Related Experiment Video
Updated: Mar 22, 2026
The WATCHMAN Left Atrial Appendage Closure Device for Atrial Fibrillation
Published on: February 28, 2012
A Stunning Left Atrial Appendage Thrombus
Sajid Ali1, Justin Ugwu, Yousuf Kanjwal
1Mercy St. Vincent Hospital and Medical Center, Toledo, Ohio, USA.
Insights
Acute left atrial appendage thrombus formation can occur immediately after atrial flutter ablation. This highlights the importance of continuing anticoagulation therapy during and after arrhythmia conversion to prevent stroke risk.
Area of Science:
- Cardiology
- Electrophysiology
- Vascular Medicine
Background:
- Left atrial appendage (LAA) thrombus formation is a significant complication of atrial fibrillation and flutter, increasing embolism and stroke risk.
- This thrombosis risk is exacerbated by interrupted anticoagulation.
- Atrial myocardial stunning, a persistent risk of thrombus formation post-arrhythmia conversion, is a known phenomenon.
Observation:
- A patient undergoing atrial flutter ablation developed a large LAA thrombus immediately after successful cavotricuspid isthmus ablation.
- The thrombus was not present on pre-ablation transesophageal echocardiography.
- This occurred despite successful restoration of sinus rhythm.
Findings:
- This case demonstrates acute LAA thrombus formation occurring immediately following successful atrial flutter ablation.
- Atrial stunning can lead to rapid thrombus development even after successful rhythm conversion.
- The timing of thrombus formation post-ablation is faster than previously documented.
Implications:
- Anticoagulation should not be interrupted prior to or during procedures aimed at converting atrial arrhythmias to sinus rhythm.
- This finding underscores the need for careful monitoring of LAA thrombus risk in patients undergoing ablation.
- Strategies for managing anticoagulation in patients with atrial arrhythmias require reassessment to mitigate acute thrombotic events.
Background:
Left atrial appendage thrombus formation is a known major complication of atrial fibrillation and atrial flutter which increases the risk of embolism and stroke. This risk of thrombosis is greatly increased with a lack of anticoagulation. After conversion to a normal sinus rhythm in these arrhythmias, the risk of thrombus formation in the left atrium persists through a phenomenon termed atrial myocardial stunning.
Case:
We present the case of a patient who previously underwent successful pulmonary vein isolation and was found to be in typical isthmus-dependent atrial flutter with a questionable recurrence of atrial fibrillation. The decision was made to return for atrial flutter ablation and for evaluation of prior pulmonary vein isolation. Initially, a transesophageal echocardiogram showed a normal ejection fraction, biatrial enlargement and no left atrial appendage thrombus. Ablation of the cavotricuspid isthmus was successfully accomplished with documented bidirectional block. A transesophageal echocardiogram probe was still in place prior to planned transseptal puncture for the evaluation of pulmonary veins. A large thrombus was now observed filling the left atrial appendage. Conclusion and Objective: Atrial stunning is a transient atrial contractile dysfunction that occurs whether sinus rhythm is restored spontaneously, electrically, pharmacologically or by ablation. We know after conversion that there is higher propensity to increased spontaneous echogenic contrast and decreased velocities; however, we do not have documented knowledge of exactly how soon after the conversion to a sinus rhythm a thrombus may be seen. We demonstrate a case of acute left atrial appendage thrombus formation immediately following the successful ablation of isthmus-dependent atrial flutter. Our report validates the belief that strategies of not interrupting anticoagulation prior to the conversion of these arrhythmias should be implemented.
