Atrial Dysrhythmias Notes

Atrial Dysrhythmias

Atrial Dysrhythms

  • Premature Atrial Contractions (PAC’s)
  • Paroxysmal Atrial Tachycardia (PAT) or Supraventricular Tachycardia (SVT)
  • Atrial Fibrillation
  • Atrial Flutter

Causes of Atrial Dysrhythmias

  • Stress
  • Electrolyte imbalances
  • Hypoxemia
  • Atrial injury
  • Digitalis toxicity
  • Hypothermia
  • Hyperthyroidism
  • Alcohol
  • Pericarditis
  • Increased automaticity in the atrium
  • Generally, have P-wave changes

Premature Atrial Contractions (PAC)

  • A single contraction occurs earlier than the next expected sinus contraction
  • After PAC, it resumes the underlying rhythm
  • Underlying rhythm is sinus (SB, SR, ST)
  • P waves and PR interval may vary
  • Noncompensatory pause
  • P wave may be found in T wave

EKG Characteristics of PAC

  • Rhythm: regular except for PAC’s
  • Rate: depends on underlying rhythm
  • P waves: Present; in PAC, may have a different shape
  • PR interval: varies in PAC; otherwise, normal (0.12-0.20 sec)
  • QRS complex: 0.12 or less

Common Causes of PACs

  • Hypokalemia
  • Hypomagnesemia
  • Hypoxia
  • Medication
  • Caffeine
  • ETOH
  • Anxiety
  • Atrial ischemia

Nursing Interventions for PACs

  • Palpate pulse
  • Chronic or new onset?
  • Assess for cause
  • Trend
  • Treatment – not necessary unless 6+/min
  • Treat possible cause
  • Beta blockers
  • Monitor for more serious dysrhythmias

Risks Associated with PACs

  • Patients at higher risk for atrial fibrillation

Blocked Premature Atrial Contractions or Non-Conducted PAC

  • Pause noted on rhythm strip
  • Premature P wave
  • May alter cardiac output

Wandering Atrial Pacemaker (WAP)

  • The pacemaker site transfers from the SA node to other latent pacemaker sites in the atria & the AV junction & then moves back to the SA node.
  • Varying configurations of P waves
  • At least three different looking P waves determined by focus in atria
  • HR < 100
  • Irregular Rhythm
  • PRI varies determined by focus
  • QRS Complex normal (0.06 – 0.12 sec)
  • WAP may occur in normal hearts as a result of fluctuation in vagal tone.
  • Seen in patients with heart disease or COPD

PSVT: Paroxysmal SVT

  • Abrupt onset and abrupt cessation
  • Atrial impulse is conducted to an area in the AV node that causes the impulse to be rerouted over and over again at a fast rate
  • Causes: excessive alcohol, caffeine, nicotine, stress, anxiety in healthy adults, CAD, valvular problems, and hypoxemia
  • S/S: angina, hypotension, lightheadedness, palpitations, & intense anxiety
  • Underlying pathophysiologies: CAD & Cardiomyopathy

Paroxysmal Atrial Tachycardia PAT, PSVT

  • Rapid onset w/o warning that stops suddenly
  • HR 151 - 250 BPM
  • Irregular Rhythm
  • P waves (if present) may merge in T waves
  • PR Interval usually not possible to measure
  • QRS complex normal (0.06-0.12 sec)
  • Hemodynamic effects vary

Supraventricular Tachycardia (SVT)

EKG Characteristics of SVT

  • With a fast rate that the P waves may not be seen; frequently buried in the T waves
  • Rate 151 to 250 beats per minute
  • Rhythm Regular
  • P Waves Unable to distinguish P waves from T waves; frequently buried in preceding T waves & difficult to see
  • PRI Unable to determine; not possible to measure
  • QRS Complexes Narrow/normal (0.06-0.12 sec)

SVT Interventions

Nursing Interventions

  • Vital Signs (including SpO2)
  • Oxygen if hypoxic
  • ↓ HOB for hypotension
  • Assess for chest pain
  • Assess for shock (cool clammy skin, ALOC)
  • 12 Lead EKG
  • IV access

Vagal Maneuvers

Pharmacologic Interventions

  • Adenosine IV
    • 6 mg rapid IVP, follow with NS flush
    • If SVT does not convert in 1-2 minutes, give 12 mg rapid IVP, follow with NS flush
  • Verapamil or Diltiazem, IV Beta Blockers, Calcium Channel Blockers, Amiodarone

Electrical Interventions

  • Synchronized Cardioversion
  • Narrow regular QRS: 50-100 Joules

Synchronized Cardioversion

  • Choice of electrical therapy for ventricular (VT with a pulse) or supraventricular tachydysrhythmias
  • Synchronized circuit delivers a countershock on the R wave of the QRS complex of the EKG

