Left Atrial Appendage Thrombus in Low CHA2DS2VASc Score in Persistent Atrial Fibrillation

Atrial fibrillation is a commonly encountered arrhythmia, and its prevalence has increased over the years. Atrial fibrillation is the major cause of cardioembolic stroke, which is a debilitating complication of this arrhythmia. The most common site for this embolus is the left atrial appendage (LAA). CHA2DS2VASc score is the current scoring system that is used to stratify patients with atrial fibrillation on the risk of developing a stroke. Oral anticoagulants, either vitamin K antagonists or direct oral anticoagulants, are the treatment options in patients with a CHA2DS2VASc score of more than 2. Ironically, despite LAA being the most common site for thrombus formation, it is not included in this scoring system. Hence, patients with low CHA2DS2VASc scores still have a high risk of stroke with the presence of LAA thrombus alone. Herein, we report a case of a 51-year-old male individual who was diagnosed with atrial fibrillation-mediated cardiomyopathy complicated with LAA thrombus. An oral anticoagulant was not started during the initial diagnosis as his stroke risk was low based on the CHA2DS2VASc score. His score was 1. Incidentally, a huge LAA thrombus was detected before AF cardioversion for the rhythm control approach. Subsequently, he was managed using a direct oral anticoagulant and rhythm control approach. This case illustrates patients with low CHA2DS2VASc scores still can develop left atrial appendage thrombus, which could lead to a cardioembolic stroke. A careful assessment of stroke risk, including LAA thrombus risk assessment in patients with low CHA2DS2VASc scores is needed, to reduce the risk of thromboembolic stroke.