Final answer:
A TEE is usually performed before DC cardioversion if atrial fibrillation or flutter has been present for more than 48 hours or when the duration is unknown, to rule out thrombi and prevent stroke. Anticoagulants are given if TEE is not performed, to mitigate risks.
Step-by-step explanation:
In the context of direct-current (DC) cardioversion, a transesophageal echocardiogram (TEE) is not mandatory before the procedure if the patient has been in atrial fibrillation or atrial flutter for less than 48 hours and has been adequately anticoagulated. However, if atrial fibrillation or flutter has been present for more than 48 hours or the duration is unknown, a TEE is often performed to rule out the presence of atrial thrombi (blood clots) which could increase the risk of stroke if dislodged during the cardioversion. The goal of this imaging procedure is to minimize the risk of thromboembolic events post-cardioversion.
Using a transesophageal echocardiogram (TEE) provides a detailed visualization of the heart's chambers and can detect clots that might not be visible through a transthoracic echocardiogram (TTE). Anticoagulants such as blood thinners are usually administered for several weeks before DC cardioversion if TEE is not performed, to reduce the risk of complications.