Procedure

  • Procedure similar to defibrillation except sync button turned ON
  • If patient stable, sedate prior
  • Initial energy lower
    • 50–100 joules (biphasic)
    • 100 joules (monophasic)
  • If patient becomes pulseless, turn sync button off and defibrillate

Atrial Fibrillation (A-fib)

  • Because of the quivering of the atrial muscle, and because there is no uniform wave of depolarization in atrial fibrillation, there is no P wave
  • Rapid, erratic electrical discharge comes from multiple atrial ectopic foci
  • Instead, the baseline appears erratic (wavy)
  • Wavy deflections are termed “fibrillatory” waves
  • Results in loss of atrial kick & Cardiac Output by 30%
  • High risk for pulmonary or systemic emboli
  • Cause: Erratic, irregularly irregular impulse formation in atria

Types of Atrial Fibrillation

  • Paroxysmal or persistent
  • Controlled vs uncontrolled/rapid

General Information

  • Most common dysrhythmia
  • Prevalence increases with age
  • Usually occurs in patients with underlying heart disease
  • Can also occur with other disease states
  • As with atrial flutter – causes a decrease in CO and an increased risk of stroke
  • S/S depends on the ventricular response rate
  • palpitations, CP/chest pressure/discomfort, SOB, lightheadedness, fatigue or lack of energy, exercise intolerance

EKG Characteristics of Atrial Fibrillation

  • PR Interval Not measurable
  • QRS Complex Normal (0.06-0.12 sec)
  • P Waves No identifiable P waves; instead, there are fibrillatory waves that are present giving an erratic, wavy baseline [wavy baseline could be coarse or fine)
  • Rhythm Ventricular rhythm irregularly irregular
  • Rate Atrial rate usually greater than 400 to 600 beats/min; ventricular rate variable [“Controlled” A-fib has a ventricular rate of less than 100; “uncontrolled” has ventricular rate > 100]

Atrial Fibrillation Interventions

Nursing Interventions
  • Rate dependent
  • Vital Signs (including SpO2)
  • Oxygen if hypoxic
  • ↓ HOB for hypotension
  • Assess for chest pain
  • Assess for shock (cool clammy skin, ALOC)
  • 12 Lead EKG (new onset)
  • IV access
Pharmacologic Interventions
  • Beta-blockers
  • Amiodarone
  • CCBs
Medical Interventions
  • Ablation
  • Electrical cardioversion
  • Maze procedure with cryoablation

Atrial Flutter

  • Atrial flutter is an ectopic atrial rhythm in which an irritable site depolarizes regularly at an extremely rapid rate
  • The extremely rapid atrial rate results in waveforms that resemble the teeth of a saw, or a picket fence
  • Known as “Flutter” waves
  • Flutter waves or Classic “sawtooth” pattern in leads II, III, and aVF
  • The AV node conducts impulses to the ventricles at a 2:1; 3:1; 4:1 or greater ratio
  • The degree of AV block may be consistent or variable

EKG Characteristics of Atrial Flutter

  • PR Interval Not measurable
  • QRS Complex Usually normal (0.06-0.12 sec)
  • P Waves No identifiable P waves; saw-toothed “flutter” waves are present
  • Rhythm Atrial rhythm regular. Ventricular rhythm regular or irregular depending on AV conduction/blockade
  • Rate Atrial rate - fast, regular (250-350 bpm); the ventricular rate is variable and is determined by the degree of AVB: 3:1, 4:1, etc. The ventricular rate will usually not exceed 180 beats/min due to the intrinsic conduction rate of the AV junction.

Causes of Atrial Flutter

  • Ischemia
  • CAD/heart failure/HTN
  • Hardening of the arteries/arteriosclerosis
  • Heart valve disease
  • Cardiomyopathy/heart muscle damage
  • Congenital heart disease
  • Alcohol consumption
  • Hyperthyroidism

Atrial Flutter Interventions

Symptoms
  • depend on the ventricular response rate
  • SOB, tiredness, CP, palpitations, anxiety lightheadedness, fainting
Nursing Interventions
  • Rate dependent
  • Check if patient is symptomatic (take VS)
  • 12 Lead EKG (if new onset)
Pharmacologic Interventions
  • Beta-blockers
  • CCBs
Medical Interventions
  • Radiofrequency Ablation
  • Electrical Cardioversion

Wolff-Parkinson-White Syndrome

EKG Characteristics

  • An accessory conduction pathway is present between the atria & the ventricles
  • Electrical impulses may be rapidly conducted to the ventricles
  • The rapid impulses create a slurring of the initial portion of the QRS; slurred effect is called a delta wave
  • PR Interval Short (less than 0.12 sec)
  • QRS Complex Wide (greater than 0.12 sec); delta wave present
  • P Waves Normal (upright & uniform) unless A. Fib is present
  • Rhythm Regular unless associated with atrial fibrillation
  • Rate Depends on rate of underlying rhythm