Both drug and shock cardioversion effective, safe for acute afib in the ED

By Marilynn Larkin

NEW YORK (Reuters Health) - 5/2/2020

In patients with acute atrial fibrillation in the emergency department (ED), normal heart rhythm can be safely restored either by immediate electrical cardioversion or by first attempting pharmacological cardioversion, followed by electric shocks if necessary, researchers say.

"While I prefer the drug-shock option, as it uses fewer resources and works half of the time, ultimately I am in favor of letting patients determine which of these two effective strategies they would prefer," Dr. Jeffrey Perry of University of Ottawa told Reuters Health by email.

Dr. Perry and colleagues at 11 academic EDs in Canada randomly assigned 396 patients (mean age, 30; 66% men) to attempted cardioversion with IV procainamide (15 mg/kg over 30 min) followed by electrical cardioversion if needed (up to three shocks of 200 joules or more), or a placebo infusion followed by electrical cardioversion.

Patients receiving electrical cardioversion were then randomly assigned to anteroposterior versus anterolateral pad positions. Randomization occurred 30 minutes after drug infusion for patients who had not converted.

As reported in The Lancet, sinus rhythm was restored in 96% of the drug-shock group and 92% of the shock-only group; 52% of patients in the drug-shock group converted after drug infusion only.

The different pad positions yielded similar conversions to sinus rhythm: 94% in the anterolateral group versus 92% in anteroposterior group.

The proportion of patients discharged home was 97% versus 95%. No serious adverse events occurred during follow-up. Two weeks after treatment, no patients had had a stroke, 95% still had normal heart rhythm, 11% returned to the ED because of atrial fibrillation, 3% had an additional round of cardioversion, and 2% were admitted to hospital.

Summing up, the authors state, "Both the drug-shock and shock-only strategies were highly effective, rapid, and safe in restoring sinus rhythm for patients in the emergency department with acute atrial fibrillation, avoiding the need for return to hospital."

Dr. Perry said, "Very few studies have compared different antiarrhythmic agents head-to-head for recent onset atrial fibrillation to determine the optimal pharmacologic treatment. Further study could compare different pharmacological treatment options."

Drs. Giorgio Costantino and Monica Solbiati of the University of Milan, coauthors of a related editorial, commented in an email to Reuters Health, "This study addresses a very important aspect of the management of atrial fibrillation in the ED."

"Some studies show that a high percentage of patients spontaneously convert to sinus rhythm. Therefore, some patients can be referred for an outpatient evaluation in the next 24 hours for the decision of cardioversion," they said. However, organizing this "can be difficult, and (is) not possible in many settings."

"The results of this study support the importance of a shared decision making with the patients on how to handle acute atrial fibrillation," they noted.

All available strategies have strengths and weaknesses, they said. "Electrical cardioversion is highly effective, rapid, there is no need for antiarrhythmic drugs and it is safe in patients with structural heart disease. However, there is need for sedation, which can be time-consuming and risky in some subsets of patients."

Pharmacologic cardioversion doesn't require sedation, they said, but it has a lower success rate, may induce arrhythmia or side effects, and may be contraindicated in structural heart disease.

"The wait-and-see approach has high rates of spontaneous cardioversion and there is no need for antiarrhythmic drugs or sedation," they said. But prompt follow-up care and high patient compliance are needed.

Ultimately, they conclude, the management strategy should be shared between the physician and the patient, and tailored to the patient's characteristics and preferences.


The Lancet, online February 1, 2020.

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