The QA-40M and QA-45 Analyzers are precision instruments for testing defibrillators and, additionally with the QA-45, transcutaneous pacemakers. They are designed to be used by trained technicians. The defibrillator function of the QA-40M and QA-45 measures the energy output, and ensures that the defibrillator complies with specified requirements. QA-40M and QA-45 have built-in load resistances of 50 ohms, which roughly correspond to the impedance of the human body. The defibrillator pads are placed on the analyzers’ contact plates. Thus, the defibrillator is connected through the load resistance. When the defibrillator is discharged, the analyzers calculate and display the energy delivered. In the pacer function the QA-45 tests all types of transthoracic pacemakers. The testing is menu driven, and simple to operate. QA-45 measures and displays a pulse’s amplitude, rate, energy and width. It also conducts demand sensitivity tests, measuring and displaying refractory periods, and immunity tests, which determine the pacemaker’s susceptibility to 50/60 Hz interference. Testing with the QA-40M/45 is usually a matter of setting up the preferred simulation parameters. Using PRO-Soft QA-40M/45 simplifies the process by providing an all Windows-based environment through which simulation parameters are created by the user and sent to the QA-40M/45 unit.