Background: The first surge of coronavirus disease 2019 (COVID-19) cases in Bulgaria occurred in the fall of 2020. Here we describe the clinical presentation, patient characteristics, treatments and outcomes of mechanically ventilated COVID-19 patients in a newly formed COVID-19 ICU at a tertiary cardiac center in Sofia, Bulgaria. Methods: This is a retrospective observational study of mechanically ventilated COVID-19 patients admitted to Sveta Ekaterina University Hospital in Sofia, Bulgaria, between November 4th, 2020 and January 6th, 2021. Data were collected from electronic and written patient records and charts. Results: We identified 38 critical care patients admitted with respiratory failure and treated with mechanical ventilation at our COVID-19 ICU during this period. The median age was 66 (IQR 57-76, range 27-89) and 74% were male. Most patients, 36 (95%), had at least one comorbidity. The most common comorbidities were hypertension, valvular heart disease, ischemic heart disease and diabetes mellitus. Overall, 27 (71%) patients had a concomitant cardiac disease other than hypertension and 24% were recent cardiac surgical patients. Inotropic support was required in 29 (76%) patients, renal replacement therapy in 12 (32%) patients and prone positioning and ECMO were used in 5 (13%) and 2 (5%) patients respectively. The median duration of mechanical ventilation was 7.5 (IQR 5-14) days overall and 9 (IQR 6-13) days for survivors. At 30-days 28 (74%) of patients had died. Overall, 32 (84%) patients died in hospital and only 6 (16%) patients were discharged home. Conclusions: During the first major surge of COVID-19 cases in Bulgaria, despite the wave arriving later than in other countries, the healthcare system was largely unprepared. In our setting, mortality in mechanically ventilated patients was very high at 84%. Several factors might have contributed to these results, namely the predominance of cardiovascular comorbidities in our patient population, the strained ICU capacity and the lack of medical personnel.