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Appendix B
Pathophysiology and Clinical
Implications of Arrhythmias
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Cardiac Output
 Total volume of blood pumped by heart
in one minute
Heart Rate x Stroke Volume = Cardiac Output
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
How Arrhythmias
Impact Cardiac Output
 Heart Rate:
 Bradycardias
 Tachycardias
 Stroke Volume:
 Ventricular rhythms
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Symptoms of Decreased
Cardiac Output




Anxiety
Chest pain
Shortness of breath
Diaphoresis




Hypotension
Cool, clammy skin
Cyanosis
Decreased
consciousness
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Treatment Principles
Mechanism
Treatment
Principle
Bradycardia
Rate is too
slow
Speed up rate
Tachycardia
Rate is too
fast
Slow down
rate
Ventricular
Irritability
Contraction is
erratic
Suppress
irritable focus
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Normal Sinus Rhythm
Significance
 Normal cardiac
pattern
Clinical Picture
 Does not produce
symptoms
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Sinus Bradycardia
Significance
 Can precede blocks or
asystole
 Can precipitate escape
rhythms or ventricular
irritability
 Can be caused by AMI,
vagal stimulation,
increased intracranial
pressure
 Can reflect normal,
athletic heart
Clinical Picture
 Slow, regular pulse
 Can cause
signs/symptoms of
decreased cardiac
output
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Sinus Tachycardia
Significance
 Usually a
compensatory
response to fever,
activity, pain,
anxiety,
hypovolemia, heart
failure, etc.
 Dangerous in AMI
(can extend infarct)
Clinical Picture
 Rapid, regular pulse
 Probably
asymptomatic
 Possibly
palpitations,
dyspnea
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Sinus Arrhythmia
Significance
 Common in children
and young adults
Clinical Picture
 Irregular pulse
 Rarely causes
symptoms
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Premature Atrial Contractions




Significance
Usually benign
Can be early sign of
CHF
Can lead to atrial
tachyarrhythmias
Causes include
fatigue, hypoxia,
dig-toxicity, caffeine,
ischemia, CHF,
alcohol
Clinical Picture
 Rarely causes
symptoms
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Wandering Pacemaker
Significance
 Normal; often seen
in very old or very
young, or in athletes
 Persistence of
junctional rhythm
can indicate heart
disease
Clinical Picture
 Rarely causes
symptoms
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Atrial Tachycardia
Significance
 Very dangerous in
AMI or heart
disease
 Commonly caused
by dig-toxicity
Clinical Picture
 Rapid, regular pulse
 May show
signs/symptoms of
drop in cardiac
output
 Can cause
pulmonary edema,
CHF, shock
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Atrial Flutter




