The researchers conclude that waiting more than 6 months for cardioversion is associated with a significantly reduced chance of remaining in sinus rhythm over the long term. They also observed that having an enlarged left atrium, as well as having had a prevision cardioversion, markedly reduced the chance of a successful long-term outcome. Thus, the combination of AF duration more than 6 months, an enlarged left atrium, and a previous ECV reduced 5-year success rate to 13%.
During the first 30 days after the ECV, one 79-year-old woman (CHA2DS2-VASc score of 8) suffered a stroke and one 78-year-old man (CHA2DS2-VASc score of 7) suffered a TIA (transient ischemic attack). Both were on warfarin within therapeutic range (INR of 2.41 and 2.63 respectively) at the time of their event. A total of 13 symptomatic ischemic events (mainly strokes and TIAs) occurred during the entire follow-up – all in patients having a CHA2DS2-VASc score greater than 2.
The researchers conclude that properly conducted ECV is associated with a high acute success rate and low complication rates. However, long-term success declines dramatically in patients having been in persistent AF for more than 6 months prior to their cardioversion.
Toso, E, et al. Electrical cardioversion of persistent atrial fibrillation: acute and long-term results stratified according to arrhythmia duration. PACE, Vol. 35, September 2012, pp. 1126-34