A biphasic waveform is energy delivered in two phases. During the first phase, the electrical current passes through the heart muscle, reverses direction, and then passes through the heart a second time. This efficient transmission of energy requires less current than that delivered by a monophasic waveform. Manual Mode operation is as easy as 1-2-3: 1 - Select an energy level from 2 to 200 Joules. 2 - Charge the unit. 3 - Deliver the shock. The HeartStart XL charges to its highest energy level in less than 3 seconds. ALS providers can also perform synchronized cardioversion and deliver non-invasive pacing

The HeartStart XL records a patient summary in either mode of operation. Patient data such as continuous ECG, shocks and alarm violations are stored in the unit's internal memory. Downloading and reporting data is available by using a data card. The Event Review Pro data management system allows authorized users to edit, store, and print reports. The HeartStart XL is designed to meet a wide variety of resuscitation and monitoring needs in one lightweight, easy-to-use device both in terms of in hospital and emergency requirements.