Transcript ECG 2- student copyx

In Summary….
Understand?
Could you label this???
ECG Paper
ECG Paper and Standardization
• Standardization Signal
– Without a standardization signal, the ECG paper is merely
graph paper. By entering a signal, you place value on each
of the smallest squares.
– At 1 cm=1 mv each tiny square represents 0.1 mv in height
(amplitude) and 0.02 seconds in width (duration) at a
paper speed of 50 mm/sec.
– At a paper speed of 25 mm/sec, each tiny square
represents 0.04 seconds, every large box (5 small boxes)
represents 0.20 seconds, and every 15 large boxes (set) = 3
seconds.
– The calibration signal can be changed, if necessary, to
affect amplitude only.
Baseline or Isoelectric Line
Positive
charges
Negative
charges
Normal ECG Tracing
Common Technical Pitfalls
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Incorrect lead placement
Paper speed
Motion artifacts
Breathing/respiratory movement
Purring
Artifacts
• The word artifact is similar to artificial in the
sense that it is often used to indicate something
that is not natural (i.e. man-made). In
electrocardiography, an ECG artifact is used to
indicate something that is not "heartmade." These include (but are not limited to)
electrical interference by outside sources,
electrical noise from elsewhere in the body,
poor contact, and machine
malfunction. Artifacts are extremely common,
and knowledge of them is necessary to prevent
misinterpretation of a heart's rhythm
Muscle Tremor Interference
• If your patient is not calm and comfortable, or just really
nervous and shaky…the reading may look like this. Also
caused by happy, purring feline patients
• Reapplying or readjusting the clips may help
• A towel or blanket can be placed on patient to help calm
them
• You can also place your hand on the chest of the patient,
taking care not to apply too much pressure (will interfere
with reading)
Patient Movements
Electrical Interference
• Remember that rubber mat and how you
checked your machine for causes of bad
ground?
• Interference can be caused by other
machinery such as a pulse oximeter or BP
monitor that is hooked up to animal; even
fluorescent lighting
Loose Electrodes
ECG Tracings of Common Arrhythmias
• Please refer to your ECG handout
• Reading assignment VTDRG: Pg 205-220,
338-345
Classification of Arrhythmias
• Definition
– An abnormality in the rate, regularity, or site of
origin of the cardiac impulse
– A disturbance in conduction of the impulse such
that the normal sequence of activation of the atria
and ventricles is altered
Classification of Arrhythmias
• Normal sinus impulse formation
– Normal sinus rhythm
– Sinus arrhythmia
• Disturbances of sinus impulse formation
– Sinus bradycardia
– Sinus tachycardia
• Disturbances of supraventricular impulse formation
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Atrial premature complexes
Atrial tachycardia
Atrial flutter
Atrial fibrillation
Disturbances of ventricular
impulse formation
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Ventricular premature complexes
Ventricular tachycardia
Ventricular systole
Ventricular asystole
Ventricular fibrillation
Disturbances of impulse
conduction
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Sinus arrest or block
Atrial standstill
Ventricular pre-excitation
First-degree AV block
Second degree AV block
Third degree AV block
Left bundle branch block
Right bundle branch block
Building Blocks for Arrythymia
Interpretation
• Recognize the site of origin of the abnormal beat
• Recognize deviations from the normal rate of
automaticity for that site
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Site of Origin
– Atrial
• Positive deflection P waves are present with a constant P-R interval and normal
duration QRS complex
– Junctional
• Negative deflection P waves, or no P waves with a normally conducted short QRS
complex
– Ventricular
• No P waves are evident, QRS complexes are wide and bizarre appearing and may
be positive or negative polarity depending on which ventricle is the site of origin