E1: Atrial And Ventricular Dysrhythmias Flashcards by Katie Seils

Where do sinus rhythms originate?

The sinoatrial node

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Why can sinus tachycardia be dangerous?

It can increase myocardial oxygen consumption, which can aggravate ischemia and infarction, particularly in those with cardiovascular disease

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What is sinus dysrhythmia?

Same as NSR, but with patterned irregularity

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When does the rate in a sinus dysrhythmia increase and decrease?

Increases during inspiration and decreases during expiration

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What is the difference between a sinus pause and a sinus arrest?

A sinus pause is when 1-2 beats are dropped, and a sinus arrest is when 3 or more beasts are dropped

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What is sinus node dysfunction (sick sinus syndrome) characterized by?

Characterized by periods of bradycardia, tachycardia, prolonged pauses or alternating bradycardia and tachycardia

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What is the treatment for sinus node dysfunction?

Treatment may require a pacemaker for the slow rhythms and medication for the fast rhythms

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What are the 3 mechanisms that cause atrial dysrhythmias?

1) automaticity
2) triggered activity
3) reentry

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What are the 3 key characteristics of atrial dysrhythmias?

1) P waves that differ in appearance from the normal sinus P waves
2) Abnormal, shortened, or prolonged PR intervals
3) QRS complexes that appear narrow and normal

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What is a wandering atrial pacemaker?

When the pacemaker site shifts between the SA node, Atria, and/or the AV junction
produces characteristic features of P waves that change in appearance frequently

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What causes wandering atrial pacemaker?

Inhibitory vagal effect of respiration on the SA node and AV junction

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What are premature atrial complexes (PACs)?

Early ectopic beats that originate outside the SA node

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How can you identify PACs on EKG?

There are P waves that are upright preceding each QRS complex, but have a different morphology than the normal P waves of the underlying rhythm
-There is also a non-compensatory response

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What is a non-compensatory response?

A pause where there are less than two full R-R intervals between the R wave of the normal beat which precedes the PAC and the R wave of the first normal beat which follows it

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What are PACs called when they are associated with wide QRS complexes?

PACs with aberrant ventricular conduction

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What is atrial tachycardia?

Rapid dysrhythmia that arises from the atria

- rate is so fast that is overrides the SA node

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What is paroxysmal atrial tachycardia?

Short bursts of atrial tachycardia

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What is multifocal atrial tachycardia?

A pathological condition that presents with changing P wave morphology and heart rate of 120-150 bpm
the rhythm is irregular due to multiple foci
Same features as wandering atrial pacemaker, but faster rate

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What is SVT?

Tachycardia that arises from above the ventricles but cannot be definitely identified as atrial or junctional tachycardia because the P waves cannot be seem sufficiently

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What causes atrial flutter?

Rapid depolarization reentry circuit in the atrial at a rate of 250-350 bpm

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If you see a saw tooth appearance on EKG, what should you think of?

Atrial flutter

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What is atrial fibrillation?

Chaotic, asynchronous firing of multiple areas within the atria
-totally irregular rhythm with no discernible P waves

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What are patients with atrial fibrillation at increased risk for?

Patients may develop intra-atrial emboli as the atria are not contracting and blood stagnates in the atrial chambers forming a thrombus
-predisposes patients to systemic emboli and stroke

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What are junctional dysrhythmias?

Dysrhythmias that originate in the AV junction

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What are the key characteristics of junctional dysrhythmias?

1) P waves may be inverted with a short PR interval, they may be absent (buried within he QRS), or they may follow the QRS 2) QRS complexes are usually normal

What are premature junctional complexes (PJCs)?

Single early electrical impulse that arises from the AV junction

What is the typical rate of a junctional escape rhythm?

40-60 | -arises from AV junction

What is the typical rate of an accelerated junctional rhythm?

60-100 | -arises from the AV junction

What is junctional tachycardia?

A fast ectopic rhythm that arises from bundle of His at a rate of 100-180

When do ventricular dysrhythmias occur?

