Biological cardiac injury related to the Severe Acute Respiratory Syndrome Coronavirus-2 infection has been associated with excess mortality. However, its functional impact remains unknown. The aim of our study was to explore the impact of biological cardiac injury on myocardial functions in patients with COVID-19. 31 patients with confirmed COVID-19 (CoV+) and 16 controls (CoV−) were prospectively included in this observational study. Demographic data, laboratory findings, comorbidities, treatments and myocardial function assessed by transthoracic echocardiography were collected and analysed in CoV+ with (TnT+) and without (TnT−) elevation of troponin T levels and compared with CoV−. Among CoV+, 13 (42%) exhibited myocardial injury. CoV+/TnT + patients were older, had lower diastolic arterial pressure and were more likely to have hypertension and chronic renal failure compared with CoV+/TnT−. The control group was comparable except for an absence of biological inflammatory syndrome. Left ventricular ejection fraction and global longitudinal strain were not different among the three groups. There was a trend of decreased myocardial work and increased peak systolic tricuspid annular velocity between the CoV− and CoV + patients, which became significant when comparing CoV− and CoV+/TnT+ (2167 ± 359 vs. 1774 ± 521%/mmHg, P = 0.047 and 14 ± 3 vs. 16 ± 3 cm/s, P = 0.037, respectively). There was a decrease of global work efficiency from CoV− (96 ± 2%) to CoV+/TnT− (94 ± 4%) and then CoV+/TnT+ (93 ± 3%, P = 0.042). In conclusion, biological myocardial injury in COVID 19 has low functional impact on left ventricular systolic function. Keywords COVID-19 • SARS-CoV-2 • Speckle tracking echocardiography • Strain • Myocardial work. Abbreviations CT Computed tomography hs-TnT High-sensitivity troponin T IQR Interquartile ranges LS Longitudinal strain TTE Transthoracic echocardiography RT-PCR Real-time reverse transcriptase-polymerase chain reaction SARS-CoV-2 Severe acute respiratory syndrome coronavirus-2 TAPSE Tricuspid annular plane systolic excursion