Alteration in Perfusion: Atrial Rhythms

Atrial dysrhythmias occur when the

sinus node fails to fire or an irritable cell/cells in the atria decide to become the pacemaker.

Atrial Dysrhythmias

• Changes  are in the P wave (flattened, notched, irregular or peaked).

• The QRS is Generally normal .12 sec or smaller

Wandering Pacemaker

• The pacemaker site wanders between the sinus node, the atria, and the AV junction.

• Although each impulse originates from a different focus, rate usually remains within a normal range, but it can be slower or faster.

Wandering Pacemaker conduction

• Conduction through to the ventricles is normal.

Atrial Ps

Rules for Wandering Pacemaker

• Regularity: Slightly irregular

• Rate: Usually normal, 60–100 bpm

• P Wave: Morphology changes from one complex to the next

• PRI: Less than 0.20 second; may vary

• QRS: Less than 0.12 second

• Rarely causes symptoms

Mechanism of Premature Atrial Complex

• The pacemaker is an irritable focus within the atrium that fires prematurely and produces a single ectopic beat.

• Conduction through to the ventricles is normal.

Mechanism of Premature Atrial Complex: rhythm

• This is a single beat, not an entire rhythm.  The underlying rhythm also must be identified.  

• PAC may feel like an irregular pulse.

Rules for Premature Atrial Complex: Regularity, rate, P wave

• Regularity: Depends on the underlying rhythm; regularity will be interrupted by the PAC

  • underlying rhythm__ with PAV 

• Rate: Depends on the underlying rhythm

• P Wave: P wave of early beat differs from the sinus P waves; can be flattened or notched; may be lost in the preceding T wave

Rules for Premature Atrial Complex: PRI and QRS

• PRI: 0.12–0.20 second; can exceed 0.20 second

• QRS: Less than 0.12 second

Rules for Premature Atrial Complex

• Sinus rhythm with PAC 

• There is still a p before the qrs,

• Count the pac when counting the rate

Premature Atrial Contraction: Significance

• Usually benign

• Can be early sign of HF

• Can lead to atrial tachyarrhythmias

Premature Atrial Contraction: causes

•  fatigue, hypoxia, dig-toxicity, caffeine, ischemia, HF, alcohol, medications, amphetamines, heart disease and mitral prolapse

Premature Atrial Contraction: treatment and assessment

• Assessment: if many occur may feel dizzy

• Treat: Cause, B adrenergic blockers, monitor 

Mechanism of Atrial Tachycardia

• The pacemaker is a single irritable site within the atrium that fires repetitively at a very rapid rate. Conduction through to the ventricles is normal.

Rules for Atrial Tachycardia

• Regularity: Regular

• Rate: 150–250 bpm

• P Wave: Atrial P wave; differs from sinus P wave; can be lost in T wave (P and T waves are smushed)

• PRI: 0.12–0.20 second

• QRS: Less than 0.12 second

Atrial Tachycardia significance

• Very dangerous in AMI or heart disease

• Commonly caused by dig-toxicity

• Can also be called Paroxysmal (sudden) Atrial Tachycardia(PAT)

Atrial Tachycardia clincial picture

• Rapid, regular pulse

• May show signs/symptoms of drop in cardiac output

• Can cause pulmonary edema, HF, shock (Immediately have the patient bear down to help lower HR) 

Atrial tachycardia treatment

• Tx: vagal maneuv, adenosine (rapid), Ca chnl blkr (diltiazem), B blkr (atenolol, propranolol), amiodarone, oxygen, cardiovert (low voltage) 

Mechanism of Atrial Flutter

• A single irritable focus within the atria issues an impulse that is conducted in a rapid, repetitive fashion.

• Those that do get through are conducted normally.

Mechanism of Atrial Flutter: To protect the ventricles from receiving too many impulses, the

AV node blocks some of the impulses from being conducted through to the ventricles. 

Rules for Atrial Flutter

• Regularity: Atrial rhythm is usually regular; ventricular rhythm is usually regular but can be irregular if there is variable block

• Rate: Atrial rate 250–350 bpm; ventricular rate varies

• P Wave: Characteristic sawtooth pattern (F waves)

• PRI: Unable to determine

• QRS: Less than 0.12 second

Atrial Flutter significance

• Rapid ventricular rate and loss of atrial kick (20%) can drop cardiac output

• Risk of pulmonary and cerebral emboli

• Can cause HF or myocardial ischemia

atrial flutter is seen in

• CAD,

• rheumatic heart disease,

• alcoholism,

• thyroid disease,

• rheumatic heart disease

Atrial contraction forces

additional volumes of blood into the ventricles (often referred to as "atrial kick").

