Symptoms of uncontrolled atrial fibrillation include palpitations and poor cardiac performance, with resultant worsening of coronary artery disease, congestive heart failure and possible sudden death. Patients presenting with new-onset atrial fibrillation are usually admitted to the hospital for evaluation of cardiac pathology and to monitor for complications. Anti-arrhythmic therapy may require extended cardiac monitoring because of proarrhythmic complications. Cardioversion is generally safe if patients present within 48 hours of the start of atrial fibrillation. With a longer duration of symptoms, patients should undergo three weeks of anticoagulation therapy before cardioversion is attempted. Recently, the need for hospitalization in low-risk patients with new-onset atrial fibrillation has been questioned. Michael and associates reviewed the postcardioversion management of low-risk patients who presented with symptoms of atrial fibrillation lasting for less than 48 hours.
During the 18-month study period, 168 low-risk patients made 289 visits to the emergency department. Atrial fibrillation was one of the discharge diagnoses in all of the study subjects. The average age of the participants was 64 years. Seventy-two percent had a previous history of atrial fibrillation.
Seventy-five percent of the patients who received medication to control heart rate had a rate reduction to less than 120 beats per minute, with diltiazem providing the highest rate of success and adenosine and digoxin being least helpful. Ninety of 180 attempts at chemical cardioversion were successful. Intravenous procainamide was used in 98 percent of these cases. Ninety-nine percent of the patients who had a successful chemical cardioversion were discharged home from the emergency department. Eighty patients underwent electric cardioversion; in most of these patients, chemical cardioversion had failed. Patients who were successfully converted were discharged home. Ten percent of patients unexpectedly returned to the emergency department within seven days, although none of the patients had complications associated with cardioversion.
The authors conclude that, assuming patients presenting with new-onset atrial fibrillation are at low risk, most patients (97 percent) treated in the emergency department with either heart rate control, chemical cardioversion or electric cardioversion do not require hospitalization. Rates of short-term complications appear to be very low, but long-term complications require further study.