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.