Lecture 15: Cardiac failure heart sounds and shock

Question 1

Cardiac failure definition

Answer 1

Failure of the heart to pump enough blood to satisfy the needs of the body

Question 2

Effects of sympathetic innervation in cardiac failure

Answer 2

Strengthens muscle contraction
Increases tone of most vessels, especially veins
Increases mean systemic filling pressure

Question 3

Compensatory mechanism by ANS for acute cardiac failure

Answer 3

Baroreceptor reflex
Chemoreceptor reflex
CNS ischemic response

Question 4

Acute effects of heart attack

Answer 4

Reduced cardiac output

Damming of blood in veins–> increased venous pressure

Question 5

Effect of increased right atrial pressure during heart attack

Answer 5

Increased right atrial pressure can maintain cardiac output at near normal levels despite a weak heart

Question 6

Exercising while in compensated heart failure

Answer 6

Causes immediate return of symptoms to acute heart failure

Question 7

What happens to capillary pressure during heart failure and what are the results

Answer 7

Capillary pressure decreases which reduces chances of peripheral edema

Question 8

What causes pulmonary edema

Answer 8

Left side of heart fails without failure of right side
Blood is pumped into lungs but not out of lungs
Pulmonary filling pressure rises, capillary pressure rises
Blood can then flow out of capillaries into lungs causing edema

Question 9

Two major problems of left heart failure

Answer 9

Pulmonary vascular congestion

Pulmonary edema

Question 10

Changes in aortic, capillary and right atrial pressure during heart failure

Answer 10

Aortic pressure drops
Capillary pressure drops
Right atrial pressure increases

Question 11

Atriovenous fistula

Answer 11

Overloads heart because of excessive venous return caused by decrease in peripheral vascular resistance
Venous return curve rotates upward

Question 12

Beriberi

Answer 12

Thiamin deficiency
Weakening of heart
Decreased blood flow to kidney-->fluid retention
Increased mean filling pressure
Shift of venous return curve to right

Question 13

First heart sound

Answer 13

AV valves close at the onset of ventricular systole

Question 14

Second heart sound

Answer 14

Semilunar valves close at end of systole

Question 15

Left to right shunt and example of condition

Answer 15

Blood flows backward and fails to flow through systemic circulation
Patent ductus arteriosus

Question 16

Right to left shunt

Answer 16

Blood flows from right to left side of heart, bypassing lungs
Tetralogy of fallot

Question 17

Circulatory shock definition

Answer 17

Inadequate blood flow throughout the body to the extent that tissues are damaged because of low oxygen/nutrients

Question 18

Cardiac abnormalities that decrease ability to pump blood

Answer 18

Myocardial infarction
Toxic state of heart
Severe valve dysfunction
Heart arrhythmias

Question 19

Cardiogenic shock is

Answer 19

Circulatory shock resulting from diminished cardiac pumping ability

Question 20

Factors that decrease venous return

Answer 20

Diminished blood volume
Decreased vascular tone
Obstruction of blood flow

Question 21

Negative feedback mechanisms during cardiac shock

Answer 21

Powerful sympathetic reflux initiated by arterial baroreceptors and vascular stretch receptors
-Results from decrease in arterial pressure after hemorrhage and decrease in pressures in pulmonary arteries and veins

Question 22

Sympathetic reflexes in cardiac shock result in

Answer 22

Arterioles constrict in most of circulatory system
Veins and venous reservoirs constrict
Heart activity increases markedly

Question 23

Autoregulation in cerebral and cardiac vessels

Answer 23

Maintain more or less normal pressure as long as the arterial pressure does not drop below 70mm Hg

Question 24

Baroreceptor reflexes

Answer 24

Elicit powerful sympathetic stimulation of circulation

Question 25

Central nervous system ischemic response

Answer 25

Elicits even more powerful sympathetic stimulation throughout body but is not activated until arterial pressure drops below 50mm Hg

Question 26

Reverse stress relaxation of the circulatory system

Answer 26

Causes blood vessels to contract around the diminished blood volume so that the blood volume that is available more adequately fills the circulation

Question 27

Increased secretion of renin by the kidneys and formation of angiotensin II

Answer 27

Constricts the peripheral arteries and also causes decreased outputs of water and salt by the kidneys

Question 28

Increased secretion by the posterior pituitary gland of vasopressin (ADH)

Answer 28

Constricts peripheral arteries and veins and greatly increases water retention by kidneys

Question 29

Increased secretion of epinephrine/norepinephrine by adrenal meddula

Answer 29

Constricts peripheral arteries/veins and increases heart rate

Question 30

Compensatory mechanisms that return blood volume back to normal

Answer 30

Absorption of large quantities of fluid from intestinal tract Absorption of fluid into the capillaries from interstitial spaces of body Conservation of water/salt by kidneys Increased thirst and appetite for salt

Question 31

Factors in the final lethal progression of shock

Answer 31

``` Vasomotor failure Blockage of small vessels Increased vascular permeability Release of toxins by necrotic tissue Cardiac depression caused by endotoxin Generalized cellular deterioration ```

Question 32

Neurogenic shock

Answer 32

Shock may occur without loss of blood volume | Vascular capacity increases so much that normal amount of blood cannot fill space

Question 33

Causes of neurogenic shock

Answer 33

Sudden loss of vasomotor tone-dilation of veins Deep general anesthesia Spinal anesthesia Brain damage