Apparatus and method for discriminating flow of blood in a cardiovascular system

摘要

An implantable cardiac stimulator delivers a first electrical shock via implantable stimulating electrodes at a time when there is substantially no flow of blood. At least one of the stimulating electrodes is disposed in a blood flow path of the cardiovascular system. The first shock is of insufficient energy level to cause defibrillation. An electrical potential is measured as a function of time between the blood-contacting electrode and a reference electrode following delivery of the first shock to obtain a first potential equilibration function under no-flow conditions. A second therapeutic electrical shock, of sufficient energy level to effect defibrillation, is delivered via the stimulating electrodes. A second potential equilibration function is measured following delivery of the second shock. The first and second potential equilibration functions are compared, and if the two functions are sufficiently different in morphology, it is determined that blood is flowing.