A 44-year-old healthy woman presented with a first episode of recent onset atrial fibrillation (Panel A). Intravenous vernakalant was administered. Organization to atrial flutter with 2 : 1 atrioventricular conduction occurred (Panel B). After completion of the second infusion, the atrial cycle length prolonged slightly resulting in 1 : 1 atrioventricular conduction (Panel C). Immediate electrical cardioversion was performed. Diagnostic work-up did not reveal any structural or electrical pathology of the heart.
Vernakalant is a newer, relatively atrial-selective antiarrhythmic drug, designed to overcome the safety issues of the currently available drugs for cardioversion of atrial fibrillation. The conversion rate in recent onset atrial fibrillation is reported to be ∼50%. Compared with other antiarrhythmic drugs, vernakalant was not associated with rapid conducted atrial flutter or serious ventricular arrhythmias. The guidelines recommend vernakalant for cardioversion of recent onset atrial fibrillation in patients with no or minimal structural heart disease and with some restrictions in patients with moderate heart disease.
This case describes the occurrence of atrial flutter with 1 : 1 atrioventricular conduction after administration of vernakalant for atrial fibrillation in a patient with a structural normal heart and no evidence of pre-existing arrhythmias. Therefore, despite the low pro-arrhythmic risk, careful patient monitoring is necessary when using vernakalant.
The full-length version of this report can be viewed at: http://www.escardio.org/communities/EHRA/publications/ep-case-reports/Documents/atrial-flutter-with-atrioventricular.pdf.
