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