A handheld defibrillation device is disclosed, operated by a single battery cell, and configured to deliver a defibrillation pulse to a subject via defibrillation pads. The defibrillator comprises an energy storage unit comprising a plurality of capacitive elements, a plurality of charger units, each charger unit being electrically connected to the battery cell for electrically charging a respective one of the capacitive elements, and a pulse delivery unit configured and arranged to discharge the electrical charges of the capacitive elements through the defibrillation pads. The charging units and the pulse delivery unit, and various other parts of the defibrillator are specially designed to permit compactly packaging the defibrillator inside a handheld pocketsize housing.