Coronary flow reserve is the capacity of the coronary circulation to augment the blood flow in response an increase in myocardial metabolic demands and has a powerful prognostic significance in different clinical situations. It might assess with invasive and non-invasive technique. Transthoracic echocardiography Doppler is an emerging diagnostic technique, noninvasive, highly feasible, safe for patient and physician, without radiation, able to detect macrovascular and microvascular anomalies in the coronary circulation. This review aims to describe the benefit and limits of noninvasive assessment of coronary flow reserve, in particular his evaluation with echocardiography.

Information on atrial arrhythmias in patients with COVID-19 pneumonia is limited, and we aimed to explore the possible association of left atrial (LA) involvement and of atrial fibrillation (AF) occurrence with mortality in patients with COVID-19 pneumonia. A total of 140 hospitalized patients with COVID-19 pneumonia were included in the analysis; mean age was 66.6 years (range, 20-89 years), and 56 (40%) were female. A total of 35 patients had cardiac injury (increased troponin levels), and these patients were older, had more frequently systemic hypertension, had higher levels of C-reactive protein and of D-Dimer, and a higher proportion of multiple ground-glass opacities in computed tomography findings. By echocardiography, LA diameters and volume index (LAVI) injury (33.9± 27.2±8.7 ml/m2; P<0.001) were significantly increased in patients with cardiac. Greater proportion of patients with cardiac injury showed AF occurrence (14 of 35 [40.0%] vs 11 of 105 [10.4%]; P < 0.0001). Patients with cardiac injury had higher mortality than those without cardiac injury (17 of 35 [48.5 %] vs 9 of 105 [8.5%]; P < 0.0001). In a Cox regression model, in the overall population of COVID pneumonia patients, troponin levels (Hazard Ratio, 4.29 [95% CI, 1.85-8.43] P< 0.001), LA volume index (HR 3.6 [95% CI, 1.15‒7.48; p<0.001], PASP (HR: 3.9; [95% CI, 1.72-6.39] P< 0.001) and AF occurrence (HR: 2.5; [95% CI, 1.22-5.4] P< 0.001) emerged as independent predictors of in-hospital death. Assessment of both LA morphology and function during the recovery of COVID patients with cardiac injury may represent key points in the prognostic stratification

Purpose: This study was a quality-control study of resting and exercise echocardiography (EDE) variables measured by 19 echocardiography laboratories with proven experience participating in the RIGHT Heart International NETwork. Methods: All participating investigators reported the requested variables from ten randomly selected exercise stress tests. Intraclass correlation coefficients (ICC) were calculated to evaluate the inter-observer agreement with the core laboratory. Inter-observer variability of resting and peak exercise tricuspid regurgitation velocity (TRV), right ventricular outflow tract acceleration time (RVOT Act), tricuspid annular plane systolic excursion (TAPSE), tissue Doppler tricuspid lateral annular systolic velocity (S’), right ventricular fractional area change (RV FAC), left ventricular outflow tract velocity time integral (LVOT VTI), mitral inflow pulsed wave Doppler velocity (E), diastolic mitral annular velocity by TDI (e’) and left ventricular ejection fraction (LVEF) was measured. Results: The accuracy of 19 investigators for all variables ranged from 99.7% to 100%. ICC was > 0.80 for all observers. Inter-observer variability for resting and exercise variables was for TRV = 3.8 to 2.4%, E = 5.7 to 8.3%, e’ = 6 to 6.5%, RVOT Act = 9.7 to 12, LVOT VTI = 7.4 to 9.6%, S’= 2.9 to 2.9% and TAPSE = 5.3 to 8%. Moderate inter-observer variability was found for resting and peak exercise RV FAC (15 to 16%). LVEF revealed lower resting and peak exercise variability of 7.6 and 9%. Conclusions: When performed in expert centers EDE is a reproducible tool for the assessment of the right heart and the pulmonary circulation