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FAQs A-Fib Drug Therapy: Anticoagulant After Cardioversion
“After my cardioversion, my doctor kept me an anticoagulant for a month. Why is that required? They mentioned something about a “stunned atrium”. What is that?”
A “stunned atrium” is medically defined as a “state of temporary mechanical atrial dysfunction with preserved bioelectrical function.” In non-medical terms your heart doesn’t contract properly even though it is getting the right electrical and chemical signals to contract.
This can happen after an electrical cardioversion and is why the left atrium and, in particular, the Left Atrial Appendage tend to develop clots after an electrical cardioversion. The left atrium, and especially the Left Atrial Appendage, is “stunned” after the electrical shock and may not contract and pump out properly.
Clots can develop and be released when the LAA starts to contract again. That’s why you need to be on a blood thinner, an anticoagulant, for a month after your electrical cardioversion.
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Last updated: Wednesday, September 2, 2026
