ELECTROCARDIOGRAPHIC EVALUATION
Superficial 12-lead ECGs of all patients (Nihon Kohden Cardiofix V Model ECG-1550K Device 25 mm/s and standard 1 mv/10mm) were recorded before the treatment of COVID-19 infection and were evaluated by two independent cardiologists who were blinded to the characteristics of the patients. Heart rate, P-R interval, QT and QTc intervals, and QRS duration were recorded. The P-R interval was measured as the time from the beginning of the P wave to the beginning of the QRS complex in milliseconds. The QRS duration was measured from the beginning of the Q or R wave to the end of the R or S wave in milliseconds. The QT interval was measured from the beginning of the QRS complex to the end of the T wave in milliseconds. The QT corrected distance was measured using Bazett’s formula. The depression or elevation of the ST segment in the lead aVR from the isovolumetric line was measured numerically (STaVR). According to the T wave amplitude in the lead aVR, patients with a positive peak (>0mv) from the isovolumetric line were recorded as positive (positive TAVR), while patients with a negative peak (<0mv) from the isovolumetric line were recorded as negative (negative TAVR). The amplitude of the T wave (TPAVR) was recorded by calculating its negative or positive deflection from the isoelectric line. The TPAVR/STAVR ratio was obtained by dividing whichever value is greater by the other (large value/small value).