Combined effects of graded hyperkalemia on activation and recovery.

We have demonstrated the progressive transmission delay in the A-V conduction system in graded hyperkalemia against a background of otherwise normal cations, and known blood gas relationships. This extends and further quantitates the work of others. We were unable to demonstrate sinoventricular conduction, as atrial activity was consistently recordable when surface P-waves disappeared. The His bundle appears to be the least susceptible conduction system structure to hyperkalemia. Finally, we have postulated the possible mechanism for the genesis of the sine wave, including loss of electrical gradient with resulting phase difference of QRS and T, associated with maintenance of His bundle activity with progressive, distal, Purkinje blockade.