Atrial Disorders and Rhythms

Atrial Disorders

• Premature Atrial Contraction
• Paroxysmal Atrial Tachycardia
• Atrial Flutter
• Atrial Fibrillation
• Supraventricular Tachycardia

The Word on Atrial Rhythms

• Atrial rhythms usually are rapid and usurp the sinus rhythm.
• Occasionally, atrial rhythms will be slow.
• Treatment aims to return the heart to sinus rhythm.
• Impulses can start in one or multiple irritable foci.

Conduction

• Conduction from a single focus involves the atrium passing to the AV node and then the ventricle.
• Conduction starting in multiple foci involves multiple locations in the atrium, which pass to the AV node before reaching the ventricle.

PAC (Premature Atrial Contraction)

• The rate can occur at any rate.
• The regularity is regular but interrupted by premature beats.
• P waves are shaped differently from sinus P waves.
• PR interval measures 0.12-0.20 seconds.
• QRS interval is less than 0.12 seconds.
• Causes include stimulants, hypoxia, or heart disease.
• Adverse effects include other dysrhythmias, with early CHF acting as a sign.
• Treatments involve digitalis, quinidine, or oxygen and omitting stimulants.

Paroxysmal Atrial Tachycardia (PAT)

• The rate is 160-250.
• The regularity is regular but interrupts a slower rhythm.
• P waves are different from sinus P waves.
• PR interval measures 0.12-0.20 seconds.
• QRS measures less than 0.12 seconds.
• Causes are the same as PAC (Premature Atrial Contraction).
• Averse effects involve decreased cardiac output.
• Treatments involve digitalis, calcium channel blockers, beta-blockers, sedation, amiodarone, adenosine, and oxygen.

Atrial Flutter

• The atrial rate is 250-350, and the ventricular rate varies depending on conduction.
• The regularity can be regular or irregular.
• P waves are nonexistent, with flutter waves instead.
• The PR interval is not applicable.
• The QRS interval is less than 0.12 seconds.
• Causes include pulmonary embolus, valvular heart disease, lung disease, and thyrotoxicosis.
• Adverse effects include decreased cardiac output.
• Treatments involve digitalis, calcium channel blockers, beta-blockers, adenosine, and cardioversion.

Atrial Fibrillation

• The atrial rate is 350-700, and the ventricular rate varies depending on conduction.
• The regularity is irregularly irregular.
• P waves are nonexistent; a wavy baseline between QRSs is present instead.
• The PR is not applicable.
• The QRS is less than 0.12 seconds.
• Causes include MI, lung disease, valvular heart disease, and hyperthyroidism.
• Adverse effects are decreased cardiac output, along with blood clots causing stroke or pulmonary embolus.

Atrial Fibrillation Management

• If the duration is less than 48 hours, digitalis, calcium channel blockers, beta-blockers, amiodarone, and cardioversion are used.
• If the duration is more than 48 hours:
  • For non-emergent cases, anticoagulation occurs for 2-3 weeks, followed by cardioversion.
  • In emergencies, heparin, transesophageal echocardiogram to rule out atrial clots, and cardioversion are implemented.

Supraventricular Tachycardia (SVT)

• The rate is about 130 or higher; some texts cite 150 or higher.
• Regularity is regular.
• P waves are not seen.
• The PR is not measurable.
• The QRS measures less than 0.12 seconds.
• Causes involve stimulants, hypoxia, and heart disease.
• Adverse effects include decreased cardiac output.
• Treatments include digitalis, ibutilide, calcium channel blockers, beta-blockers, and oxygen.

Overview of atrial disorders, including premature atrial contraction, atrial tachycardia, flutter and fibrillation, and supraventricular tachycardia. Covers conduction patterns. Focuses on causes and intervals.