There are still many gaps in our knowledge regarding the direct cardiovascular injuries due to COVID-19 infection. In this study, we tried to find out the effect of SARS-CoV-2 infection on cardiac function in patients without any history of structural heart disease by electrocardiographic and echocardiographic evaluations. This was a cross-sectional study on patients with COVID-19 infection admitted to Imam Reza hospital, Mashhad, Iran between 14 April and 21 September 2020. COVID-19 infection was verified by a positive reverse-transcriptase polymerase chain reaction (PCR) assay for SARS-CoV-2 using nasopharyngeal/oropharyngeal samples. We enrolled all patients over 18 years old with definite diagnosis of COVID-19 infection. All patients underwent a comprehensive transthoracic echocardiography at the first week of admission. Clinical and imaging data were collected prospectively. In total, 142 patients were enrolled in this study. The mean age of participants was 60.69 ± 15.70 years (range: 30–90 years). Most patients were male (82, 57.7%). Multivariate analysis showed that O2 saturation at admission was independently a predictor of re-hospitalization (P < 0.001). RV size (P < 0.001), dyslipidemia (P < 0.001), ejection fraction (EF) (P < 0.001), age (P = 0.020), systolic blood pressure (P = 0.001), O2 saturation (P = 0.018) and diabetes (P = 0.025) independently predicted 30-days mortality. Echocardiography can be used for risk assessment in patients with COVID-19, especially in those with previous history of diabetes and dyslipidemia. The infection could result in ventricular dysfunction, even in those without previous history of structural heart disease.