Epicardial Echocardiography-A Plausible Alternative Cardiac Imaging Technique in COVID-19 Pandemic.

To the Editor:

Coronavirus disease 2019 (COVID-19), because of its high infectivity rate, created havoc across the globe. Healthcare workers are the most affected community, having high mortality across the world. Severe acute respiratory syndrome coronavirus 2 enters cells through angiotensin- converting enzyme-2 receptors, which are expressed mostly in lung and intestines. So, the virus load is increased in aerodigestive tract secretions. Any procedure involving the aerodigestive tract causes aerosolization, which increases the risk of direct and cross-contamination among healthcare workers. Transesophageal echocardiography (TEE), being an aerodigestive tract procedure, commonly is used in cardiac surgery to evaluate the heart and its associated structures.

Even though various techniques and maneuvers are suggested in recent literature to reduce aerosolization during TEE usage, the risk of infection still persists. The TEE probe remains in contact with the aerodigestive tract secretions, posing a potential contamination risk to healthcare workers handling the TEE probe for imaging as well as during disinfection. Usage of a protective sleeve over the TEE probe may not avoid the virus exposure completely. Moreover, a protective sleeve over the TEE probe makes the maneuver of the probe more difficult to acquire images and also compromises the image quality. Hence, the American Society of Echocardiography recommends an alternate method for TEE to be used whenever possible in COVID-19 patients.

Epicardial echocardiography (E-echo) is not an uncommon imaging modality in perioperative cardiac settings. E-echo is well known to produce high-quality images, especially of the anterior cardiac structures compared to TEE.6, 7, 8 In addition to it, epiaortic echocardiography gives more valuable information about aortic diseases perioperatively. E-echo can be performed easily by using a transthoracic probe or TEE probe (Fig 1 -3 ).

Fig 1

Echo probe covered with sterile sleeve placed over epicardium.

Fig 3

Epicardial left ventricular basal short-axis view. RV, right ventricle; AML, anterior mitral leaflet; PML, posterior mitral leaflet.

Epicardial left ventricular long-axis view. RVOT, right ventricular outflow tract; LVOT, left ventricular outflow tract; LA, left atrium.

Advantages of E-echo and epiaortic echocardiography over TEE in the midst of COVID-19 pandemic are as follows:

There is no aerosolization with E-echo/epiaortic echocardiography.

Usually, E-echo has been performed with a protective cover over the probe, which eliminates the direct contact of the probe with patients' body fluids. Thus, decontamination of the probe is simple and easy to perform. Further, it reduces the virus exposure to healthcare workers significantly compared to TEE.

Except for a transparent cover over the echocardiography machine while using it for suspected/confirmed COVID-19 cases, no special preparation is needed. So, there is no significant change in image quality.

Limitations of E-echo over TEE are as follows:

Hemodynamic and rhythm disturbances can occur due to direct cardiac compression. However, it is minimal on the adult heart and can be avoided by gentle probe handling.

Infection risks cannot be neglected, which can be minimized by sterile handling and reducing the examination duration.

Apical views are not possible due to space constraints while using a standard epicardial probe, which can be overcome by using a TEE probe.

E-echo may cause distraction for the surgeon, leading to prolongation of surgery.

Although TEE supplanted E-echo in cardiac surgery, the COVID-19 pandemic mandates us to search for an alternative option to TEE in intraoperative cardiac imaging. Thus, E-echo can be a viable alternative to TEE during this COVID-19 pandemic.