The results of a new study published in The Lancet show that pharmacological cardioversion is as safe and effective for resolving acute atrial fibrillation (AF, AFib) as electrical cardioversion.
Acute AF accounts for about 430,000 emergency department (ED) visits in the United States and Canada each year. To avoid complications, such as stroke and heart failure, patients with acute AF must receive treatment within 48 hours. ED doctors and hospitalists in the U.S., Canada, and other countries use electrical and pharmacological cardioversion to restore normal heart rhythms.
“These methods allow us to quickly get patients back to their normal heart rate, and send them home after four to six hours in the emergency department,” said Dr. Ian Stiell, lead author and senior scientist at The Ottawa Hospital and distinguished professor at the University of Ottawa.
Electrical Versus Pharmacological Cardioversion in the ED
The researchers enrolled 396 patients with acute AF from 11 Canadian EDs, and randomly assigned the participants into two groups. The first group of 192 participants received only electrical cardioversion, along with sedation. The 204 participants in the second group received IV procainamide; these patients received electrical cardioversion only if the IV drug did not bring the participant out of AF.
Ninety-two percent of those in the shock-only group returned to normal sinus rhythm and 95% were discharged home. Of the participants in the drug-shock group, 96% returned to normal heart rhythm and 97% were discharged home.
The researchers in this large, randomized controlled trial found that both electrical and pharmacological cardioversion were equally as good at restoring sinus rhythm and getting patients home the same day. The team of scientists also found that that drug-shock strategy was more effective for patients who were experiencing AF for the first time, and for those under the age of 70.
The two methods of cardioversion proved to be equally as safe, as none of the patients from either group experienced any serious side effects. In fact, in the two weeks following cardioversion, 95% of all the participants had normal heart rhythm, none had had a stroke, 11% returned to the ED for AFib, 3% underwent an additional round of cardioversion, and 2% were admitted to the hospital.
More than half of the patients receiving pharmacological cardioversion did not require electrical cardioversion to restore sinus rhythm. The authors of the study recommend that, to avoid unnecessary sedation, physicians should try pharmacological cardioversion first.
“If I have a patient on a drug infusion, I can see other patients at the same time,” said study co-author, Dr. Jeffrey Perry. “To do an electrical cardioversion, I need to find another doctor, a nurse and a respiratory therapist, and it takes time to assemble those people.”
While there are advantages to trying pharmacological cardioversion first, the choice between shock and drug infusion is ultimately up to the patient and physician. Many patients, especially those who need cardioversion regularly, often have a strong preference for one type of cardioversion over the other. It may also depend on location, as cardioversion is common in the United States and Canada, but not necessarily in other parts of the world.
“In some countries, patients with acute atrial fibrillation are sent home with pills to slow their heart rate, while others are admitted to hospital,” said Dr. Stiell. “Our study showed that cardioversion in the emergency department is safe and effective. We hope our results convince more physicians around the world to adopt these methods.”
