Prevention of Atrial Fibrillation Following Noncardiac Thoracic Surgery

Thousands of patients undergo major non-cardiac open-chest surgery in the United States each year. These surgeries most often consist of lung surgery, in which one lobe of the lung is removed (lobectomy) or the entire lung is removed (pneumonectomy).

A major complication of these non-cardiac open-chest surgeries is the occurrence of an irregular heartbeat known as atrial fibrillation (AF), which develops in up to 40% of patients undergoing these procedures. AF is characterized by rapid, irregular, chaotic beating of the two smaller chambers of the heart (the atria), leading to rapid, irregular beating of the two larger chambers (the ventricles). The average time to occurrence of post-surgical AF is 2-3 days following surgery. AF occurring following major non-cardiac open-chest surgery can result in extremely rapid heart rates, as fast as 150-200 beats per minute, and may be associated with serious consequences, including severely low blood pressure and potentially debilitating stroke. Further, the risk of death following non-cardiac open-chest surgery is significantly higher in patients who develop AF compared with those who do not. Therefore, the occurrence of this irregular heartbeat following non-cardiac open-chest surgery is associated with severe, potentially life-threatening consequences. Prevention of this irregular heartbeat in these patients may therefore be very important.

Amiodarone is a medication that is known to be effective for prevention and treatment of AF that occurs in patients who have not undergone surgery. In addition, amiodarone has been shown to be effective for prevention of AF following open-chest heart surgery. However, the use of medications for prevention of AF following non-cardiac open-chest surgery has not been well studied, and amiodarone has not been studied in a controlled trial for the prevention of AF in patients undergoing these procedures. In addition, amiodarone is associated with side effects, and it is important to determine the safety of this medication when used in this patient population.

Inclusion criteria

• Males or females over the age of 40
• Scheduled to undergo pneumonectomy or lobectomy

Exclusion criteria

• History (hx) of atrial fibrillation
• Prior severe side effects from amiodarone
• Elevated liver enzymes >3 times the upper limit of normal (UNL)
• QTc interval > 450 ms
• Receiving class Ia or class III antiarrhythmics