Chapter 6 Flashcards
What are atrial dysrhythmias caused by?
Ectopic impulses in either atria which affects the SA node and increases the heart rate
Ectopic impulses
Referes to an electrical impulse that comes from outside of the normal pacemaker site or electrical conduction pathway.
What dysrhythmias are caused by ectopic impulses?
Premature atrial complexes, atrial tachycardia, atrial flutter, and atrial fibrillation
Atrial dysrhythmias occur from conditions such as
Damage to the atria from MI, valvular problems, ot neurological influences
Which wave form is affected by the change in electrical activity within the atria?
P waves
What are premature atrial complexes (PAC)
Electrical impulses that originate in the atria and initiate an early impulse that interrupts the inherent regular rhythm. The atria do not achieve the maximum lood capacity prior to contraction, lack of blood causes low cardiac output and less volume in the ventricles prior to ventricular contraction.
PAC criteria for classification
A PAC is a cardiac complex that occurs too soon. It has a positively deflected P wave. Other than being “early”, this complex does not possess nay abnormal features
Biphasic
The waveform that has two phases; an equally positive (upward) and negative (downward) deflection on the ECG tracing
Trigeminy
Refers to a pattern in wich every third complex is a premature beat
How to determine a PAC
Determine the underlying rhythm of NSR, S.Brady, S.Tachy or S.Dys followed by a description of the PAC (ex: sinus rhythm with trigeminal PACs
Signs and sx’s
Those of low cardiac output, palpitations , depend on frequency of PACs
Wandering Atrial Pacemaker (WAP)
Rhythm in which the pacemaker site shifts between the SA node, atria, and/or the AV junction. P wave configuration changes in the same lead
When is WAP a normal finding?
WAP is a normal finding in children, older adults, and well-conditioned athletes
Signs and sx’s of WAP
None. May be related to some types of organic heart disease and drug toxicity
WAP criteria and classification
Has a changing P wave configuration with at least three variations in one lead. The rhythm may be irregular
Multifocal Atrial Tachycardia (MAT)
Has a P wave that changes from beat to beat and a heart rate of 101 to 150. It has the same characteristics as wandering atrial pacemaker (WAP), with the only difference being that the rate is in excess of 100.
MAT criteria and classification
MAT has a clearly changing P wave and a heart rate of 101 to 150 beats per minute
Atrial flutter
Occurs when rapid impulse originates in the atrial tissue. Has several F waves. Will lead to more serious dysrhythmias if not treated.
Ectopic focus origin in atrial flutter
From ischemic areas of the heart with enhanced automaticity of from a reentry pathway (sawtooth shape)
What is a reentry pathway
An extra pathway that has developed where a group of cells will generate an impulse faster than the SA node (similar to finding a shortcut to school or work and bypassing traffic)
How is atrial flutter described
The ratio of F waves to QRS complexes. Ex: atrial flutter 3:1
Atrial flutter rate
Atrial rate will be between 250 and 350 bpm
Atrial flutter criteria and classification
“sawtooth” atrial pattern between the QRS complexes, no identifiable P waves exist, PR interval cannot be measured. All other measures are noted as WNL
What is loss of atrial flick
Occurs when blood is ejected into the ventricles by the atrial immediately prior to ventricular systole, sp atrial do not contract completely
Signs and sx’s of atrial flutter
None if the heart rate remains between 60-100, if it increases there will be sx’s of low cardiac output
Tx for atrial flutter
Oxygen therapy to ensure adequate supply to the vital organs and constant monitoring of rhythms so that it does not advance to atrial fibrillation
Atrial fibrillation
Occurs when electrical impulses come from area of reentry pathways or multiple ectopic foci. Each electrical impulse depolorizes only a small area of the atria resulting in the failure fo the whole atria to contract as a whole, causing a quiver, blood is not pumped properly.
What is the cardiac output in atrial fibrillation
Up to 30%
What is the appearance of atrial fibrillation?
Fine scribbles, no P wave, chaotic
Atrial rate in atrial fibrillation
375-700 bpm
Atrial fibrillation criteria for classification
Shows chaotic atrial electrical activity with irregular R-R intervals. There is chaotic F waves
Signs and sx’s of atrial fibrillation
Those of decreased cardiac output. Loss of atrial kick. New onset Afib may present with dizziness, nausea, etc.
Tx of atrial fibrillation
Use of medications first, then cardioversion if necessary to stabilize the pt’s hr
Possible conditions due to atrial fibrillation
Blood accumulated in the atria due to incomplete contraction of the atria which can allow the opportunity for a clot or thrombus to form. Increased risk of embolism. They may also be at risk to develop cerebral vascular accident (CVA), MI, PE, renal infarction or an embolism
What are the similarities between atrial dysrhythmias
They are caused by an ectopic impulse in either of the atria
PAC
Premature atrial complexes which are impulses that originate in the atria and initiate an early impulse that interrupts the inherent regular rhythm
Identify wandering atrial pacemaker using the criteria for classification and explain how the rhythm may affect the pt, including basic pt care and tx
WAP is a rhythm in which the pacemaker site shifts between the SA node, atria, and/or the AV junction. The P wave configuration changes in appearance during the pacemaker shift
Identify multifocal atrial tachycardia using the criteria for classification and explain how the rhythm may affect the pt, including basic pt care and tx
MAT has a P wave that changes form beat to beat and heart rate of 101 to 150 bpm
Identify atrial flutter using the criteria for classification and explain how the rhythm may affect the pt, including basic pt care and tx
A flutter occurs when a rapid impulse originates in the atrial tissue. This dysrhythmia presents with a classic sawtooth or picket fence appearance known as flutter or F waves
Identify atrial fibrillation using the criteria for classification and explain how the rhythm may affect the pt, including basic pt care and tx
A fib occurs when electrical impulses come from areas of reentry pathways or multiple ectopic foci. Each electrical impulse results in depolarization of only a small group of atrial cells rather than the whole attrai. This dysrhythmia presents with classic chaotic “f” waves between the irregular R-R intervals
