Transcript ECG Dysrhythmias - IHMC Public Cmaps (2)

ECG Dysrhythmias
Updated March 2006: D. Tucker, RPh, BCPS
Overview
ECG waveforms
 Normal sinus rhythm
 Asystole
 Bradycardia
 Ventricular fibrillation
 Ventricular tachycardia

ECG Rhythm Strip
Electrocardiogram or ECG is used to
measure the activity of the heart
 ECG is used to represent the conduction of
electrical impulses from the atria to the
ventricles
 ECG is used to characterize rhythms and
conduction abnormalities of the heart

ECG Waveforms
P Wave
Electrical activation (depolarization) of the right then
left atrium due to discharge from the sinoatrial (SA)
node
PR Segment
Passage of the impulse through the atrioventricular
(AV) node and bundle of HIS
QRS Complex Electrical depolarization of the ventricles
ST Segment
Plateau phase
T Wave
Repolarization of the ventricle
U Wave
Repolarization of the HIS-Purkinje system
ECG Waveforms
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Normal Sinus Rhythm
Normal impulse conduction through the
heart
 Normal sinus rhythm (NSR) is the standard
against which all other rhythms are
compared
 NRS contains no ectopic or aberrant beats

ECG Rhythms

Normal sinus rhythm
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ECG Rhythms

Asystole

Bradycardia

Ventricular
fibrillation

Ventricular
tachycardia
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Asystole
Asystole is a cardiac standstill, i.e., flatline
 Asystole is the absence of electrical activity
in the venticles
 Asystole usually results from a prolonged
period of cardiac arrest without
resuscitation
 Asystole usually means the patient’s life has
ended

ECG Rhythms

Ventricular asystole
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Bradycardia



Bradycardia is when the heart is < 60 beats/minute
or when the heart rate is slower than expected
Sinus bradycardia usually occurs as a response to
a reduced demand for blood flow
Signs and symptoms might include:


Chest pain, shortness of breath
Hypotension, pulmonary edema, congestive heart
failure
ECG Rhythms

Sinus bradycardia
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Ventricular Fibrillation
Ventricular fibrillation (VF) occurs as a
result of electrical impulses coming from
multiple ectopic pacemaker in the ventricles
 VF results in no cardiac output as a result of
producing no effective ventricular
contractions
 With VF the ventricular muscle quivers
instead of contracting

ECG Rhythms

Ventricular fibrillation
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Ventricular Tachycardia
Ventricular tachycardia (VT) is a result of 3
or more ventricular contractions occur
earlier than expected resulting in a
ventricular rate of >10 beats/minute
 VT usually preceeds VF
 Causes of VT include myocardial ischemia,
heart failure, drug toxicity from
procainamide, quinidine, or cocaine

ECG Rhythms

Ventricular tachycardia
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Name These
ECG Rhythms
A
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D
E
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