Patent ID: 7162298

Claim:
A device for detecting the presence of cardiac activity in a patient, comprising: a detector circuit that is configured to detect the influence of a first defibrillation shock on the patient immediately subsequent to termination of a first defibrillation shock; an isolation circuit configured to electrically isolate the detector circuit from the first defibrillation shock, wherein the detected cardiac activity comprises fibrillation and wherein the detector circuit is further configured to detect if the fibrillation ceases immediately after termination of the first defibrillation shock and reinitiates within a predetermined time period after the first defibrillation shock; and a controller circuit wherein the controller circuit is configured to administer a second defibrillation shock having a second shock value that is at least one of substantially equivalent to the first shock value and less than the first shock value immediately if it is determined that the fibrillation has ceased immediately after termination of the first defibrillation shock and reinitiated within the predetermined time period.