An auditory pulse monitor for noninvasively detecting the amplitude of arterial pulses on a beat-by-beat basis. A light-weight optical sensor including a light source and photodetector is adapted for application to the skin surface of a subject over a tissue bed containing an arterial supply. The photodetector generates an output signal proportional to the amplitude of an arterial pulse, and an electronic circuit connected to the photodetector generates a signal having a frequency proportional to the photodetector output signal level. A speaker or other audio indicator connected to the electronic circuit generates an audible tone indicating the amplitude of the arterial pulse. Another aspect of the invention is an improvement in automated or automatic external defibrillators (AEDs). An AED is disclosed which optically detects arterial pulses after delivering a defibrillation shock and signals the need for CPR if it detects inadequate cardiac pumping following successful defibrillation.