**2.2. Minor Duke echocardiographic findings**

Minor echocardiographic findings include but are not limited to perforation, valve aneurysm, fistula, pseudoaneurysm, valve leaflet destruction, and flail leaflet [2].

**Figure 8.** TEE color compare imaging of mitral valve vegetation with perforation (arrow) and severe regurgitation.

The first case report of TEE used to diagnose a perforation was published in 1991 [19]. A perforation is typically a defect through the valvular tissue, separate from the commissures and leaflet margins, well circumscribed and with a 'punched out' appearance on 3D imaging. The finding of a suspected perforation on 2D or 3D echo must be confirmed by demonstrating Doppler color flow traversing the body of the leaflet, typically characterized by flow convergence with a proximal isovelocity surface area (PISA) dome (**Figure 8**).

A valvular aneurysm occurs as a localized bulging sac of the valve leaflet tissue with pulsatile flow seen into the region during systole. The lesion most commonly involves the anterior mitral valve leaflet (AMVL) and usually arises secondary to aortic valve endocarditis [20, 21]. This occurs by either an infected aortic valve regurgitant jet 'seeding' the AMVL or alternatively, from contiguous spread along MAIVF. Localized infection of the mitral leaflet may be followed by valve aneurysm, perforation, and/or leaflet destruction [21].

Cardiac fistula is an uncommon, serious complication, occurring in <1–2.2% [22, 23] of patients with endocarditis and 6–9% of cases when abscess is present [22]. Fistulae often arise from the aortic root or the left ventricular outflow tract [24]. Aortic root fistulas form communications between the aorta and cardiac chambers (aortocavitary) and/or pericardial space (aortopericardial) and often result in hemodynamic compromise. Fistulas can also arise between cardiac chambers [25].

A pseudoaneurysm is defined on echocardiography as an echolucent space communicating with an adjacent cardiac chamber or with the aortic lumen. Blood enters into the cavity under pressure during systole and is seen as pulsatile flow on color Doppler imaging. Pseudoaneurysms frequently arise from the MAIVF with a communication to the left ventricular outflow tract through the narrow 'neck' of the aneurysmal sac [16]. Rupture of a pseudoaneurysm can result in a fistulous connection with the pericardial space, left atrium, or aortic lumen [16, 26].
