4) peripheral tissues- ankle edema
- 5) pleura/pericardium
- 6) brain-hypoxia
- 7) jugular venous distention
What are the patterns of ischemic heart disease?
- -Angina pectoris
- -sudden cardiac death
- -myocardial infarction
- -chronic ischemic heart disease
What is Angina pectoralis and what is it related to?
Paroxysmal episodic pain- radiating, transient, induced by exertion
coronary atherosclerosis, valvular dysfunction, arrhythmias that impair coronary perfusion
What is unstable angina and what causes is?
It is a variant of angina pectoralis, can occur at rest, increased frequency, prolonged and merging attacks
related to thrombus formation and transient ischemia. increase MI risk
What causes cardiac death?
It's collapse and death w/i 24 hrs, related to ischemia, arrhythmias, absence of clinical history of ischemic heart disease
What is myocardial infarction related to?
It's ischemic necrosis of myocardium with prolonged chest pain that can radiate
- due to sudden occlusion coronary art flow
- mismatch in myocardial oxygen demands and coronary diffusion
- myocyte necrosis
What is chronic ischemic heart disease and what is it related to?
gradual or episodic coronary insufficiency with development congestive heart failure, preceding or following MI
- chronic ischemia
- history angina/MI
MI. Whos at the highest risk and what are the precipitating factors?
Men peak 55-64, women 8th decade; the older women get the closer the ratio gets
- hemorrhage, rupture of plaque
- sudden increased myocardial oxygen demand
- tachycardia, or valve dysfunction
What are the two morphological categories of Myocardial Infarction?
- 1) Transmural infarction-most common
- entire wall necrosis, acute plaque disruption with thrombosis lead to occlusion of flow, sharply defined by distrib. affected vessel
- 2) Subendocardial infarction
- necrosis inner 1/2-1/3 vent wall, not defined by single vessel, diffuse reduction coronary flow by atherosclerosis affect multiple vessels, subendocardium suffers ischemic necrosis