If a punctate strong echogenicity of the left atrium is found, it is usually most commonly associated clinically with left atrial thrombosis. Of course, a transesophageal echocardiogram may be required to further clarify whether the echo is a thrombus or some other problem. The most common cause of left atrial thrombus formation is atrial arrhythmias, such as atrial flutter and atrial fibrillation. Since atrial arrhythmias occur, the atria beat irregularly, the blood flow in the atria is disturbed, and even a series of conditions such as vortex may occur. Therefore, in this case, due to the special location of the left auricle, there is a possibility that a thrombus may form in the comb muscle. If the thrombus is dislodged, it will follow the blood flow and reach various places in the body, for example, brain embolism may occur if it falls on the head, and brain infarction may occur clinically, and peripheral artery embolism may be easily caused if it falls on the peripheral artery. Therefore, if an atrial punctate strong echo is found, it must be further examined to clarify whether it is a thrombus. If it is a thrombus, antithrombotic treatment must be taken to dissolve the thrombus. Otherwise, the thrombus will be dislodged and cause peripheral embolism, resulting in serious consequences.