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).