Instrumentation for Telemetering the Electrocardiogram from Scuba Divers

A system for telemetering the human electrocardiogram and other parameters over distances in excess of 600 feet through the sea is described. Versatility is obtained by using plug-in subassemblies in the transmitter for the parameters to be monitored. In view of the propagation characteristics of water, 55-kHz ultrasonic energy utilizing frequency modulation was chosen as the optimum transmission method. Problems encountered in underwater telemetry are outlined and techniques for their solutions are discussed. The results of tests are shown which indicate that electrocardiograms of good clinical quality can be obtained from free swimming divers.