Unit 3 Additional Readings

Question 1

CAD

Answer 1

accumulation of atherosclerosis plaques in coronary arteries leads to reduction in blood flow to myocardium
- changeable risk factors: smoking, high BP, diabetes, high cholesterol lvls, obesity, sedentary lifestyle
- unchangeable risk factors: genetic, age, gender
- adult males more likely than adult females before 70 yrs old

Question 2

arrhythmia/dysrhythmia

Answer 2

abnormal rhythm as result of defect in conduction system of heart ⇒ heart beating irregularly, too quickly, or too slowly
- caused by factors that stimulate heart
- S&S: chest pain, SOB, lightheadedness, dizziness, fainting

Question 3

supraventricular/atrial arrhythmia

Answer 3

arrhythmia that begins in atria

Question 4

supraventricular tachycardia (SVT)

Answer 4

rapid but regular heart rate that originates in atria
- Tx: maneuvers that stimulate vagus (X) nerve and decrease heart rate, rubbing area over carotid artery in neck to stimulate carotid sinus, plunging face in cold water, antiarrhythmic drugs and destruction of abnormal pathway of radiofrequency ablation

Question 5

Ventricular arrhythmias

Answer 5

arrhythmias that originate in ventricles

Question 6

Heart block

Answer 6

arrhythmia that occurs when electrical pathways between atria and ventricles are blocked, slowing transmission of nerve impulses

Question 7

1st degree AV block

Answer 7

conduction through AV node is slower than normal
- P-Q interval prolonged

Question 8

2nd degree AV block

Answer 8

some of action potentials from SA node aren’t conducted through AV node
- Dropped beats because excitation doesn’t always reach ventricles

Question 9

3rd degree AV block

Answer 9

no SA node action potentials get through AV node
- autorhythmic fibers in atria and ventricles pace upper and lower chambers separately

Question 10

Complete AV block

Answer 10

ventricular contraction rate is <40 beats/min

Question 11

Atrial premature contraction (APC)

Answer 11

heartbeat that occurs earlier than expected and briefly interrupts normal heart rhythm
- Causes skipped heartbeat then forceful heartbeat

Question 12

Atrial flutter

Answer 12

contraction of atrial fibers is asynchronous so that atrial pumping stops altogether
- no clearly defined P waves
- irregularly spaced QRS complexes

Question 13

Ventricular premature contraction

Answer 13

when an ectopic focus, a region of heart other than conduction system, becomes more excitable than normal and causes occasional abnormal action potential to occur
- causes ventricular premature contraction/beat

Question 14

Ventricular tachycardia (VT or V-Tach)

Answer 14

arrhythmia that originates in ventricles and characterized by 4 or more ventricular premature contractions ⇒ ventricles to beat too fast

Question 15

Ventricular Fibrillation (VF or V-Fib)

Answer 15

contractions of ventricular fibers are completely asynchronous so that ventricles quiver rather than contract in coordinated way ⇒ ventricle pumping stops, blood ejection stops ⇒ circulatory failure and death
- No clearly defined P-waves, QRS complexes, or T-waves

Question 16

Myocardial Ischemia

Answer 16

reduced blood flow to myocardium

Question 17

Congestive Heart Failure

Answer 17

loss of pumping efficiency by heart
- As pump becomes less effective ⇒ more blood remain in ventricles at end of each cycle ⇒ end-diastolic volume (preload) increases ⇒ increased force of contraction and heart is overstretched ⇒ contracts less forcefully ⇒ potentially lethal positive feedback loop and low pumping capability

Question 18

Silent myocardial ischemia

Answer 18

ischemic episode without pain

Question 19

Myocardial infarction / heart attack

Answer 19

complete obstruction to blood flow in coronary artery

Question 20

Stenosis

Answer 20

narrowing of heart valve opening that restricts blood flow

Question 21

Mitral stenosis

Answer 21

scar formation or congenital defect causes narrowing of mitral/bicuspid valve

Question 22

Mitral insufficiency

Answer 22

backflow of blood from left ventricle into left atrium
- Caused by mitral/bicuspid valve prolapse (MVP): when one or both cusps of mitral/bicuspid valve protube into left atrium during ventricular contraction
– Most prevalent in women than men and doesn’t always pose serious threat

Question 23

Aortic stenosis

Answer 23

aortic valve is narrowed

Question 24

Aortic insufficiency

Answer 24

backflow of blood from aorta into left ventricle

Question 25

Rheumatic fever

Answer 25

acute systemic inflammatory disease that usually occurs after streptococcal infection of throat ⇒ bacteria triggers immune response where antibodies produced to destroy bacteria instead attack and inflame connective tissues in joints, heart valves, and other organs ⇒ weaken entire heart wall and damages mitral and aortic valves

Question 26

Regular moderate exercise

Answer 26

decreases incidence of heart attacks, reduce blood cholesterol, reduce severity of CAD, improve mood/quality of life

Question 27

Coronary collateral circulation

Answer 27

ability to supply areas of myocardium with blood through small new growth anastomoses (cross connection between adjacent fibers)
- Caused by hypoxia that occurs with CAD

Question 28

As adults age, their cardiovascular responses change

Answer 28

Decreases: maximal cardiac output, stroke volume, heart rate
Increases: maximal systolic blood pressure, diastolic blood pressure, mean arterial pressure

Question 29

Training intensity

Answer 29

most important factor in maintaining cardiovascular fitness

Question 30

Endurance training

Answer 30

increases blood volume, cardiac dimensions, mass, size of coronary vascular bed, internal diameter of coronary arteries
= arteries more distensible/stretch/expand during exercise