Defibrillation aims to deliver sufficient transmural current to depolarise a critical mass of myocardium, allowing restoration of synchronised electrical activity. Inadequate energy fails to defibrillate, but excessive energy causes myocardial damage and risks of resumption of fibrillation. Defibrillation of supraventricular arrhythmias should be synchronised to avoid delivering a shock on the T wave of ECG, which may induce VF.
Defibrillation can be performed using either paddles or self-adhesive sternum below the clavicles and the apical pad in line with the nipple in the mid-axillary line firm force at least 8 kg should be applied to annual paddles during defibrillation. The monophasic waveform is supersized by a biphasic waveform which has a positive, followed by negative phase, delivered over approximately 10 ms. Biphasic waveforms are more effective than monophasic waveform for…