- When the atria, AV junction, or both are unable to initiate an electrical impulse - Or when there is enhances automaticity of the ventricular myocardium

What are the 3 key features of ventricular dysrhythmias?

1) wide and bizarre QRS complexes 2) T waves in the opposite direction of the R wave 3) absence of P waves

What are premature ventricular complexes (PVCs)?

- Early ectopic beats that interrupt the normal rhythm - originate from an irritable focus in the ventricular conduction system or muscle tissue - retrograde impulse inhibits conduction of a normally fired SA node impulse; SA node timing is unaffected

PVCs that look the same are called ***. PVCs that look different from each other are called ***.

Unifocal | Multifocal

Two PVCs in a row are called a ***. What does this indicate?

Couplet Extremely Irritable ventricles

PVCs that fall between two regular complexes and do not disrupt the normal cardiac cycle are called ***.

Interpolated PVCs

What is an idioventricular rhythm?

A slow dysrhythmia (20-40) with wide QRS complexes that arise from the ventricles -Rhythm of last resort

What is an accelerated idioventricular rhythm?

An idioventricular rhythm that exceeds the inherent rate of the ventricles (40-100)

What is ventricular tachycardia?

``` Fast dysrhythmia (100-250) that arises from the ventricles -always clinically significant, potentially unstable, and may lead to cardiac arrest ```

Ventricular tachycardia is present when there are 3 or more *** in a row?

PVCs

What is torsades de pointes?

A unique variant of polymorphic ventricular tachycardia - may be associated with prolonged QT - may be drug induced or associated with electrolyte abnormalities

What is the management of torsades if the patient is in cardiac arrest?

Defibrillation

What is the management of torsades if the patient is not in cardiac arrest?

Infusion of magnesium sulfate

What happens in ventricular fibrillation?

- results from chaotic firing of multiple sites in the ventricles - causes heart muscle to quiver rather than contract efficiently, producing no effective muscular contraction and no cardiac output

What is the clinical presentation of someone in ventricular fibrillation?

Cardiac arrest, unresponsive, and pulseless

What is the most common cause of prehospital death in adults?

Ventricular fibrillation

What is pulseless electrical activity?

A condition that has an organized electrical rhythm on the ECG monitor, but patient is pulseless and apneic

What is a heart block?

A partial delay or complete interruption in the cardiac conduction pathway between the atria and ventricles

What are the common causes of heart blocks?

Ischemia, myocardial necrosis, degenerative disease of the conduction system, congenital anomalies, and drugs

What is 1st degree heart block?

- a consistent delay in conduction at the level of the AV node - not a true block

What will you see on EKG if the patient has 1st degree heart block?

Prolonged PR interval

What is 2nd degree heart block type 1 also known as?

Wenckebach or Mobitz 1

What is 2nd degree heart block type 1?

An intermittent block at the level of the AV node

What will you see on EKG if the patient has 2nd degree heart block type 1?

- More P waves than QRS complexes and rhythm has patterned irregularity - PR interval progressively increases until a QRS complex is dropped - after dropped beat, the next PR interval is shorter

What is 2nd degree heart block type 2 also known as?

Mobitz II

What is 2nd degree heart block type 2?

Intermittent block at the level of the bundle of his or bundle branches resulting in atrial impulses that are not conducted to the ventricles

What will you see on EKG if a patient has 2nd degree heart block type 2?

- More p waves than QRS complexes - PR interval is prolonged and the duration of the PR interval remains constant - Intermittently a P wave occurs and is not followed by a QRS complex

What does 2nd degree heart block type 2 often progress to?

3rd degree (complete) heart block

What is 3rd degree heart block?

Complete block of conduction at or below the AV node | -impulses from the atria cannot reach the ventricles

What happens in 3rd degree heart block?

The atrial pacemaker is the SA node (60-100) and the ventricle pacemaker is an escape rhythm from the AV junction (40-60) or from the ventricles (20-40)

What will you see on EKG if the patient has 3rd degree heart block?

- Upright and round P waves seem to “march right through the QRS complexes” - No association between the P waves and the QRS complexes

E1: Atrial And Ventricular Dysrhythmias Flashcards

(60 cards)