On this page:

• Definition
• Causes & Patho-physiology
• Implications
• Treatment

Definition

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Causes & Patho-physiology

• In atrial fibrillation, the atria are stimulated to contract very rapidly in an unco-ordinated manner which is different from the normal activity originating from the sinoatrial node. This results in ineffective and unco-ordinated contraction of the atria.

• In atrial flutter, this pattern of contraction is in the form of a peculiarly organized rhythm.

• This condition can be caused by irregular impulses which are transmitted to the ventricles. Some of these irregular impulses may even fail to be transmitted. This makes the ventricles to beat irregularly, rapidly or too slowly failing to pump enough blood to meet the body's needs.

• In atrial flutter however, the ventricles may beat rapidly, but in a regular pattern.

• Underlying causes of atrial fibrillation and flutter include dysfunction of the sinus node which is the "natural pacemaker" of the heart.

• A number of heart and lung disorders like coronary artery disease, rheumatic heart disease, mitral valve disorders and pericarditis can also cause atrial fibrillation.

• Hyperthyroidism, hypertension, recent heavy alcohol use can cause atrial fibrillation/flutter and other arrhythmias.

• Some cases of atrial fibrillation or flutter occur in the setting of a heart attack (myocardial infarction) or soon after a heart surgery.

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Implications

A pulse that is too rapid or too slow may reduce the amount of blood the heart can pump and lead to syncope (fainting). Emboli to the brain (stroke) or elsewhere may rarely occur but can often be treated with anticoagulation to reduce this risk.

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Treatment

• Emergency Treatment
  To convert the arrhythmia to normal (sinus) rhythm, either with electrical cardioversion or with the administration of intravenous drugs, such as dofetilide or ibutilide.
• Long-term Treatment may vary depending on the cause of the atrial fibrillation or flutter.
  • Medication for long term use may include beta-blockers, calcium channel blockers, digitalis or other medications such as antiarrhythmic agents which slow the heartbeat or slow the conduction of the impulse from the atria to the ventricles. Medications may also include blood thinners, such as heparin or coumadin, to reduce the risk of thromboemboli resulting in stroke.

  • Radio-frequency Ablation - Some patients with atrial fibrillation who have rapid heart rates and intolerance to medication may require a catheter procedure on the atria called radiofrequency ablation. For most patients with atrial flutter, radiofrequency ablation is the current treatment of choice. Some patients with atrial fibrillation and rapid heart rates may need the radiofrequency ablation done directly on the AV junction. Ablation of the AV junction leads to complete heart block. These patients then require a permanent pacemaker.

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