Ventricular fibrillation involves the ventricles of the heart (lower chambers responsible for pumping blood) rapidly contracting in an disorganized pattern, and thereby limiting blood flow from the heart. This can be due to uncoordinated electrical activity. The electrocardiogram (ECG) generally shows irregular QRS complexes without P-waves. By contrast, the ECG for ventricular tachycardia will generally show a wide complex QRS with more than 100 beats occurring per minute. If sustained, ventricular tachycardia can also lead hemodynamic instability and compromise, resulting in pulselessness and poor perfusion to vital organs. thumb|Demonstration of electrode pad placement for defibrillation A defibrillator will deliver an electrical current through a pair of electrodes placed on the person's chest. This is thought to depolarize myocardial tissue thereby stopping the arrhythmia. Defibrillators can deliver energy as monophasic or biphasic waveforms, although biphasic defibrillators are the most common.
ventricular fibrillation involves the ventricles of the heart (lower chambers responsible for pumping blood) rapidly contracting in an disorganized pattern and thereby limiting blood flow from the heart this can be due to uncoordinated electrical activity the electrocardiogram (ecg) generally shows irregular qrs complexes without p-waves by contrast the ecg for ventricular tachycardia will generally show a wide complex qrs with more than 100 beats occurring per minute if sustained ventricular tachycardia can also lead hemodynamic instability and compromise resulting in pulselessness and poor perfusion to vital organs thumb|demonstration of electrode pad placement for defibrillation a defibrillator will deliver an electrical current through a pair of electrodes placed on the person's chest this is thought to depolarize myocardial tissue thereby stopping the arrhythmia defibrillators can deliver energy as monophasic or biphasic waveforms although biphasic defibrillators are the most common