2.2. Definition for NOAF
The NOAF group consisted of patients who had all of the following criteria: first AF attack after hospitalization for COVID-19, NOAF attack continuing for at least one hour, and need for medical and/or electrical cardioversion. 12-derivation electrocardiography (ECG) record is routinely obtained from all patients at the time of admission to the ICU in our center (number of beds = 30). All beds are monitored in the ICU, and nurse to bed ratio was 1/2. When there was either monitor image/alarm or examination findings that are compatible with AF, an immediate 12-derivation ECG was recorded and the intensivist and/or cardiologist confirmed the definite NOAF diagnosis. The treatment, medical and/or electrical cardioversion, was decided according to the clinical condition of the patient.