INTRODUCTION
Coronavirus disease 19 (COVID-19) pandemic has caused over 6 million deaths worldwide and these figures are likely underestimated1. COVID-19 infection may spam from asymptomatic or mild and self-limiting cases, to severe illness requiring hospitalization where COVID-19 may trigger a multi-systemic infection involving different organs2-5. The lungs seem the most affected organ with possible development of interstitial pneumonia requiring hospitalization and intensive care unit (ICU) admission with mechanical ventilation in severe cases6-8. A substantial cardiovascular impact in patients with COVID-19 has been repeatedly demonstrated9; of note, even patients not requiring hospitalization have shown some degree of myocardial dysfunction with features of myocarditis on magnetic resonance imaging10-13.
Severely ill COVID-19 patients admitted to ICU may experience cardio-circulatory failure and a fair amount of them may need support with catecholamine infusions. Different degrees of cardiac injury as evaluated by biomarkers14-16 or echocardiography9,17have been reported for COVID-19 patients admitted to ICU. Several patterns of cardiovascular dysfunction have also been described: from signs of myocarditis or myocardial ischemia to significant hypovolemia (due to pyrexia and prolonged fasting), from right ventricular (RV) failure (influenced by mechanical ventilation and/or by micro/macro pulmonary embolism) to septic cardiovascular dysfunction due to super-imposed bacterial or fungal infections10,11,13,18,19. Moreover, a combination of these features could be coexistent in severely ill patients with COVID-19. Interestingly, a gap of knowledge exists regarding the feasibility of precise characterization of left ventricular diastolic dysfunction (LVDD) according to the joint recommendations from the European Association of Cardiovascular Imaging (EACVI) and the American Society of Echocardiography (ASE)20 in this population of patients, which are at high risk for both chronic LVDD (i.e. history of hypertension and diabetes) or acute deterioration of their LV diastolic function. Of note, in non-COVID-19 critically ill patients, left ventricular diastolic dysfunction (LVDD) has received attention for its association with outcomes21-23, while the same association has not been shown for left ventricular systolic dysfunction (LVSD)24. Echocardiography is crucial in diagnosing and grading LVDD and may help distinguishing patterns of cardiovascular dysfunction, suggesting therapeutic options, and tracking the changes with sequential monitoring25.
Our single center joined the international ECHO-COVID study17. With the purpose to fully characterize LVDD, we also collected tissue Doppler Imaging (TDI) and left atrial volume index (LAVI) data. Hereby, we report the feasibility of full and simplified LVDD assessment in severe COVID-19 patients admitted to ICU, the incidence of LVDD and its association with mortality.