A medical system for providing a defibrillation therapy to a patient includes a cardiac monitoring device (CMD) configured to sense and record physiological data indicative of the patient's cardiac function. The CMD includes a communication component. The system also includes an external therapy device configured to deliver defibrillation therapy, and configured to be positioned external to and supported by the patient. The external therapy device includes an external therapy device communication component. The CMD communication component and the external therapy device communication component are configured to operatively couple the CMD and the external therapy device to one another, so as to work as a system to detect and treat fibrillation.