Lecture 8 8/29/24

Question 1

What is heart failure?

Answer 1

clinical syndrome in which impaired emptying or filling of the heart causes clinical signs of exercise intolerance and/or congestion

Question 2

What happens when cardiac performance declines?

Answer 2

compensatory mechanisms are activated in order to preserve perfusion pressure and cardiac output

Question 3

What are the priorities of the cardiovascular system that are preserved in the event of cardiac performance decline?

Answer 3

–systemic arterial pressure
-cardiac output
-venous pressures

Question 4

What are the results of the cardiovascular compensatory mechanisms?

Answer 4

-vasoconstriction
-increases in inotropic state
-retention of salt and water

Question 5

How does vasoconstriction help to preserve blood pressure?

Answer 5

BP = CO x VR; therefore, when cardiac output falls, a rise in vascular resistance can maintain blood pressure

Question 6

What is eccentric hypertrophy?

Answer 6

-response to volume overload
-hypertrophy and lumen dilation
-wall thickness is normal compared to lumen size

Question 7

What is concentric hypertrophy?

Answer 7

-response to pressure overload
-hypertrophy without lumen dilation
-wall thickness is increased compared to lumen size

Question 8

What is the Frank-Starling Law of the Heart?

Answer 8

kidneys retain salt and water as a compensatory mechanism

Question 9

What are the peripheral compensatory mechanisms during heart failure?

Answer 9

-activation of adrenergic nervous system
-activation of renin-angiotensin-aldosterone system
-other endocrine products

Question 10

What are the functions of angiotensin II?

Answer 10

-vasoconstriction
-modulation of ANS/increase in sympathetic tone
-dypsogen release/increase in thirst
-stimulation of aldosterone release
-stimulation of ADH release

Question 11

Why is CHF considered to have unstoppable progression?

Answer 11

activation of the compensatory mechanisms is only favorable in the short term; long term, activation of ANS and RAAS has detrimental effects

Question 12

What do the physical findings in an animal with stage C heart failure typically reflect?

Answer 12

-causative disease
-consequences of congestion
-sympathetic activation

Question 13

How does respiratory sinus arrhythmia relate to CHF?

Answer 13

the presence of RSA is virtually incompatible with a diagnosis of CHF

Question 14

What are the main strategies of heart failure therapy?

Answer 14

-manipulation of the four main determinants of cardiac output
-treatment of neuroendocrine abnormalities

Question 15

How can preload be reduced?

Answer 15

-diuretics; i.e. furosemide
-venodilators, i.e. nitroglycerin

Question 16

What is important about preload reduction with diuretics such as furosemide?

Answer 16

progression of heart failure requires adjustments in the medication dosage

Question 17

What are the mechanisms behind diuretics decreasing preload?

Answer 17

-increased urine production, altering water balance and decreasing intravascular volume
-decrease in intravascular volume decreases venous pressures so the lymphatic system can clear excess tissue fluid

Question 18

What are the characteristics of furosemide?

Answer 18

-can be given PO, SQ, IM, or IV
-rapid onset of action when given IV
-generally administered every 12 hours when given orally as at-home therapy

Question 19

What are the adverse effects of furosemide?

Answer 19

-hypovolemia
-pre-renal azotemia
-electrolyte derangements