3-1: 8/29: Pathology Of Myocardial Adaptation, Aging, And Failure

Front 1

Do all myocardial adaptations results in structural changes?

What are examples non-pathological structural remodeling?

Back 1

No, some changes may merely be physiological, such as changes in rate, resistance, output

Normal structural changes = postnatal remodeling, adaptation to an exercise program

Front 2

What results in abnormally high preload?

Back 2

Preload = volume of blood in ventricle and wall stress during diastole

Anormal preload = volume overload due to valve incompetence or loss of contractility

Ventricle doesn't empty properly during systole or received blood from great artery during diastole

Front 3

What results in an abnormally high afterload?

Back 3

Pressure overload such as in systemic or pulmonary hypertension, valve stenosis, coarctation of aorta

Myocardium may be intact, but must adapt to meet prolonged increase in work demands

Front 4

What is myocardial hypertrophy an adaptation to?

Back 4

Response to increase in work

Results in increased size of myocytes and interstitial tissue

Not all bad, e.g., fitness programs

Note dilation occurs before hypertrophy

Front 5

What changes occur in myocardial hypertrophy?

Back 5

Increased myocyte diameter, length
Additional sarcomeres
Inc'd contractile proteins
Inc'd mitochondria (for ATP)
Inc'd collagen

Front 6

What are the mechanical and trophic triggers of myocardial hypertrophy?

Back 6

Mechanical: Stretching

Trophic:
IGF-1 (polypeptide GF)
Ag-II, Endothelin I, alpha agents (Vasoactive)

Front 7

What genes are induced in myocardial hypertrophy?

What do these genes allow for?

Back 7

c-fos
egr-1
c-jun

These are early genes that reactivate embryonal/fetal gene programming:
Expression of Atrial Natriuretic Factor (ANF)
Change from a-myosin heavy chain to b-myosin heavy chain (more energetically-economic contraction)

Front 8

What is cor pulmonale?

Causes?

Back 8

Hypertrophy of RV

Can be due to COPD, recurrent pulm emboli, MS (anything that increases Pulm Artery pressure)

Leads to tricuspid regurg

Front 9

When does heart failure occur?

Define:
Congestive Failure
Forward Failure

Back 9

Heart unable to maintain output sufficient for metabolic requirements

Congestive: congestion present in lungs

Forward: dec'd output

Backward: Inc'd EDP and inc'd venous pressure

Front 10

Heart Failure:
Systolic vs Diastolic Causes

Back 10

Systolic: loss of contractility

Diastolic: inadequate inflow into ventricle

Front 11

Effect of heart failure on:
beta-adrenergic receptor density
cAMP
endothelin-1

Back 11

ALL DECREASE

(these things tend to increase with hypertrophy)

Front 12

B-type Netriuretic Peptide (BNP):
Role
Diagnostic Use

Back 12

Peptides which regulate fluid homeostasis and vascular tone

Secreted by ventricular myocardium when volume expanded or pressure overloaded; it's a measure of myocardial stretching

Can be used to diagnose CHF!

Front 13

Signs of Left Heart Failure

Back 13

Left:
Pulm congestions, edema:
Congested capillaries, veins
Edema in septa and alveoli
Hemosiderin-laden macs (if long-term)

Renal effects:
Azotemia (not getting rid of waste products)
Tubular Necrosis
Renin Activation

Brain effects:
Hypoxic encephalopathy

Front 14

Signs of Right Heart Failure

Back 14

Congestion in systemic organs
Liver (hepatomegaly, nutmeg liver, centrilobular necrosis)
Splenomegaly
Edema
Effusions in pleural, peritoneal, and pericardial cavities

Front 15

Aging heart changes

Back 15

Formerly known as brown atrophy due to presence of LIPOFUSCIN

Bphil degeneration due to accumulation of glycogen metabolism byproducts

Hypertrophy due to inc'd wall stress from inc'd resistance (from arterial wall stiffness)

Inc in collagen

Fewer myocytes (due to apoptosis)

Amyloidosis (from tranthyretin): can be cardiac or systemic

LV cavity decreases in size, upper septum bulges into LV Outflow Tract

Calcification

Lambl's excrescences

Front 16

Eccentric Hypertrophy:
Causes

Back 16

Eccentric: RV and LV hypertrophy; causes: volume overload (mitral regurg)

Don't get LV dilation with mitral stenosis

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