Cardiac Back View: An Old Forgotten Echocardiographic Window.

Dear Sir,

In addition to the classical echocardiographic views, posterior approaches might allow to observe some structures better (descending aorta and posterior pericardium), especially in patients with pleural effusion. In fact, the left pleural effusion leads to pulmonary atelectasis and consequently, pulmonary anterosuperior displacement, creating a liquid space between the posterior wall of the chest and the heart that allows the transmission of the ultrasonic beam.[1] Posterior views are obtained with the patient in sitting position and the transducer placed in the left subscapular space. From here, the transducer can be moved more medially (paraspinal window) or laterally (posterior axillary window). The echocardiographic sections are like those of the parasternal or apical approach with the difference that the image appears inverted as in a mirror, displaying first the posterior walls [Video 1 and 2]. From subscapular or posterior axillary position, orienting the index mark to the right shoulder, we easily get a left parasternal long axis [Figure 1a]; rotating the transducer by 90°, we obtain a short-axis view of the ventricle [Figure 1b]. Slight movements of the transducer allow performing a 4-chamber view [Figure 1c]. From the paraspinal position, placing the ultrasound beam parallel to the vertebral spine, descending thoracic aorta appears [Figure 1d].[2] La Marchesina et al. described an interesting case report of descending aortic dissection in a patient with pleural effusion, diagnosed with the posterior echocardiographic approach[2] and showed that posterior views allow excellent differentiation of pericardial effusion versus pleural effusion, detection of pericardial disease and pericardial infiltration, and excellent endocardial border definition of left and right ventricles in those with poor anterior transthoracic windows.[3]

Figure 1

Posterior echocardiographic sections: parasternal long-axis view (a); posterior short-axis view (b); 4-chamber view (c); section for descending aorta (d). PE = Pleural effusion, LV = Left ventricle, RV = Right ventricle, RA = Right atrium, TA = Thoracic aorta

Subscapular retrocardiac imaging had been described in 1995 by Waggoner et al. previously, but in most actual echocardiography textbooks, it is not illustrated. And yet, especially in patients with pulmonary cancer, pleural effusion is certainly a frequent occurrence and these echocardiographic windows can allow analyzing the structures not visible from traditional windows. Although the benefits of this approach in the absence of pleural effusion are very limited, the use of posterior echocardiographic windows should be encouraged for its incremental diagnostic value, and for this reason, it should be described in the main echocardiography textbooks.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.