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Chapter 2
•
Cardiovascular Care
ARRHYTHMIA DISORDERS
ATRIAL FIBRILLATION
AF is a rhythm that is characterized
by an irregular rhythm resulting in
disorganized atria contraction and
lack of synchronization between
the atria and ventricles. The atria
rate may be as fast as 400 beats/min
and the ventricular rate will be an
irregular 120 to 200 beats/min.
AF usually occurs in a patient who
has underlying heart disease such
as CAD, rheumatic heart disease,
cardiomyopathy, hypertension, HF,
and pericarditis. The ineffective atrial
contractions and/or rapid ventricular
response leads to decreased cardiac
output. There is a great potential for
clot formation to develop because of
the blood stasis that develops in the
heart as the chambers do not have
enough time to empty completely
between each beat. These clots can
travel to the brain leading to a stroke.
AF, accounts for 20% of all strokes.
On the EKG, there will be no
P waves or the P waves are erratic,
irregular, baseline fibrillatory waves.
The QRS complexes are of uniform
configuration and duration. AF is
most commonly due to hypertension,
HF, and increasing age.
PICTURING
PATHO
Atrial arrhythmias
●
Premature atrial contractions
●
Atrial fibrillation
●
Atrial flutter
Atrioventricular (AV) blocks
●
First-degree AV block
●
Second-degree AV block
●
Third-degree AV block
Junctional arrhythmias
●
AV junctional rhythm
Ventricular arrhythmias
●
Premature ventricular
contractions
●
Ventricular fibrillation
●
Ventricular tachycardia
Sinus node arrhythmias
●
Sino-atrial block
●
Sinus bradycardia
●
Sinus tachycardia
In AF the heart rhythm is irregular and there is no distinct P wave since the impulses are not arising from the SA node. (Reprinted with
permission from Martindale JL, Brown DFM.
A Visual Guide to ECG Interpretation
. 2nd ed. Philadelphia: Wolters Kluwer; 2016.)
In AF, electrical stimulation does
not begin at the SA node but
instead at other, ectopic areas
within the atria or at the pulmonary
vein. This causes an irregular
rhythm as well as an increase in
the heart rate. (Reprinted with
permission from Stewart JG.
Anatomical Chart Company Atlas
of Pathophysiology
. Philadelphia:
Wolters Kluwer; 2018.)