Heart vector magnitude. A simple recording system.
D001281:Atrial Fibrillation / Q000175:diagnosis; D006332:Cardiomegaly / Q000175:diagnosis; D002986:Clinical Trials as Topic; D003202:Computers, Analog; D006801:Humans; D006984:Hypertrophy; D014672:Vectorcardiography / Q000295:instrumentation*