2: Lecture 3

Question 1

What is the acute phase of heart failure?

Answer 1

Pulmonary embolism

Question 2

First cause of congestive heart failure?

Answer 2

Left ventricular dysfunction
Failure of left ventricle impedes delivery of oxygen to the whole body

Question 3

How to treat Left ventricular dysfunction

Answer 3

With positive ionotropic agents that increase contraction ability of heart to reestablish circulation

Question 4

Second cause of congestive heart failure

Answer 4

Neuroendocrine activation involving the renin-angiotensin-aldosterone system
Can lead to pathological hypertrophy of heart (increase in size) with decrease in contractility and reduction of stroke volume (extra tissue is not cardiac muscle)
(physically hypertrophy is when extra tissue is heart muscle as seen in pregnant women and athletes)

Question 5

What is systolic heart failure

Answer 5

When left ventricle (or sometimes right) cannot contract properly to eject blood due to weakened muscle
This causes a decrease in stroke volume
Occurs in patients after heart attacks

Question 6

What is an ejection fraction

Answer 6

Measure of how much blood leaves the heart during contraction
Low in systolic heart failure
Used for diagnosis of heart failure (under 40%, 50-70% is healthy)

Question 7

What is diastolic heart failure

Answer 7

A deficit in the filling capacity of the heart (resulting in less blood being ejected with each contraction)
Can have normal ejection fraction
Has reduced preload–>less distension on ventricle walls–>lower diastolic volume–>lower stroke volume

Question 8

Main cause of diastolic heart failure

Answer 8

Narrowing of the ventricle lumen
Can occur from long-standing hypertension causing cardiac hypertrophy and a reduction in ventricular volume (smaller ventricle lumen)

Question 9

Frank Starling Law

Answer 9

Healthy: small increase in preload–>large increase in stroke volume
Cardiovascular disease: increase in preload–>small increase in stroke volume
Heart attack: any size preload–>very low stroke volume

Question 10

Factors that contribute to heart failure

Answer 10

Uncontrolled hypertension
Diabetes
Myocardial infarction (damage to heart muscle from scar tissue formation)
Valve dysfunction (heart valves don’t close properly causing backflow that inhibits heart contraction)
Viral myocarditis (infection of heart tissue)

Question 11

Primary effects of Heart failure

Answer 11

Reduced cardiac output (to compensate for increase blood pressure/hypertension)
Compensation is by an increase sympathetic drive and salt and water retention
Problematic as eventually increases systolic and diastolic blood pressure (makes heart tire more easily)

Question 12

Long term effects of heart failure

Answer 12

Remodeling of the heart (to compensate for heart’s inability to pump blood)–>pathological hypertrophy

Question 13

Effects of Pathological hypertrophy

Answer 13

Leads to apoptosis of the cardiomyocytes and decrease in the number of cardiac muscle cells (forming a positive feedback loop)

Question 14

What is cardiac Preload

Answer 14

Pressure in the atrium determined by amount of blood entering
Increased in heart failure and treated with salt reduction and diuretics

Question 15

What is cardiac Afterload

Answer 15

Vascular resistance
Afterload is increased due to reflex sympathetic outflow and renin-angiotensin system
Increased afterload may reduce cardiac output

Question 16

Treatment for decrease on contractility of heart (during heart failure)

Answer 16

Ionotropic drugs will work directly on heart to increase contractility to restore pump performance

Question 17

Why does Heart rate increase during heart failure

Answer 17

sympathetic nervous system compensation to restore systemic blood flow

Question 18

How does body detect reduced cardiac output

Answer 18

Through reduction in carotid sinus firing (baroreceptors) and reduction in renal blood flow

Question 19

Response to decrease in baroreceptor signaling

Answer 19

Increase in sympathetic discharge from hypothalamus
Increase in force of contraction, heart rate, preload, and afterload

Question 20

Response to decrease blood perfusion of the kidneys

Answer 20

Increase in angiotensin II release
Increase preload and afterload on heart, also lead to hypertrophy

Question 21

Main action of positive ionotropic drugs

Answer 21

Work directly on muscle to increase force of contraction

Question 22

Main action of ACE inhibitors

Answer 22

Reduce action of angiotensin II

Question 23

Main action of Diuretics

Answer 23

Reduce the preload and afterload by reducing blood volume

Question 24

Main action of Vasodilators

Answer 24

Reduce Preload and afterload by reducing arterial resistance