Discussion
The unequal distribution of race in our study likely reflects the demographics that our institute caters to. Although there have been reports that Hispanic and African American patients are disproportionately more effected and have worse outcomes. Hypertension and diabetes mellitus were the most common co morbidities in our patients associated with COVID-19 infection as seen in most of the previously published literature. Elevated brain natriuretic peptide (BNP) and cardiac troponin (cTr) have been associated with myocardial injury and poor outcomes. Inflammatory  biomarkers also play an important role in risk stratification of disease severity and prognostication. The prevalence of elevated biomarkers in our study was higher than the 8-12% observed by Lippi et al [2]. This was most likely the result of selection bias of  performing echocardiograms on the patients suspected to have cardiac injury. Other inflammatory biomarkers, like LDH , ferritin. and D-dimer suggesting were elevated in majority of our patients. These markers have been found to be associated with severe disease, hyper coagulation and increased mortality.
Myocarditis based on elevated troponins and inflammatory markers has been described previously [1] but no data on echocardiographic findings in these patients is available. The etiology of left ventricular dysfunction can be multifactorial in these patients. These patients can have acute myocardial infarction(AMI) due to plaque rupture secondary to stress of infection  as was seen in one of our patients who had complete occlusion on the mid left anterior descending artery and underwent percutaneous intervention. One patient in our study group developed stress related cardiomyopathy secondary to COVID-19 infection. He presented as cardiac arrest with minimal troponin elevation, echocardiogram was typical for takotsubo cardiomyopathy. Other possible etiologies for poor LV function in these patients could be myocarditis and prior LV dysfunction. Two echocardiograms were requested to rule LV thrombus as the patients presented with  acute limb ischemia but LV thrombus was not seen in any patients in our study including these two patients. The arterial thrombosis in these patients could result from coagulopathy secondary to disseminated intravascular coagulation, heparin-induced thrombocytopenia, thrombotic microangiopathy and antiphospholipid antibodies [3].
We had 2 patients with pulmonary embolism (PE) in our study group, echocardiogram guided diagnosis in these patients. There is a very high risk of thromboembolism including pulmonary embolism in patients with severe COVID-19 infection. Recently published data suggests incidence of thromboembolism as high 31% critically ill patients, pulmonary embolism was the most frequent (81%) thromboembolic complication in these patients [4]. In our study RV thrombus was visualized in one patient, which was confirmed on  computed tomography angiography (CTA) of the chest, showing diffuse pulmonary embolism. She was treated with low molecular weight heparin and repeat echocardiogram done 2 weeks later showed near complete resolution of thrombus.  The other patient with PE who was a 28 year old female with COVID -19 infection and no other risk factors, presented with severe shortness of breath was found to have CTA confirmed extensive bilateral pulmonary embolism after her echocardiogram showed RV dilatation with flattening of IVS. She received tissue plasminogen activator (tPA) and was eventually discharged home on apixaban. There is growing consensus that patients with COVID -19 infection have a prothrombotic state and development of microthrombi in pulmonary vasculature as demonstrated by pathological studies [5], this most likely could explain the elevated pulmonary pressures and RV dysfunction in these patients. Emerging evidence suggests that anticoagulation could help a selected group of patients[6], echocardiogram may act as an aid to identify these patients. Also hypoxemia and high positive end expiratory pressure ventilation requirement in these patients can lead to RV dysfunction and eventually poor cardiac output. Bedside echocardiogram in critical care units can help in identifying features of RV dysfunction and help in management of ventilators to minimize adverse effects on cardiac output.
In conclusion, 2-dimensional echocardiography can be an important bedside tool in assessment of  left and right ventricular function and hemodynamic status COVID-19 patients. When appropriately chosen for the correct group of patients echocardiogram can help in navigating management options and identifying complications.
Table 1 showing echocardiographic and laboratory parameters