Atrial fibrillation

Atrial fibrillation;

 

Guide to rate control

 

• Digoxin is ineffective in controlling ventricular rate during acute episodes and    paroxysmal episodes and in states with high sympathetic tone such as

Thyrotoxicosis, critical illness, and postoperative states.

Digoxin is also ineffective for cardioversion

 

• In patients with good left ventricular function, beta blockers (metoprolol, propranolol, and atenolol) or non-dihydropyridine calcium antagonists (verapamil and diltiazem) are the drugs of choice, provided no contraindications exist

 

• In patients with acute or chronic heart failure, digoxin or Amiodarone should be used.

The chronic use of amiodarone is limited by its side effects.

Beta blockers may be considered in patients with stable heart failure

 

• Although digoxin does not provide good rate control in acute episodes, it is generally effective for rate control in persistent atrial fibrillation when used

in combination with beta  blockers and rate limiting calcium antagonists

 

• The adequacy of rate control should be assessed by the clinical symptoms

 

• Target heart rates vary with age. They should generally be 60-90 beats per minutes at rest and 90-115 beats per minute during exercise. This requires

careful dose titration

 

• Poor ventricular rate control in the long term leads to a reversible deterioration of left ventricular function (tachycardiomyopathy)

 

 

Guide to rhythm control

 

• Identify and treat all reversible causes of atrial fibrillation before considering drug treatment for maintenance of sinus rhythm.

Pharmacological cardioversion is effective when initiated within 7 days of the onset of arrhythmia.

 

• The selection of antiarrhythmic drug needs to be tailored individually to the patient, depending on cardiac status, comorbidities, and contraindications.

With the potential side effect of antiarrhythmic drugs, pharmacological cardioversion should be reserved for haemodynamically stable patients with symptoms.

 

• In patients with good left ventricular function and no coronary artery disease, flecainide and propafenone can be used.

Sotalol or amiodarone can also be used in such patients.

 

• Amiodarone can be used to maintain sinus rhythm in patients with heart failure. Although not currently licensed in the United Kingdom, dofetilide is an

Alternative.

 

• Beta blockers are the drugs of choice for patients with coronary artery disease.

 

• If sinus rhythm cannot be maintained despite repeated cardioversions and antiarrhythmic treatment, a “rate control” strategy should be adopted. This has

been shown to be as effective as rhythm control.

 

• Patients who find the symptoms of the arrhythmia unacceptable despite rate control may be considered for non-pharmacological methods to restore sinus rhythm.

 

• Electrical cardioversion is a save procedure with success rate of 70-90%.

  It is used acutely in patients who are haemodynamically compromised or electively as alternative to pharmacological cardioversion.