Significance
Rapid ventricular
rate and loss of
atrial kick can drop
cardiac output
Risk of pulmonary
and cerebral emboli
Can cause CHF or
myocardial ischemia
Seen in CAD,
rheumatic heart
disease
Clinical Picture
 Pulse can be
regular or irregular,
fast or slow
 Rapid ventricular
rate can cause
signs/symptoms of
low cardiac output
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Atrial Fibrillation
Significance
 Very rapid rate can
lead to CHF or
myocardial ischemia
 Threat of pulmonary
or cerebral emboli
 Commonly caused
by dig-toxicity
Clinical Picture
 Irregular pulse, can
be fast or slow
 Can have pulse
deficit
 Can cause
signs/symptoms of
low cardiac output
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Premature Junctional
Contractions
Significance
 May precede AV
block
Clinical Picture
 Rarely causes
signs/symptoms
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Junctional Escape Rhythm
Significance
 Fail-safe
mechanism
 Can be normal, as
with athletes
Clinical Picture
 Slow pulse
 If rate is slow
enough, can cause
signs/symptoms of
low cardiac output
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Accelerated Junctional
Rhythm
Significance
 Indicates irritable
junction overriding
normal pacemaker
 Often caused by
AMI, open-heart
surgery,
myocarditis, digtoxicity
Clinical Picture
 Usually
asymptomatic
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Junctional Tachycardia
Significance
 Indicates irritable
junction overriding
normal pacemaker
 Often caused by
AMI, open-heart
surgery,
myocarditis, digtoxicity
Clinical Picture
 Rapid, regular pulse
 Can cause
signs/symptoms of
low cardiac output
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
First Degree Heart Block
Significance
 Can be caused by
anoxia, ischemia,
AV node
malfunction, edema
following open-heart
surgery, dig-toxicity
 Can lead to more
serious AV block
Clinical Picture
 Usually
asymptomatic
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Second Degree Heart Block,
Type I (Wenckebach)
Significance
 Common following
inferior MI
 Can progress to
more serious AV
block
Clinical Picture
 Irregular pulse
 Usually
asymptomatic
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Second Degree Heart Block,
Type II
Significance
 Can be caused by
anoxia, edema after
open-heart surgery,
dig-toxicity,
hyperkalemia,
anterior MI
Clinical Picture
 Slow rate can cause
signs/symptoms of
low cardiac output
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Third Degree Heart Block
Significance
 Can progress to
ventricular standstill
Clinical Picture
 Very slow rate and
abnormal
pacemaker site
severely impair
cardiac output
 Patients will
frequently be
unconscious from
poor perfusion
 Cardiac failure can
follow quickly
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Premature Ventricular
Contractions
Significance
 Indicate ventricular irritability;
increasing frequency indicates
increasing irritability
 Causes include
ischemia/infarction, hypoxia,
acidosis, hypovolemia,
electrolyte imbalance, caffeine,
smoking, alcohol
PVCs considered dangerous if:
– more than 6 per minute
– patterns (bigeminy,
trigeminy, etc.)
– couplets
Clinical Picture
 Patients can feel PVCs and
be distressed by them
 Pulse is irregular
 Perfusion usually not
impaired unless PVCs
become frequent
 Many factors can cause
chronic PVCs in adults
– runs
– R-on-T phenomenon
– multifocal
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Ventricular Tachycardia
Significance
Clinical Picture
 Can quickly
 Patient will begin to
progress to
lose consciousness
ventricular fibrillation
as perfusion drops
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Ventricular Fibrillation
Significance
 Lethal arrhythmia
 Indicative of
extreme myocardial
irritability
Clinical Picture
 Patient is clinically
dead
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Idioventricular Rhythm
Significance
 Carries poor
prognosis
 Often associated
with large MI and
damage to large
amount of
ventricular muscle
mass
Clinical Picture
 Patient is clinically
dead
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Asystole
Significance
 Carries very poor
prognosis
 Often seen after
patient has been in
arrest for some time
Clinical Picture
 Patient is clinically
dead
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Matrix of Clinical Impact
Fast
Supraventricular
RATE
Ventricular
PACEMAKER
Slow
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Matrix of Clinical Impact
RATE
Slow
Supraventricular
Sinus Bradycardia
Normal Sinus Rhythm
Sinus Arrhythmia
Sinus Tachycardia
Wandering Pacemaker
Atrial Flutter
Atrial Fibrillation
PACs
Atrial Tachycardia
Accelerated Junctional Rhythm
Junctional Escape Rhythm
Third Degree Heart Block
Ventricular
PACEMAKER
Fast
Normal
Idioventricular Rhythm
PJCs
Junctional Tachycardia
Supraventricular Tachycardia
First Degree Heart Block
Wenckebach
Second Degree Heart Block Type II
PVCs
Ventricular Tachycardia
Asystole
Ventricular Fibrillation
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Matrix of Clinical Impact
RATE
VENTRICULAR
IRRITABILITY
TACHYCARDIAS
BRADYCARDIAS
Supraventricular
Fast
Ventricular
PACEMAKER
Slow
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ
Matrix of Clinical Impact
RATE
Fast
DECREASE
RATE
SUPPRESS
IRRITABILITY
VENTRICULAR
IRRITABILITY
TACHYCARDIAS
INCREASE
RATE
BRADYCARDIAS
Supraventricular
Ventricular
PACEMAKER
Slow
Gail Walraven, Basic Arrhythmias, Sixth Edition
©2006 by Pearson Education, Inc., Upper Saddle River, NJ