ECG Dysrhythmias

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ECG Dysrhythmias

• Updated March 2006 D. Tucker, RPh, BCPS

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Overview

• ECG waveforms
• Normal sinus rhythm
• Asystole
• Bradycardia
• Ventricular fibrillation
• Ventricular tachycardia

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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

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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
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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

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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 patients life has
  ended

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ECG Rhythms

• Ventricular asystole

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Bradycardia

• Bradycardia is when the heart is lt 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

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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

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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 gt10
  beats/minute
• VT usually preceeds VF
• Causes of VT include myocardial ischemia, heart
  failure, drug toxicity from procainamide,
  quinidine, or cocaine

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ECG Rhythms

• Ventricular tachycardia

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Name TheseECG Rhythms
C
A
D
E
B