The atrial kick contributes a significant volume of blood toward ventricular preload (approximately 20%)

Atrial Flutter clinical picture

• Pulse can be regular or irregular, fast or slow

• Signs/symptoms of low cardiac output: SOB, palpitations, dizzy, chest pain

Atrial Flutter Tx

• Oxygen 2 liters first thing you need is oxygen and then medication

• Ca chnl: diltiazem, amlodipine

• B blks: (olol), metoprolol, atenolol

• Anticoagulants: warfarin, heparin, enoxaparin

• Antiarrhythmics: amiodarone (brings it to be a reg rhythm) 

• Alternate Option: Cardioversion (synchronized) or Radiofrequency catheter ablation  

• first thing you need is oxygen and then medication

Mechanism of Atrial Fibrillation

• The atria are so irritable that a multitude of foci initiate impulses, causing the atria to depolarize repeatedly in a fibrillatory manner. 

• The AV node blocks most of the impulses, allowing only a limited number through to the ventricles.

In atrial fib, the av node

holds the electricity for longer, there is a lot of p’s and then a qrs, we can use cardioversion

• Conduction: AV nodes blocks some impulses but allow others to proceed normally through the ventricles

Rules for Atrial Fibrillation

• Regularity: Grossly irregular

• Rate: Atrial rate greater than 350 bpm; ventricular rate varies greatly

• P Wave: No discernible P waves; atrial activity is referred to as fibrillatory waves (f waves)

  • we don’t know which one causes the qrs is because of that we can’t measure PRI 

• PRI: Unable to measure

• QRS: Less than 0.12 second 

Atrial Fibrillation image

Atrial Fibrillation controlled vs uncontrolled

• Ventricular response irregularly, irregular

• Goal to keep ventricular rate less than or equal to 100 to keep CO intact- controlled Atrial Fibrillation.

• If HR greater than 100 – uncontrolled A fib.  Sometimes noted as a fib with a rapid ventricular response.

• Blood is sitting in the atrial for a extended time which leads to clots 

Atrial Fibrillation cause and assessment

• Cause: the same as A flutter

• Assessment : dizziness, chest pain, anxiety, syncope, hypotension

• Client at risk for mult. thrombi, stroke

• If client has valvular disease, risk higher

Atrial Fibrillation treatment

• Tx: if new onset and caught, then drugs same as A flutter. 

• If no response –Cardioversion or Radiofrequency catheter ablation 

• Take pulse for one full minute

• Anticoagulants, Rate Controlling drug (ie. dig or lopressor) for life

Treatment: Radiofrequency Catheter Ablation Therapy

• Electrode-tipped ablation catheter “burns” accessory pathways or ectopic sites in the atria, AV node, and ventricles. 

Treatment: Radiofrequency Catheter Ablation Therapy Nonpharmacologic treatment for

• AV nodal reentrant tachycardia

• Reentrant tachycardia related to accessory bypass tracts

• Control of ventricular response of certain tachydysrhythmias 

• The R wave has to be shocked→ if not leads to more serious problems 

Treatment: Cardioversion

• Synchronized counter shock (synchronized to R waves). 

  • The shock depolarizes the myocardium simultaneously.

  • Firing on the patient’s t waves can lead to ventricular arrhythmias.

• The shock stops abnormal rhythm and allows the sinus node to assume pacing

• This is an elective procedure

• Signed consent-Light anesthetic agent and sedative given.

Before Cardioversion, if not new…

• If patient has been in atrial fibrillation for >48 hours, anticoagulation therapy with warfarin (Coumadin) is recommended for 3 to 4 weeks before cardioversion and for 4 to 6 weeks after successful cardioversion. Poss dislodge of clot.

• Digitalis must be held for 48 hrs. prior to cardioversion.

  • Hold dig since it lower heart 

Cardioversion Nursing Care

• Check placement of “pads/paddles”

• Shock is delivered while client is exhaling

• Be sure all personnel are clear

• Have crash cart ready

• Start with 50-100 joules (lower volts) 

• Maintain patent airway

• O2 needed

• Assess client vital signs and LOC

• Monitor for dysrhythmia

• Document rhythm strips  before, during, and after

• Assess for chest burns

• Provide emotional support for client

• Complications: PE, CVA, MI