Unit 3 Additional Readings Flashcards
CAD
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
arrhythmia/dysrhythmia
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
supraventricular/atrial arrhythmia
arrhythmia that begins in atria
supraventricular tachycardia (SVT)
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
Ventricular arrhythmias
arrhythmias that originate in ventricles
Heart block
arrhythmia that occurs when electrical pathways between atria and ventricles are blocked, slowing transmission of nerve impulses
1st degree AV block
conduction through AV node is slower than normal
- P-Q interval prolonged
2nd degree AV block
some of action potentials from SA node aren’t conducted through AV node
- Dropped beats because excitation doesn’t always reach ventricles
3rd degree AV block
no SA node action potentials get through AV node
- autorhythmic fibers in atria and ventricles pace upper and lower chambers separately
Complete AV block
ventricular contraction rate is <40 beats/min
Atrial premature contraction (APC)
heartbeat that occurs earlier than expected and briefly interrupts normal heart rhythm
- Causes skipped heartbeat then forceful heartbeat
Atrial flutter
contraction of atrial fibers is asynchronous so that atrial pumping stops altogether
- no clearly defined P waves
- irregularly spaced QRS complexes
Ventricular premature contraction
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
Ventricular tachycardia (VT or V-Tach)
arrhythmia that originates in ventricles and characterized by 4 or more ventricular premature contractions ⇒ ventricles to beat too fast
Ventricular Fibrillation (VF or V-Fib)
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
Myocardial Ischemia
reduced blood flow to myocardium
Congestive Heart Failure
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
Silent myocardial ischemia
ischemic episode without pain
Myocardial infarction / heart attack
complete obstruction to blood flow in coronary artery
Stenosis
narrowing of heart valve opening that restricts blood flow
Mitral stenosis
scar formation or congenital defect causes narrowing of mitral/bicuspid valve
Mitral insufficiency
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
Aortic stenosis
aortic valve is narrowed
Aortic insufficiency
backflow of blood from aorta into left ventricle
Rheumatic fever
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
Regular moderate exercise
decreases incidence of heart attacks, reduce blood cholesterol, reduce severity of CAD, improve mood/quality of life
Coronary collateral circulation
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
As adults age, their cardiovascular responses change
Decreases: maximal cardiac output, stroke volume, heart rate
Increases: maximal systolic blood pressure, diastolic blood pressure, mean arterial pressure
Training intensity
most important factor in maintaining cardiovascular fitness
Endurance training
increases blood volume, cardiac dimensions, mass, size of coronary vascular bed, internal diameter of coronary arteries
= arteries more distensible/stretch/expand during exercise
