Introduction: Use of mobile cardiac outpatient monitor (MCOT) increased during the COVID-19 pandemic as a substitute for telemetry and monitoring of arrythmias during loading of antiarrhythmic drugs (AAD). However, data comparing difference of QTc interval between a MCOT, and 12 lead ECG is scare. Hypothesis: To assess the accuracy of mobile cardiac outpatient monitor in comparison to 12 lead ECG for QTc monitoring Methods: We prospectively evaluated 24 patients at our institution who received IV sotalol as single day loading dose for initiation of oral sotalol therapy for atrial fibrillation/atrial flutter (AF/AFL). All patients were discharged 6 hours after the IV loading dose with a MCOT for 3 days. All patients had a 12 lead ECG within 12-18 hours of the baseline line MCOT transmission. Variation in heart rate and QTc was assessed. Results: A total of 24 patients were included in the study. The mean age was 65 + 7.3 years, 80% of patients were men. The mean difference between the QTc interval measured on 12 lead ECG and MCOT was 5.1 + 6 milliseconds [450 + 33 (EKG) - 445 + 39 (MCOT)], p=0.92. The mean heart rate difference between the two modalities was also not significant, p=0.726 [ 70.4 + 19 (EKG) -72 + 11.8 (MCOT), ΔHR=1.6 + 7.2 beats per minute]. Conclusions: MCOT can be considered as a reliable alternate to 12 lead ECG for monitoring of QTc in patients receiving AAD.