Cardiovascular Disease-Atrial Fibrillation Flashcards
Atherosclerosis
A condition that develops when plague builds up in the walls of the arteries; causes to stop blood flow
*causes a heart attack or stroke (leading cause of death)
Heart Attack
blood clot stops blood flow to a part of the heart and therefore cardiac muscle cells die
Ischemic Stroke
the most common, when the blood vessel to brain gets blocked and brain cells die
Hemorrhagic Stroke
when the blood vessel within brain burst
Congestive Heart Failure
heart is not pumping blood as well as it should be
Arrhythmia
Abnormal rhythm of the heart
Heart valve problems
stenosis, regurgitation, mitral valve prolapse
Atrial Fibrillation
-upper heart chambers contract irregularly
-Most common cardiac arrhythmias
-2.7 million Americans have it
Quivering or irregular heartbeat
Multiple reentrant circuits in the atria
Ventricular Fibrillation
Disorganized contraction of the lower chambers of the heart
Bradycardia
Slow heart rate
Tachycardia
Very fast heart rate
Conduction Disorders
Heart does not beat normally
Premature contraction
early heart beat
ECG of A fib
missing P wave which is the absence of atrial depolarization
SA node may not start the contraction
-electrical current does not flow because the contractions are so rapid and disorganized
-AV node often cant regulate the chaotic current (vetnricles beat more often)
ECG of slow ventricular response
spacey small peaks
Moderate ventricular response
larger negative peaks
Rapid Ventricular Response
multiple large positive peaks
Conversion back to normal sinus rhythm
electrical cadioversion
radiofrequency ablation
maze procedure
electrical cardioversion
low voltage electric current to reset heart rhythm to normal sinus rhythm
pacemaker
radiofrequency ablation
use radio waves to manage arrhythmias, usually before pacemaker
maze operation
create scar tissue to block abnormal signal, direct electric signal through a controlled path to ventricle
Controlling ventricular rate response
Reducing overly high heart rate Medicines: digoxin beta blockers calcium channel blockers anti-arrhythmic
Digoxin
slow HR, at atria to ventricle through inhibition of sodium potassium adenosine triphosphatase
Beta-Blockers
slow HR
Antagonists that block the receptor sites for EPI and NE on adrenergic beta receptors of SNS
Calcium-Channel blockers
slow HR, reduce strength of cardiac muscle contraction
prevent or reduce the calcium channels
Preventing blood clots
antiplatelets
anticoagulants
antithrombotic
Exercise response on atrial fib
Rapid irregular ventricular heart rate
- HR is high at any workload
- reduced SV due to limited atrial assistance during diastole
- HR response can be affected by comorbid conditions and medications
- exercise capactiy is reduced by 15-20%
Exercise Testing considerations
- Age predicted heart rate max is not valid
- irregular ventricular response may make BP determination less precise or more difficult
- Beta-Blockers may reduce exercise capacity, decrease submaximal HR and BP
- Verapamil (Calcium Channel Blockers) may mask ischemia and decrease HR response to exercise
- Digoxin may control ventricular response; diffuse ST effects
Exercise Programming
because ventricular rate is so irregular… work rate or perceived exertion should be prescribed
Comorbidities are important to ascertain in population with AF
Must watch for HYPOTENSION
Short term effects of exercise on AF
reduced AF burden
reduced symptom severity
Long term effects of exercise on AF
increase AF freedom
reduced symptom severity
Potential Mechanisms of exercise on AF
Reversed atrial remodeling Weight loss Improved BP Improved glycemic control Reduced Inflammation Improved autonomic tone
