Synchronized cardioversion is used on patients with
certain cardiac rhythms when it is necessary to avoid
applying the defibrillation pulse at an inappropriate
time – which could result in further deterioration of
the cardiac rhythm. Defibrillation pulse delivery is
timed from the ECG so that it is delivered within a
short time after the QRS portion of the waveform and
before a period of time (vulnerable period) of the
ECG when fibrillation may be induced.